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CAD Debate – Text vs Mtext

I have been using AutoCAD for almost 30 years. I wished and wanted something like MText for many of those years, now that we have had it for quite some time. I pretty much hate it, but I also like it for some things. Plain ole Text offers flexibility and consistency that MText can’t offer. MText offers some features that Text can’t offer. These are the reasons we still have both of them and not just one. Text and MText both have their places in our drawings. Problem is drafters tend to lean one way or the other and fail to balance their use. Older drafters tend to do everything in Text, Younger Drafters like the MText. Some Drafters, just go with whatever is in the drawing, and have no preference. In order to help your drawings improve in quality, consistency and improve your productivity it is important to know when and where to use Text or MText.

MText offers Paragraphs, formatting, an inline editor, word wrap, boundary limits and lots of other cool features. MText lends itself well to anything that would fit well in a word processor. General Notes drawings, Notes on Drawings, Multi-line occurrences of text, bulleted lists and such. MText offers an integrated spell, that is easier to notice and use than the one with the standard text command. Wordwrap is such a great feature for Notes. How many times can we add or delete from a note? Wordwrap allows the user to just type until done. The boundary of the MText entities keeps the lines from overrunning the area designated, and will add as many lines as needed. Bullets are a cool feature that can easily be done with MText. If you have MText on a drawing for Notes and such it works great at keeping the numbered bullet list indented and properly formatted. Keep in mind though you must use the indent feature. Often times people will just uses spaces to indent or hard returns with tabs. That kind of effort defeats the purpose. If you are going to use it, use it correctly. SPACES are NOT for creating indents or perceived justifications. See the Figure 1. Below. If using MText, make sure you and your drafting / design group KNOW how to use it. Believe it or not people still do the same thing in Word processors like MS Word.

Figure 1: MText reacts differently when used improperly. The above demonstrates what happens when the font is changed for the style of the text.
Figure 1a: MText Line Spacing can vary depending on the characters used in the line of text. Notice the last line of text, why don’t they line up with each other?

What’s not to love about MText? Plenty actually, sorry my bias is showing, grin. MText is not good for body text. I don’t believe it should be associated to Leaders, except when that leader is in fact associated with a paragraph of text and not an identifier. MText uses a boundary for placement and not a justification point. The boundary is hidden unless you have selected the MText entity or have text masking on and a color that is visible. MText is in fact more complicated than using standard Text. There are multiple parameters to work with, making copy and paste less appetizing because you copy parameters that are no longer applicable to the new destination. See Figures 2, 3, and 4 below. Ignore that some of the text below should in fact be Attributes in a block. Another topic I will discuss.

Figure 2: Normal view

Figure 2 shows what the drawing area looks like. Looks ok (regarding text)

Figure 3: Selected to show grips and adjustment controls of the MText bounding boxes.

Figure 3 shows the highlighted text with grips and bounding areas. (notice anything odd?)

Figure 4: Text Masking

Figure 4 shows what the area that each text boundary box actually is. Can you say copy and paste. Can you see the problems this could create?

The above text would have been much better as just Text entities. Justifications could be applied, line spacing, snap, and more could be cleaner and more consistent.

Figure 5: Problem with using incorrect MText with Leaders.

Figure 5 highlights the problem with using MTEXT with Leaders. This MText box happens to be Center Justified, another bad thing. When the cable size changes from #4/0 to 350MCM what happens? Had this been text. The line would have just expanded to the left (assuming Right justified to the Leader) and would have remained as a single line of text. MText is constrained and wordwraps the 350MCM to the line below and since it is center justified, creates the gap from the Leader. If this was a Find and Replace operation across the whole drawing, the drafter would not notice the second line and gap until they printed it out reviewed their check print. Text itself lends itself much better to body text, than MTEXT. More control over the placement and effects of change. Using lisp routines and such you can easily change the justification. Yes you can select an MTEXT Object and do the same pretty easily, but you have an easier effort using just text.

Figure 6: Some things just don’t line up.

If you look at Figure 6. You can see these don’t all line up too well. Why? Because these are placed by the bounding box of the MText entity and not the insertion point of the text. Will SNAP or OSNAPS help you here? NO they will not. The text inside the MText entity uses a dynamic text spacing method that positions the lines of text and is not controlled by snap or specific spacing controlled by the user. There are some settings to control spacing, but keep in mind the text on the line can be taller than the line before it.

In Figure 6 above, how would you get the Text on the Left to all line up? We are drafters, we make sure our drawings look professional and that text is not haphazardly placed all over the drawing. Alignment does matter. Each of these text entities has a different bounding box, and they are not as they should be. So what happens when you align them to the right. Take a look at Figure 7.

Figure 7: Adjusting MText alignment did not have the desired affect.

What happened. Crappy drafting happened. Crappy drafting happens when CAD users are not properly educated in what they are doing, or just don’t care. So fix it. If these were Text as I recommended. I would simply type in TJ (Text Justify Lisp command I wrote back in the late 80’s) pick the 3 pieces of text with a crossing, and then R for right justify, and pick a point. Done! It would not matter if the text was placed by center, left of right. It would all be corrected after I applied the TJ routine to it. To leave it as MText you would have to fix each bounding box, then move each box to the proper alignment, because none of them match. Yes you could actually write a routine to fix that too much like the one I used for text, but that would not fix the bounding box issues. Another step. Yes write another routine. Do you see a pattern here? Text has less to deal with in terms of placement. Control is at the Text entity and not the box containing the text.

I can go on and on about why Text is better in the use of Body Text. MText is hands down the best option for Paragraph use and on Notes. We have both for a reason, use them both for where they benefit the drawing the best. So take away from this post at the minimum.

  • Use MText where it works best as a paragraph or in notes and make sure you know how to actually use the indent features.
  • Do NOT use spaces to place text in either Text or MText.
  • Text is better for Body Text.
  • Use Proper Justification.
  • When using MText make sure your Bounding box is properly set.
  • Don’t just use MTEXT
  • IF you Copy MText Entities, adjust the Bounding box to meet the need of the new purpose.

Comments? Let’s hear them.

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CAD Basics 101 – Snap, OSnaps and Ortho

AutoCAD is as precise as you are when you are drawing. AutoCAD, last time I checked (which was long time ago) can actually handle up to 16 point decimal accuracy (It only displays 8). That’s pretty damn accurate if you ask me. Most of the time for the drawings I deal with 32nd of an inch is accurate enough. With tools like SNAP, OSnaps and Ortho, why would we find something that has a decimal value of something like 0.03570045687123. WHY? WHY? I ASK YOU, WHY? No reason. Excluding Metric conversions, and some occasional vendor data that have odd dimensional data. Let’s talk about these three very useful tools to help you draw more accurately and improve the quality of your drawings.

Snap allows you to set an incremental distance that the crosshairs move. Typically mine is set to 1/32nd of an inch. If I find myself needing to land in between that I use half of that 1/64th. Using Snap will prevent you from drawing on really oddball points. It always stuns the person when they tell me everything they draw is on 1/16th or 1/32nd and they don’t use snap. How does that work. Well it is actually simple. It’s called rounding. If your units are set to inches and architectural and your accuracy is set to 1/16th or 1/32nd, guess what will show up when you check the coordinate, or distance. Measurements are always shown based on your accuracy level in UNITS or Dimension styles. When you set your Units to Decimal with a decimal place of 8 decimals, then check that coordinate or distance, suddenly it makes sense. What read 1/8” before now read 0.125677301 or something like that. 1/8” is equal to 0.125” no more no less. Snap is simple enough to use F9 toggles it off and on.  Get in the habit of checking your drawing at setup. Establish a Snap length that works well for your drawing type. Check with your company standards or your drafting manager. Verify it.

TIP: Pair Snap with your Grid Settings and you will have a really good environment to producing better quality drawings.

Often times we work with existing drawings. Existing drawings brings work from others that might not be as disciplined as yourself. They may not know what snap or OSnap is. They may have just pulled up AutoCAD and started picking points, or the drawing may be the compilation of 20 years of copy, paste, modify from 10 to 20+ people working on it. The beauty of OSnaps is you can pick which one you want or use a preset setting of them to draw with. If you set Endpoint, MidPoint, and Intersection on, then AutoCAD will find the closet one that matches when you hover over an object or objects. Takes the guess work out. If you know you want the Endpoint, you can type it in at the command prompt, which is how I do all my OSnaps (yes, I type a lot), then AutoCAD will select the endpoint nearest to where you pick. F3 toggles OSnaps on and off. OSNAPS Command will pop up the Dialog box to let you set your default OSnaps.

TIP: An OSnap you might not know of is M2P (midpoint of 2 points). If you have a box or rectangle. How do you get the center point of that box. You can use M2P, then when it prompts for first point pick the ENDPoint of one corner and the second point will be the opposite (not one of the adjacent) corner of the box. The point returned is the center point of the box. You could also use POINT filters to do the same if you desired. Look that up. They come in very handy.

Ortho Mode basically means a straight line along the current axis. Most of the time this will be along the X plane or the Y plane, but keep in mind you can rotate your crosshairs using snap angle or even about a UCS. Keep in mind that if you use snapang, that your snap setting applies to the angle, so the snaps most likely won’t be where you thought they would be. That gives you some pretty good flexibility to draw a perfectly straight lines at any angle. For the most part though they will be along one of the AXIS, that can be X, Y or Z. The Toggle for Ortho is F8. Practice using this setting. You can pick a point and then try and line up the crosshairs so it looks straight and pick your next point, and it very well may look straight, but unless Ortho is on or Snap is on, it is highly probable the line is not actually straight. To verify, set your units to decimal and accuracy to 8 decimal places, then list the line. Check the points that should match, do they?

Snap, OSnaps, and Ortho are all great tools to help you draw better and more accurately. AutoCAD is not MS Paint after all. You can draw with precision and should. Remember if you are getting paid to use CAD. You are a professional, so be professional and produce quality consistent drawings. Like, share and / or comment. Let me know how I’m doing. Let me know if you have some topics you would like me to discuss.

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CAD Advanced AutoLISP Teaser

So far I have discussed a few things about improving our industry through sharing of knowledge. AutoLISP has been around since I started with AutoCAD in 89’. AutoLISP continues to be a strong API for AutoCAD. This Post will just be a little bit of a teaser to see how interested you actually are in AutoLISP. I will show you a few quick things you can do at the command line inside AutoCAD that will hopefully pique your interest enough to come back for more.

First a couple of things to note. AutoLISP uses Parenthesis to enclose code segments. Some special things to pay attention to are for every opening parenthesis there needs to be a closing one. Similarly for every opening double quote, signifying a string, there needs to be a closing one.

Try this out (in typical programming tradition)

(defun C:HELLOLISP() (princ “\nHello World!”))

The above AutoLISP code will create a command called HELLOLISP that is now available within the AutoCAD Dwg Session you loaded it in. So give it a try. Type HELLOLISP at the command prompt.

Congratulations you just typed in and executed your first AutoLISP defined command!

That’s great and all, but what good does that do me? Well, it basically shows you how easy AutiLISP is to use inside AutoCAD directly from the command prompt. Let’s do some more, but directly with AutoCAD commands.

Open a drawing, any drawing that has something in it, hopefully a good collection of entity types, circles, lines, blocks, polylines, wipeouts, text… Make sure it is a copy of the drawing and not one you care to keep.

Once inside your drawing lets erase all the text in your drawing. There are a few ways to do it, but this is after all an AutoLISP lesson. So let’s use AutoLISP.

Start the Erase command, then when you are at the Select objects prompt, type in the following. (pay attention there is a single quote char and is special to the AutoLISP interpreter.

Select objects: (ssget “X” ‘((0 . “TEXT“)))
18 found
Select objects: [Enter]

All text (excluding MTEXT, Attributes, and any text inside blocks) should now be deleted.

Try it with other entity types. (“LINE” ; “CIRCLE”; “INSERT” (Block inserts); “LWPOLYLINE”)

In this intro we will not dig into what each things means, but we will show you some easy stuff to try.

Let’s move on.

AutoLISP can be used as an In line calculator. Take for instance those Scale Factors we talked about in the Scale Factors Post. With AutoLISP you can enter them directly at the command line instead of using a calculator. Say you want to scale something down to 1/48th of its original size. Start the SCALE command and select your object to scale, pick your base point and then when prompted for the scale factor input the following:

(/ 1.0 48.0)

Make sure you use the decimals. We will discuss why in later lessons.

You can use this even without a command. Try it:

(+ 37 2.5)

(- 20 19)

(/ 1.0 2)

(* 12 12)

You can use AutoLISP to access system variables. Imagine you are inserting symbol into a drawing and you don’t actually know the scale factor. Is it 64 or is 96. Assuming it is a scaled drawing and we are in Modelspace. Start the insert command, pick one of your symbols to insert and then when prompted for a scale factor try the following input.

(getvar “DIMSCALE“)

This will retrieve the current dimstyle’s scale factor setting. If you only use dimensions in Paper space this will basically be one. Again this is just to show some quick things to try.

What if you are working and you have two versions of the same file opened from different file paths. You can look it up using AutoLISP at the command line.

(getvar “DWGPREFIX“)

The result is your drawing file’s path.

AutoLISP is AutoCAD’s version of LISP. LISP Stands for List Processing, so it means we can’t have a in intro to AutoLISP without processing a list or two.

Find a circle in your drawing and let’s work with it. Type the following at the command line, then pick the circle.

(setq myCircle (entget (car (entsel “\nSelect Circle: “))))

The result is a list of all the DXF data for that Circle. Now let’s look at the parts. Type the following at the command prompt:

(foreach dxfitem myCircle (princ “\n”) (princ dxfitem))

You should see something like this:

(-1 . <Entity name: 7ffffb05f70>)
(0 . CIRCLE)
(330 . <Entity name: 7ffffb039f0>) 
(5 . 1EF) 
(100 . AcDbEntity) 
(67 . 0)
 (410 . Model) 
(8 . MyLayer) 
(100 . AcDbCircle) 
(10 20.5482 9.05521 0.0) 
(40 . 0.854867) 
(210 0.0 0.0 1.0) 
(210 0.0 0.0 1.0)

What is all that? (You may need to hit F2 to see)  It is the data that makes up the circle. The AutoCAD drawing is a VECTOR format and not a RASTER format. In other words it’s data and not dots. Let’s wrap up with a quick discussion of what some of these things are.

(0 . CIRCLE)

0 is the DXF code for entity type. This entity happens to be a CIRCLE, Hopefully you picked a circle.

(67 . 0)

67 is the DXF code for space, ZERO means Model Space, ONE means Paperspace.

(8 . MyLayer)

8 is the DXF code for Layer. This entity is on the MyLayer Layer.

(10 20.5482 9.05521 0.0)

10 is the code for coordinate, a circle on has one coordinate at the center.

(40 . 0.854867)

40 is the code for Radius. This one has a radius of 0.854867

Now you see how easy it is to use AutoLISP. Now looking at the above, note that using AutoLISP you can change all those values. You could change it’s Radius, it’s Layer, it’s center point…. And so much more.

I hope you have enjoyed this AutoLISP Teaser. If you would like to see more, let me know in the comments section.

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CAD Basics 101 – Scales Part 4 (Paperspace)

This is the Last part of Scale factors. Today we will discuss Paperspace and how scale factors work with Paperspace. Paperspace is a feature that was added to AutoCAD R11, That’s R11 in 1990 and not 2011. R11 also introduced ADS (AutoCAD Development System) a C programming interface that extended the AutoCAD API significantly and eventually migrated to what is now ARX (AutoCAD Runtime Extensions) a C++ programming interface. Sorry, I started down another tangent there. Back on track. So Paperspace introduced a whole lot of different ways to present your data, but for the most part, people left it alone and continued utilizing only Modelspace.

Paperspace was slow to start and if I remember right a Regen occurred at every zoom. This was painful on slower 286 and 386 systems. Fast forward to today and Paperspace has evolved significantly over the years. It has been abused and exploited in ways probably not intended by AutoDesk. For the purpose of this post I will stick to talking about a single Paperspace tab. Paperspace allows you to use your titleblock in a space that actually represents the printed media you intend for your drawing to be printed on. This means 1/4″ text is actually 1/4″ in Paperspace. This also means that symbols placed in Paperspace are inserted at a scale of 1. Some symbols are appropriate for Paperspace and some are better left in Modelspace. So for the most part there is no scale factor applied to your objects in Paperspace, this does not include scaling to compensate for unit conversions handled by AutoCAD in the background.

So, where does the inverse scale factor, presented in Part 3, come in? The Inverse scale factor is used when setting up your viewports inside Paperspace. A Viewport is essentially a window that allows for zoom levels. You could also think of it as a camera lens if you like. Your viewport is typically a small polygonal area, typically a rectangle that can be used to show Modelspace content on your paperspace drawing area. This is accomplished by creating a viewport using the MVIEW command. Once created your viewport will typically zoom the extents of the Modelspace and show that in your viewport. Your viewport can be set to a desired scale. Click on the viewport and look at the properties of that viewport. Near the bottom of the properties you will see standard scale and below that custom scale. If you do not see your scale factor in the standard scale drop down you can simply type in the inverse value of your scale in the custom scale input box. The list of scales presented in the standard scale is based on what scales are loaded into your current drawing. Drawings often have the extra scales purged to reduce file size. If you don’t see your scale in the list and want it you can use the SCALELISTEDIT command to add or delete scales. Once the scale factor is set. AutoCAD will zoom to the level based on the center of the viewport.

With your viewport set to the correct scale factor, you should now see your drawing as it will look when plotted. So how do you control what’s in the viewport. What if you have matchlines that you need to match, what if you have a particular area you want to show inside your viewport. There are a number of ways to configure your viewport to show where and what you want. If your matchline area is already in Modelspace and your viewport is proportional in size and proper scale to the matchlines, then you simply double click inside the viewport to make it active and use the ZOOM command with the Window option and pick the lower left and upper right corners to define your view, use your OSNAPS. Then switch back to Paperspace and set the viewport properties to locked to avoid shifting your view. “what if my viewport doesn’t match my macthlines?” You either make the matchlines match the viewport or the viewport match the matchlines. How? Let’s assume you want the viewport to match the matchlines.

Let’s talk about how to get the matchlines and the viewport to match proportionally and by scale, then talk about an easy way to make them match. Measure your matchlines rectangle, let’s stick with some easy ones say X direction is 100’ and Y direction is 50’. Our scale for this drawing is 1/4″ = 1’-0” meaning we have a 48 scale factor and a 1/48th inverse sale factor. This tells us that to find out how big our viewport dimensions need to be X distance is (100’ times 1/48th ) and our Y distance is (50’ times 1/48th). In this case that is X=25” and Y = 12.5”. Remember that we have to convert feet to inches before multiplying. Otherwise your measurement will result in a feet and decimal foot measurement. 12.5” would be 1.042’ hardly something we want to use as our measurement because there is a rounding issue involved. Inches are much better to work with than decimal feet. Yes Mappers will disagree, grin. Now just use the grips of the viewport to match the size we need. You can draw a box around your viewport and match it, or use lines to offset it, or use coordinates to get it there, but you will need to get the viewport to match the measurements.

Yes there are easier ways. You don’t even have to know the measurements of your matchlines. One simple way is to use Ctl-Shift+C to copy your matchlines with a base point, preferably lower left corner, and hopefully it is a closed polyline. Switch over to Paperspace, Ctl+v to paste it at the lower left corner of your viewport. Use the Scale command to scale the “Last” object and select the lower left corner. Then either use scale by reference (48 : 1) or provide the inverse scale factor of 0.02083333. Personally I would use the Scale by reference as it will be more accurate. 0.02083333 is a run on decimal and we obviously can’t run it out forever. Yes there are a number of alternate methods. I suggest you get familiar with different ways and discover which one works best for you. The outcome is the same regardless, or should I say the desired outcome. Hints at another method is CHSPACE command, but your viewport should be large enough to contain the object you are changing space from. Keep in mind it will move the object selected to Paperspace, so if you want to keep the Modelspace object, use a copy of it to move to Paperspace.

Hopefully this has been educational for you or has the potential to be useful to someone you know. This concludes the scale factor 4 part post. Take a look back if you missed any of them. Please comment and share.

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CAD Basics 101 – Scale factor Part 3

Now that we know how to get a scale factor for our drawing, how do we know which scale to use? Luckily there are standard scales to be used. Engineering, Architectural, Metric are some of the more common ones in use and are actually physical tools for measuring distances on actual drawings. If you have been in design or drafting for any length of time you have seen one. These are standards that we need to maintain and use. Yes we could make up our own to better suit our drawing or fit closer to the title block size, BUT we will avoid doing that, as it will cause problems and issues later.

One of my favorite sayings is “Just because you can do something, does not mean you should.” This is also why I am writing these blogs, to help educate some of the best practices in our industry and hopefully help my readers better understand and share the purpose of them.

Let’s talk Architectural Scales: You have heard 1/4″ = 1’-0” in my previous posts. That is an Architectural scale. Pretty easily to identify as it has inches and to a foot ratio. Here they are:

Standard Scales Scale Factor Inverse Scale Factor (used in paper space)
3” = 1’-0” 4 1/4th or 0.25
1-1/2” = 1’-0” 8 1/8th or 0.125
1” = 1’-0” 12 1/12th or 0.0833333
3/4″ = 1’-0” 16 1/16th or 0.0625
1/2” = 1’-0” 24 1/24th or 0.0416667
3/8” = 1’-0” 32 1/32nd or 0.03125
1/4″ = 1’-0” 48 1/48th or 0.0208333
3/16” = 1’-0” 64 1/64th or 0.015625
1/8” = 1’-0” 96 1/96th or 0.1041667
3/32” = 1’-0” 128 1/128th or 0.0078125
1/16” = 1’-0” 192 1/192nd or0.00520833

 

We will get to Paperspace next post, but I wanted to list those values used in paper space here.

Engineering scales are recognized by 1” equaling a multiple of 10’. Standard Engineering scales are:

Standard Scales Scale Factor Inverse Scale Factor (used in paper space)
1” = 10’ 120 1/120th or 0.0083333
1” = 20’ 240 1/240th or 0.0041667
1” = 30’ 360 1/360th or 0.0027778
1” = 40’ 480 1/480th or 0.0020833
1” = 50’ 600 1/600th or 0.0016667
1” = 60’ 720 1/720th or 0.0013889
1” = 100’ 1200 1/1200th or 0.0008333
1” = 200’ 2400 1/2400th or 0.0004167

 

Metric Scales are pretty nice as the metric system is based on factors of 10. Metric Scales offer something the other scales don’t. You can mix and match the units as they fit your need. Typically they are used as in mm to meters, but can be adjusted to be any metric distance measurements to any metric distance unit. Common Metric Scales are (using millimeters to millimeters to avoid any confusion:

Standard Scales Scale Factor Inverse Scale Factor (used in paper space)
1mm = 20mm 20 1/20th or 0.05
1mm = 25mm 25 1/25th or 0.04
1mm = 50mm 50 1/50th or 0.02
1mm = 75mm 75 1/75th or 0.0133333
1mm = 100mm 100 1/100th or 0.01
1mm = 125mm 125 1/125th or 0.008
1mm = 200mm 200 1/200th or 0.005
1mm = 250mm 250 1/250th or 0.004
1mm = 300mm 300 1/300th or 0.0033333
1mm = 400mm 400 1/400th or 0.0025
1mm = 500mm 500 1/500th or 0.002

 

Keep in mind if you start mixing the metric units, you will need to increase or decrease the values in the table accordingly. For instance if you said 1mm = 1m that would not b1 1=1 that would be 1 = 100. So if you applied the same 1mm = 100m scale you would need to increase the value in meters to be 10000. Because there are 100mm in every meter. So keep that part in mind the above table is mm to mm.

Note: There are different units you can apply to your drawing as well in AutoCAD. The system Variable INSUNITS controls what unit setting your drawing is using. You can access it or change it easily via the UNITS command. This allows AutoCAD to automatically apply unit conversions when inserting or referencing different drawings into your drawing.

Now we see a number of different STANDARD Scales we can use in our drawings. Stick with these and it will improve the quality of and make your drawings easier to use and manage.

A few reasons:

  • Industry standards already in place
  • More likely to have tools, physical and automated systems are more likely to work with standards
  • Drawing quality and consistency

Next up is Paperspace and how all this comes together.

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CAD Basics 101 – Scale factor Part 2

So, we have a Model needs a border with a scale factor of 48. Where else do we use this scale factor? Symbols, Text heights, Dimensions, Leaders, Linetype scaling, line work settings, Grid and snap settings and don’t forget plotting your drawing, and more I’m sure. I won’t go over every possibility, but will cover some to make sure we understand the concept. In another post I will help those of you that are wanting to learn more about automating with AutoLISP or other AutoCAD API’s, develop your own setup commands to help set drawings up consistently and take some of the headache out.

A Symbol is typically something that is used in drafting to represent something that otherwise might not stand out in a drawing. Things like a North Arrow, Section Marks, Material Bubbles, Receptacles, Lights, Welding callouts, and so much more. If your standard North arrow is 1.5” long on your drawing, then you want it to appear that way on every drawing. I will write another post on which way is up later, lot of debate on something that should be simple. Back on track… The North Arrow will be scaled consistently in your drawing to match the scale factor of the title block you are using or the scale factor of the drawing as established earlier. Keep in mind we are still not discussing Paperspace. We are focusing on understanding model space for the time being. It is also a good practice to maintain a position relatively close to the same spot on the drawings. You figure out the distance and the multiply that by the various scale factors of your drawings and they all come out the same, regardless of scale. It is important to start with a 1=1 drawing and figure out where it goes.

Text can get a little more depth, but it is the same principal as we discussed in the previous post. Take the desired plot size for the media you are printing to. Multiply that by the scale factor and that is the height of your text. I highly recommend setting up styles for each text height. At one point we had Leroy styles to match as close as possible to the Leroy pen sets that were used in manual drafting. This concept was very beneficial, because, when pen plotters took forever to plot a drawing, the occasional word being misspelled could be picked up by a manual drafter instead of sending the drawing to the plotter again and waiting 30-60minutes, and wasting ink and paper. Today’s printers take seconds to print, so that is not much of an issue any more. Another method of just using text styles like T125 for 1/8” text T25 for 1/4″ text has been around for a while. The 125 and 25 being the decimal equivalents of the fractions.B125 would represent Bold text and could either be a different font, or just simply shown on a different layer that plots with a heavier pen setting to make it stand out.

Let’s move on to Linetype scaling. If you load a linetype into your drawing, you will notice it shows up pretty good in a base drawing, but what happens when you draw that line in a drawing that has a scale factor of 48. That line was designed to be displayed in a drawing of 1=1, so at a scale of 48 it is pretty much too small to see. In AutoCAD there is a system Variable called LTSCALE. I have seen LTSCALE set at 1.0, 0.5, 0.375, and even 0.25. What does that mean? Well LTSCALE is a factor applied to the dashes dots and parts that make up the linetype. LTSCALE applies to all lines in the drawing. Line definitions are stored in the drawing file once loaded, so keep that in mind when you are trying to track down why two drawings are different looking. They may actually have different linetypes loaded for the same name. Using 1.0 for our test case we discussed last post would mean out LTSCALE should be 48.0. If we had a standard setting of 0.5 LTSCALE, then our LTSCALE would be 0.5 * 48.0 = 24.0.

NOTE: CELTSCALE is not the same as LTSCALE and something that should be set and stay set at 1.0. Nothing worse than tracking lines with individual settings of an LTSCALE. Yes entities can have individual LTSCALE settings, not a good idea to use this feature as a normal process.

Grid and Snap are important drawing tools to help you draw more consistently and accurately. If you are drawing in a 1=1 drawing like a wiring diagram, P&ID, Or even a legend sheet, you will find your snap settings are pretty simple, something like 1/4″ grid and 1/16” snap. This allows you to have snap points between the grid points that are always 1/16” apart. This keeps you consistent, and often keeps your fellow CAD designer Drafters happy. We will cover proper use of these in another post. Will snap and grid setting work in a drawing that has a scale factor? Of course it will. But keep in mind sometimes, dimensional data may force you to draw off grid and off snap. Parts are manufactured all over the world and dimensional data isn’t always cooperative from vendors. Make use of these tools. To use them in your scale factor drawings simply multiply the scale factor by the typical/standard setting and you have your new value.

That is all for this post. Next post we will cover Industry Standard Scales and why you should not make up your own. Good luck and thank you for reading. Sign in and leave some comments, or ask questions.

 

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CAD Basics 101 – Scale factor Part 1

Scale factors – Wait… That’s basic?? Yes, yes they are. Scales or scale factors are used to provide a method for presenting a large area or small area on the desired media size that is readable by the end user. What does that mean? Well, a scale factor allows us to present our design to the people that will be fabricating or building it and present it on a piece of paper that they can actually hold. Scale factors can be found using good ole math. There are factors used in Scale Factors to size the things presented on your drawings accordingly. What does it mean to draw 1=1 (one to one)? Why draw one to one? I thought you said we draw so that it fits on a smaller sheet. Scale Factors tend to confuse more drafters that it should. They are actually quite simple to understand and apply, but if you don’t understand their purpose it can become confusing on knowing when and how to apply them.

Scales allow us to draw a building that is 60’ wide and 40’ deep and show it on a piece of paper that is 22” x 34” long (aka ANSI D-Size). CAD allows us some advantages over traditional drafting on the board. CAD allows us to draw full size (1=1) then scale our title block (border) around the full size (model) and then print it to fit (using proper scale) within the boundaries of a piece of paper. Board drafting required us to draw at scale. This meant that if you wanted to represent the 60’x40’ building on a 22”x34” ANSI D Size drawing, using 1/4” scale (1/4” = 1’-0”), you as a drafter would draw a line 15” long to represent a 60’ side of the building. That line is 15” regardless and it is on a piece of paper, or vellum, or Mylar or whatever media was being used. The point is, it was scaled, down, for the paper and not full size (1=1). With CAD we can draw in our real world model and create a building that is in fact 60’ x 40’, then scale our border up to allow the building to fit inside our border. This means our border is actually huge 136’ x 88’ in size. No at full size this will not fit on a 22”x34” sheet of paper. We can plot this drawing using a scale factor to make it fit on the 22”x34” piece of paper. Please note when applying scale factor for drawings we always use a scale that maintains aspect ratio. Not to confuse you, but that means whatever scale we apply to one plane of the drawing we apply to the other plane. On paper we have 2 planes, X and Y. Let’s do the math. 1/4″ = 1’-0”. First let’s fix the units so they match. There are 12” in a foot. So now our equation is now 1/4″ = 12”. For an equation to work we are apparently missing something.

Apparently it’s Algebra:

Next let’s verify our equation:

We now have a scale factor of 48. So what do we do with it? Our scale factor is used to calculate the size of something relative to the paper size to appear appropriately with the actual size of the drawing. Our title Block is 22”x34”, so if we multiply 22” x 48 = 1056” -> 1056” = 88’: 34” x 48 = 1632” -> 1632” = 136’ that is the size of our border in our full size model. Please note we are NOT discussing Paperspace….yet. Everything we are discussing is Model space at this time. This same principal applies to text and Symbols. If we want text to be 1/8”(0.125) tall in our drawing (model) then we would need to apply the scale factor to the text. 0.125” * 48.0 = 6.0” This means your 1/8” text would need to be 6” in height to print at on a 22×34 ANSI D Size sheet of paper. So what would the height of the text be if we plotted this same drawing to 11×17 (ANSI B Size)? Notice the sheet size is a 1/1 ratio scaled by half of an ANSI D size sheet of paper. That means the 1/8” text would now be 1/16” in height on the printed 11×17 print.

We will continue this in my next post…. Coming soon.

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Hello Everyone!

Welcome to SeeMSixty7, a place to discuss AutoCAD, Databases, Development and More. We don’t have to limit ourselves to just AutoCAD, though CAD in General.

Where to Start…. Why Start this Blog? Well I’m frustrated and disappointed in the direction of Drafting/Design. Over the years it seems quality has gone down, in my opinion. So let’s open that up for discussion. Keep in mind this is not a debate, just a place to talk about how to improve our industry.

AutoCAD has grown into a powerful CAD system that offers tons of features and abilities. Drafting in the last 10 years though has not improved as a result, from what I have seen. I believe there are a number of factors that are influencing this trend; younger drafters that have not been properly mentored or trained; offshoring to places like India; data driven systems that produce drawings; older designers that never really learned CAD efficiently. There are more, but I think those are the big ones.

Younger Drafters typically learn AutoCAD and have the belief this now makes them a drafter. Not quite. Drafting has evolved over the years in so many ways and has so many guidelines and semi-standards that should be followed. Keep in mind drafting in one industry compared to another may in fact contradict each other’s standards. The problem is made worse when a young drafter holds a position as a drafter for a year, and suddenly believes they are now a designer or worse senior designer. Reality is you are setting yourself up to fail if that is the case. Do your time and become a good drafter, before taking on being a designer. Your time drafting and better understanding of what you are presenting will help you be better at both. Learn from the older guys. they might not be the best at CAD, but they should be better at the design and the drafting. Something else to keep in mind, Engineers are not drafters, and unless they started as a drafter, they probably are not the best at instructing you on how you should draft or present your content on the drawing. That is not a knock against Engineers, but they are typically engineers because they are good at engineering, not drafting!

Offshoring to India is  sore subject when we see jobs leaving our cities to go to another country. Typically the people that trained many of those in India were designers/drafters who were reluctant to teach them how to draft, and frankly probably wanted them to fail. This is not a knock against the drafters in India or the people of India in any way. It is just a fact that people don’t like to train their replacement and then get laid off. I’m going to avoid the political points on all of this, but from what I have seen, the results coming out of India are the same as the previous paragraph, lack of experience in drafting and design. Quality is still not where it needs to be.

Data Driven systems that produce ISO’s, Loops, P&ID’s, One-Lines, Wiring Diagrams… I have been automating drawing processes for nearly 30 years. I created Loop generators from lotus 123/excel data back in 89. I Managed to generate over a thousand loops in a few hours. Keep in mind 286 processor with 2 MB of RAM back then. It wasn’t exactly fast. They were good looking Loops too, because I worked the templates to be clean, I knew the format of the data, I knew all the nuisances that would come up and wrote my code to compensate. Data Systems are typically taken out of the box, and data thrown into them and drawings start spitting out. These systems are written to fit a generic template or layout with a particular data format that works with the generic. When you tweak the data formats, the data model input into the system you tend to blow that consistency up, resulting in poor quality drawings. Automated systems are great. I love them, but they need so be flexible enough and the time needs to be taken to properly implement them.

Old Guys, of which now I’m either in that group or pretty close to it. LOL. I’m still in denial on that. Some of the “more experienced” designers started on the board, and begrudgingly moved into CAD in the late 80’s and early 90’s. I personally started on CAD and did some board drafting. I have a lot of respect for the board drafters, some serious skill and tedious efforts in that. Some took to CAD like a fish to water, others adapted as best they could. Keep in mind they didn’t grow up with  computer in the house. Technology was added much later in their years. Some it is natural, and some it isn’t. These are the people you can learn from. Appreciate their opinions, just because you know more about CAD than they do, does not mean you know more about drafting/design than they do. My father once told me. “You can always learn something from someone, and there is always someone that knows more than you do.” The “more experienced” can also learn some CAD from the “less experienced.”

This has been a lengthy intro, but hopefully we can start some good dialog and start sharing knowledge to make us all better. Thank you for participating. Create a login and start contributing. I will be sharing a wealth of information, tools and best practices with blog members.

 

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CAD Basics 101 – ByLayer, ByLayer, ByLayer

I can’t tell you how many times I have said this over my nearly 30 years of using AutoCAD. It still holds true. One of the beautiful things about CAD is control over the various aspects of the elements with ease. Proper drawing setup helps facilitate that and make your drawing more useable and reusable. If one thing CAD has brought to drafting, it is COPY and PASTE! Grin. I’m sure you have inherited a drawing or two from a previous project. One of the goals was draw once, use many, right? Layer, Linetype, and Lineweight should be set to bylayer. Resist the option to change any of these at the entity level. Why? Well, bylayer allows you to change any of those properties at the layer level and affect all entities on that layer with ease. Bylayer allows you to easily update a drawing to match other drawing standards. Bylayer helps others use your drawings and control their appearance without need to modify your drawing to better suit their requirements. This promotes better team environment and helps facilitate project communications.

First off you need to appreciate the purpose of a Layer. A Layer is an attribute or property of a drawing entity. Yes you can draw everything on Layer 0 and use different colors, linetypes, and lineweights all day long, but in the end you have something that is just not flexible or easily updated. Layers allow you to isolate components or elements that are logically grouped together. For instance, all Conduit goes on one layer called conduit and it is red. You could normalize even more if you like and create a conduit layer for each size of conduit. You could go even further and have a layer for Above and Below Grade Conduit and each size of conduit. Suddenly you have a large number of layers. Database rule: Normalize till it hurts, then de-normalize till it doesn’t. We will discuss databases and AutoCAD in another post. We also have other ways to identify conduit sizes, we can discuss that too in another post. With our Conduits split among two layers AboveGradeConduit and BelowGradeConduit we can control their color, linetype and lineweight from the properties of the layer command. Above grade conduit will typically have a linetype of continuous, and the belowgrade will typically be hidden or dashed. In an Electrical Drawing, Conduits should stand out more. The lineweight or color needs to allow for that. Both layers could share the same color and weight. The lineweight can be controlled by the color we plot to or by the lineweight property of the layer. Layers allow you to control visibility of those same elements. You can easily see all the conduits or specific elements of your drawing with simple toggles on layer visibility.

If you work for an Engineering company, you may have worked with multiple standards for different clients. You may have discovered that the colors don’t match, the linetypes don’t match or the layer names don’t match your company standards. With Layers and entities set at bylayer, bylayer, bylayer, it is easy enough to rename the layer, change the color, the linetype and or lineweight and you are done. Your drawing can now be used on another project that requires different standards. You can even automate that process easier if you are consistent in your normal approach. We can cover automation of tasks in another post. Manipulating properties at the layer level gives you a quick view to what changes on the screen. Imagine opening a drawing you were expected to copy from one project to another and there were minimal layers, and entities with color, and linetype controlled at the entity level. How much time does it take to look through the drawing and change what may or may not be conduit to a new color, and a different linetype? Don’t’ forget about the rest of the drawing entities.

Projects typically consist of team members, sometimes one, sometimes many drafters/designers working on a project and multiple disciplines. How often have you used another discipline’s background for your own? A piping designer will often reference in or use the background from the Structural department. When using another discipline’s background for your own, you should not need to modify their background in order to use it. As an Xref or even as a block, you can manipulate the properties of the Layers inside their background to control how it displays as yours. This process facilitates usability and ease of use. Imagine if the background you wish to use is not organized by layers and using bylayer settings. Imagine trying to control the display of those lines on your print. If the background uses red and your drawing uses red to show as a primary focus, how will your elements stand out. Simple, right, just open the background (your copy) and make the changes to all the entities that need changes at the entity level. Reference in or insert into your drawing as a block. Done, only took 10 minutes. 5 Minutes later, they updated the background because some equipment moved. Just do the same process. 10 minutes and you’re done. A few days later, and your lead wants to issue the drawing, you discover they changed the background yet again, lucky you checked. So again 10 minutes and you are done. Had this been done via layers, the updates would have been automatic / semi-automatic, and would not have required any time or minimal time to insure the update. This is one drawing we are discussing. I’m not sure about you but the last project I was on we had over 7000 drawings, and that was just the electrical group.

Take time explore layers and layer management, avoid drawing entities with individual color settings, linetype settings and or lineweight settings. This will make you a better CAD Drafter / Designer. If you benefit from this post, hit the like and or even share. Let others know you want to start bringing quality back into drafting.

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CAD Basics 101 – TEXT

 

I won’t bore you with rants about some of the, let’s say, subpar drafting efforts I have seen over the years. CAD has become more and more advanced and feature rich over the years, and I feel drafting quality has declined. Let’s try and help turn that around. Starting with Text. Text is used to communicate to the person reading the drawing. It is important that we communicate effectively and consistently. Text is basic so here are some basics checks for text.

  • Is text spelled correctly?
  • Is the text clear in meaning?
  • Is the text uncluttered and not overlapped by other line work in the drawing?
  • Is text positioned correctly?
  • Justified and aligned correctly?
  • Is text the right height for the subject matter (Body, Heading or Title)?
  • Text Width?
  • Layer?

Is your text spelled correctly? It is easy enough to verify your spelling. Yes we all make typos and get rushed, but get in the habit of verifying your spelling. Is the text clear? Does the text present the message you are delivering. Abbreviations are used quite frequently in drawings, but you should avoid them if possible, remember the goal is to deliver a clear message.

Is the text uncluttered and not overlapped by other line work in the drawing? Your text should not overlap or be overlapped by other elements in your drawing. Your text should be located in a spot that allows for text to be uncluttered. If your location does not allow for clean placement, you may need to break some of the background out or consider using a wipeout or text mask. I you choose wipeout or text mask methods, make sure you have good standards in place and have communicated the proper process for using them. Remember the printed result is what is used. If your system requires special settings for printing some of the issues that arise from wipeouts and text masks, then it is highly likely someone will print it incorrectly.

Is text positioned correctly? Your text should be relative in position to what you are identifying. A leader that stretches across 3” of printed material could easily lose its association. We will cover Leaders in another post. Is it justified and aligned properly. If you are like many CAD users, you simply copy other text in the drawing, change it and move on. This practice works great, but make sure the text you are copying is right to begin with. One of my personal favorites (read sarcasm) is when I copy a few lines of text, I then update that text, and then suddenly instead of it shifting as it should. The text actually changed position from where it should have been justified. For instance. It looked like it was centered, then when I changed the text to be longer or shorter, I discover it is Left justified. This is easily fixed, but, shows poor quality work on someone’s part. Make sure your alignment is correct. If you are placing an equipment tag inside an equipment outline and it fits centered and looks clean, great. If it is on the left or right of the equipment, Should it be left or right justified, these are things to look at. It may sometimes work, but it may also get confused with another piece of equipment. Check the presentation and make sure it is clear.

Is the text the right height, weight, width for the subject matter? Standards are what dictate these things. You should have some. If you are unaware of them, then ask. Text heights, weight, and width are often controlled by the text style. Text styles are a great way to maintain a consistent look in your drawings. Get to understand them. Note that text height and width are controlled at the text entity level and not the style level. The style simply sets the default for those. Text weight can be controlled in a few ways, Layer, color and by font selection. Again consult your standards on these. If the text is on the correct layer, you probably have the weight right. If the Font is set by the style correctly, you probably have the weight right. Color based plotting can control the weight as well, so keep in mind the best practice is to always draw bylayer for your color setting and not use the color setting at the entity level. Yes there are occasions when you should deviate. We will save bylayer topic for another post as well.

Some of you will relate to this topic, and think yes I wish more people understood this. If this is the case, forward this post on to them. Share the knowledge. I have found that typically most CAD users want learn and improve their skills. I’m sure all of us have opened a drawing and thought, “WHAT WERE THEY THINKING?” Some CAD Users are learning, CAD Systems like AutoCAD, have become so feature rich and full of functionality, often times new users are overwhelmed and not sure what the correct approach or setting should be. I am hoping to post more on CAD Basics on a regular basis. If you find these useful please share, comment or like. Thank you for reading.

Have an amazing day!