3D Solids are Shrinking Over Time

[CMCORE]

Hi, I've been having an issue with random 3D solids shrinking by a few thousandths of an inch over the course of a drawing's life. For example, I have 6" wide steel channel extruded at 120" long, with no problems. Then randomly, I notice the channel changes from 6" to 5.9950" in height days or weeks later. This has happened many times since I've started using Autocad 4 years ago, and I've used each year of Autocad version since so I don't imagine it to be an update issue. The height is consistent across the length of the solid. Also, I have not done any presspull or sub-object selection filter modifications to alter the height of the extrusion. Along the same lines, I might have 2 of these extrusions 80" apart and then mirror objects from one channel to the other channel. For a length of time, the objects will maintain being 80" apart, but at some point one of the channel extrusion shifts by .0023" or .0076", etc., so now mirrored objects are 79.9977" apart or something like that when I work with the drawing again. Maximum annoyance.

Any ideas what could cause this?

I uploaded a photo of the extrusion, and a photo of the 2D shape that I extruded from. Right now I don't have an example of the mirroring issue.

Thanks for any help in advance! Patience is appreciated; this is my first post.

[Gabriel_Watson]

Are those solids too far away from the 0,0,0 origin of axes?

Try a reset to defaults to see if that corrects the issue:
https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/How-to-reset-AutoC...

[CMCORE]

Thanks for the reply.
How far is too far? Everything I make is within 360" from the origin. In regards to settings, I could try that. It may take a while before I can confirm if that fixed it or not. As a side note, I am running off of two different computers; one at work, one at home, both of which are set up somewhat differently. I've experienced the issue on both. Of course, one computer might be causing the issue and therefore saving the drawing with the error, and then I see the error on the other computer.
Any other ideas that I could try after resetting defaults would be welcome also!

[Valentin_CAD]

@CMCORE ,

Post the drawing to troubleshoot.

Also, check your UCS = World   and   View = Top.

[CMCORE]

Thanks for the reply. Changing my UCS and view doesn't seem to change the solids. I've uploaded a file that I've stripped any proprietary information from, and also attached a couple of photos of where to look at. Inside the DWG file there are a few copies of the 2D shape that I always use to make these particular extrusions.

[pendean]

@CMCORE the only members in your file that appear to have been drawn/created incorrectly (as in the are not exactly 6.000 high) are these two elements: much like your 5.000 member, it just looks like a drafting/creation error, not much else.

[CMCORE]

Correct, not all of the channels are wrong. The rear, front-bottom, and side-top ones are incorrect, but all of them were based on the same 2D face. Notice in this next pictures, the front face channel profiling was made by subtracting from the side channel, however neither channel lines up in the front anymore, and they are definitely flush at the bottoms of the two channels. I don't see how I can make two channels from the same profile, subtract one from the other, and have one of those channels be 6" tall and the other 5.9950" tall. I repeat this type of process so often without issue, and am always moving things based upon whole measurements and object snaps. If it is an error on my part, I'm not quite certain what I could possibly do differently. I could see accidentally dragging one of the 3D vertices of a corner, but this is a whole region of a solid...

Basically, it happens periodically, and I'm curious if anyone else has experienced it before, or if AutoCAD just isn't the software to be doing 3D as much as I am.

[dany_rochefort · Accepted solution]

@CMCORE Channels shrinking over time can happen if your forget to water them occasionally. 😂🤣

All jokes aside tho, there is no way this can happen. Can you imagine how many companies would be in trouble if this were truly the case?  As mentionned, it boils down to a manipulation error. 

You can definetily build huge with autocad 3d these days. Best tip i can give you is to use a better Steel Shapes addon. Your channel shape geometry was not correct. I HIGHLY recommend Al Rogers Steel Mill *lisp which is free to use. 

You can get it here : https://blog.draftsperson.net/al-rogers-steel-mill/

[pendean · Accepted solution]

@CMCORE thanks for the feedback. Sadly, auto-shrinking object resizing (with no user input, deliberate or accidental aka "periodically") is not a feature or bug of AutoCAD through 2024. Sorry.

[CMCORE]

Thanks for the input. That addon looks like something I need real bad! I was not aware that that was around; I'll get that installed and that should eliminate errors like these.
Much appreciated.

[CMCORE]

I'll see what I can do to adjust accordingly then. Thanks for helping me out!