SUBTRACT doesn't work

[RChalmers2]

I'm using AutoCAD 2015.

In the attached file I cannot get the yellow solid to SUBTRACT from the magenta solid.  It does a UNION on them.  If I try to make an INTERFERENCE solid I also get weird results.  INTERSECT also doesn't work.

I cannot try to  RECOVER the file because AutoCAD always (and I means always) freezes when I run recover.

Can anybody help with this?

Thnank you,

[nestly2]

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RChalmers2 wrote:

 ....In the attached file....

Attachment apparently didn't work

[nestly2]

There appears to be something wrong with the yellow solid.  The two solids do not intersect, but as you said, INTERFERE creates an interference object that appears to be the same volume as the yellow object, except with some anomolies near the other object.

XPLODEing the yellow object then recombining with SURFSCULPT appears to fix the issue.

AUDIT finds two errors, both apparently related to 4 blocks named AME_VW. which appear to me to be empty blocks. Perhaps selecting them with QSELECT deleting,then purging will remedy the RECOVER problem?

BTW, any two or more Solids can be UNIONed.... there's no requirement that they touch.

[RChalmers2]

Thank you nestly2.  

So you don't see that the objects intersect; or do you mean that INTERSECT doesn't work?

XPLODEing and recombining with SURFSCULPT did not work.

The work around I came up with is to make the arch on the yellow object go out a little bit past the magenta object on either side.  Then it worked.

Deleting the empy blocks followed by purging did fix the RECOVER problem!  Thanks; that's very helpful.

[nestly2]

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RChalmers2 wrote:

 So you don't see that the objects intersect; or do you mean that INTERSECT doesn't work?

XPLODEing and recombining with SURFSCULPT did not work.

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 I originally tested the file with AutoCAD2015.  After Xploding and recombining with SURFSCULPT,  Interfere command reported that the objects do not intersect. I mistakenly assumed that INTERFERE was correct, but now that I've done it again and switched views, I can see the solids do intersect and that INTERFERE in 2015 is giving an erroneous result. 

With 2014, Xplode + SURFSCULPT + Interfere  returns the same erroneous result as the original objects.

Sorry for the mis-information.  At this point, I have no idea what might be causing the problem, I only know that your geometry trips up both 2014, and 2015, but in different ways. 

Glad you found a work around.

[JDMather]

I would be reluctant to trust this geometry very far (invest a lot of time).

I opened it in Autodesk Inventor, unstitched, ran quality check, re-stitched back to solids and ran quality check again.

Still got the same incorrect behavior.

I think I would toss this one and start over from scratch.