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Invalid geometry from extrude

codereclaimers
Enthusiast Enthusiast
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Message 1 of 6

Invalid geometry from extrude

codereclaimers
Enthusiast
Enthusiast

I stumbled across a case where an extrude creates what appears to be bogus geometry.  I've attached the design, please let me know if other info would be helpful.

 

This isn't some kind of blocking issue, for what that's worth--I just saw some unexpected behavior and thought I'd report it.

 

codereclaimers_0-1637635712665.png

 

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393 Views
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Message 2 of 6

g-andresen
Consultant
Consultant

Hi,

This is due to the taper angle being too large for the extrusion height.
The max. height for this angle is approx. 3.8mm.

 

@jeff_strater 
Maybe there should be an error message.

 

günther

 

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Message 3 of 6

codereclaimers
Enthusiast
Enthusiast

Thanks, I would have expected an error message, or at least for the health state of the extrude feature to be something other than HealthyFeatureHealthState.

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Message 4 of 6

TrippyLighting
Consultant
Consultant

@codereclaimers wrote:

Thanks, I would have expected an error message, or at least for the health state of the extrude feature to be something other than HealthyFeatureHealthState.


The extrude does create valid geometry! Valid in this case means it does not violate BRep rules of the geometric modeling kernel. That you consider it "bad' is a judgement call you should be able make and is better not left to some algorithm.

 

 


EESignature

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Message 5 of 6

jeff_strater
Community Manager
Community Manager
Accepted solution

actually, in this particular case, the geometry is, indeed bad.  There are some illegal faces created here.  The reason, though, is still the combination of too-short extrude + too-big taper angle.  The reason why you do not see an error in this case is that the operation itself succeeded.  We do not check the body after every feature for the simple reason that doing so would be expensive.  If we turned on body checking after every feature, performance would suffer a lot.  We are hoping to introduce a body check/repair command in the future, but until then, it's almost a "doctor it hurts if I do this"/"then don't do that" situation.


Jeff Strater
Engineering Director
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Message 6 of 6

codereclaimers
Enthusiast
Enthusiast

Thanks for the clarification @TrippyLighting and @jeff.strater!  

 

This particular example was created by an automated modeling script, and for now I can visually check results for bad geometry.  But if you do introduce some method to validate geometry via the API, I'd be glad to help test it. 

 

 

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