Misplaced/distorded triangulated sub-shapes

Andrej Kudinov's picture
Andrej Kudinov
Thu, 02/18/2021 - 13:07
Forums: 
Data Exchange and Application Framework

Hello,

I've run into a publicly available STEP model that has some sub-shapes (see 'pipe_acc') that are distorted or misplaced after import and triangulation using OCCT 7.5.0. The same issue can be observed in CADAssistant 7.6.0.dev.

The attached images show the result in CAD Assistant and also in VariCAD where the result looks correct.

I wasn't able to identify whether this is a triangulation or B-Rep issue. Of course, it is possible that the file is not well-defined and VariCad makes some kind of shape repair.

I would like to kindly ask you to verify whether this is a model issue or there's a bug in STEP import/triangulation.

Let me know if you need more information.

Thanks in advance,

Andrej

 

 

Attachments: 
Image icon correct_subshapes.png
Image icon distorted_misplaced_subshapes.png
Kirill Gavrilov's picture
Kirill Gavrilov
Fri, 02/19/2021 - 15:59

I wasn't able to identify whether this is a triangulation or B-Rep issue.

If this would be triangulator issue you would see inconsistency between Shaded and Wireframe presentations, but they show the same problem.
So it is a B-Rep definition problem (either, incorrectly healed geometry, which was already broken in STEP file itself, or a bug in a STEP translator).