Where's the 'validate' command? How to debug BREP geometry?

[dunderhead]

Hi Autodesk, 

There're references to a 'validate' command that's supposed to (??) help diagnosing geometric problems in BREPs. But I can't find it!!!

The background is that I'm working with very complicated shapes. And here the CAD engine intrisically keeps colliding with the nature of organic forms: curvy surfaces combine easily result into minute features that make bad geometry. That's at least the case when the result is presented for finite-element analysis. For example, Autocad's Algor meshing algorithm is easily tripped up (and others too, it's really the result of bad input).

Below is an example that's from a T-spline with a star-point on an edge that's sewn to a brep patch. The isocurves apparently form a too sharp angle! Here the CAD engine doesn't complain, but it's not a "good" geometry and it won't mesh. Many more examples arise once you start cutting and combining solids that originate from T-splines -- I've encountered up to a dozen different strange error messages from the CAD engine!

Is the 'validate' command able to help me with that? I've resorted to IGES export, meshing in external CAD tools, and inspection of STL mesh to debug CAD engine problems.  They'll show up as microscopic self-intersecting surfaces or extremely sharp triangles. (I know I can mesh directly from Fusion, but that entailed some other problems.) And, I've learned that 'stitch' is much preferred to 'combine' because of numerical instability that unavoidably arises when recombining surfaces that have been subject to cuts. I've also learned that the 'interference' command is of little use, because when geometry is bad, then it'll just report no interference (in error) or suggest a repair technique that's not actually implemented with timeline on.

thanks,

-dh

[innovatenate]

Where is this validate command referenced? Is it in the API documentation?

You maybe able to use the Inspect tools, curvature map analysis, draft map analysis, or a zebra analysis to uncover these issues.

Thanks,

[dunderhead]

Nathan: thx for reply, you ask:

>  Where is this validate command referenced? Is it in the API documentation?

Yes, very much so, indeed enter "validate" in the search bar in the Fusion app, then you get to:

    http://fusion360.autodesk.com/resources/akn/view/NINVFUS/ENU/?query=validate  (excerpt below)

which is an analysis that seem to cover the kinds of issues (wrong geometry, overlaps, ...) that I encounter in a currently protracted process (involving Autodesk Simulation or other tools). Just what you'd need before even attempting FEA!  

However, I've looked and looked and this command really isn't there under patch!!!  Except I just found out: if you go to DM mode it'll materialize, but I don't want to throw away my history. Anyways, as a workaround, I pasted my brep body into a new file and ran the analysis there. So the Summary tells me that I have one overlapping surface. Not good, but now the Summary doesn't show me where as far as I can tell! Hmmm, so is there more I can do?

-dh

Validate dialog box

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Validate verifies the quality of an imported model. It checks the selected bodies, attempts to repair bad surfaces, and then stitches together any surfaces that can create quilts or solids.

Patch Inspect Validate

• Validate Surfaces Select the surfaces to check.
• Tolerance Sets the tolerance between surfaces.
• Checking Level
  • Basic Covers a set of topological, geometric, and uncertainty errors.
  • Standard Covers the Basic errors plus intersecting and overlapping faces.

Parent topic: Inspect panel