[cgma-dev] Faceting tolerances in OCC

[Tim Tautges]

Jane, could you check the implementation of this in OCC?

Steve, in general, users should beware of this tolerance setting for all engines, since it's commonly taken as "advice" 
to the engine.  I'm not sure it's appropriate for a warning message, even in OCC.  It should definitely be documented, 
though, if it's hardwired to be ignored.  That should probably go into the release notes.

- tim

On 12/08/2011 11:41 AM, Steve Jackson wrote:
> I am interested in two functions in CGM's OCCQueryEngine: get_graphics( Surface* ... ), and get_graphics( Curve* ... ).  Both these functions take faceting tolerances as arguments, and then silently ignore them.
>
> This becomes confusing for users who convert CAD geometries to Moab meshes (e.g. using dag-mcnp5, dagmc_preproc, or mbconvert).  When OCC is the CGM backend for a client of Moab's ReadCGM, all faceting tolerances are silently ignored.  This behavior should be documented, at minimum; it may also be helpful if ReadCGM issues a warning that faceting tolerances are being ignored for an OCC-based backend.  The ideal would be a fix to the OCCQueryEngine to support the faceting tolerance parameters.
> ~S

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              Tim Tautges            Argonne National Laboratory
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