SubD confusing ONX_Model::Read

[colomon]

A customer has sent me a 3dm file which my openNURBS v7-based software cannot read; ONX_Model::Read returns false. Allegedly this file has a SubD object, and if they delete the SubD object and try to import that version of the file, it works fine. (For comparison, if I try to read the v7_rhino_logo_subd.3dm example file, ONX_Model::Read returns true, though my software doesn’t actually do anything useful with the SubD objects yet.)

Um, I’m hoping I get a chance to attach said file at some point in this topic creation process, and then hoping that you guys can take a peak and tell me if the file is correct or not. Or that this problem will ring bells with someone out there.

Thanks,
Sol

[colomon]

RhinoSubD.3dm (67.6 KB)

[wim (Wim Dekeyser)]

Hi Sol -
Does this help?

Rhino3dmIO, openNURBS Support for SubD to Brep, Nurbs, or Mesh?

We’re not going to give away our mesher for SubD that gets you a tight limit surface mesh, but we do give away what might be considered good enough. There are two OpenNURBS functions that you can use to get a mesh. bool ON_SubD::GlobalSubdivide(unsigned int count); ON_Mesh* ON_SubD::GetControlNetMesh(ON_Mesh* mesh, ON_SubDGetControlNetMeshPriority priority) const; You can subdivide an ON_SubD instance to a desired level and get the control net mesh for visualization. This is available in Ope…

-wim

[colomon]

Sounds like that will be a big help for me with SubD in general=, thank you!

But this specific file does not get far enough into the import that you could call those functions; it fails utterly much earlier.

[dale (Dale Fugier)]

Hi @colomon,

The file is readable by the example_read project included with the openNURBS toolkit. This project uses ONX_Model to read .3dm files.

Here is the output of that example:

RhinoSubD.txt (32.1 KB)

– Dale