Idiomatic way to traverse Rhino's scene graph?

Rhino Developer
1

Hi all,

Say I create a Rhino model with a box, bezier surface, and sphere, each with its own transformation matrix. Now I’d like to export this model information as parametric objects (i.e. a file encoding “model has: a cube of dimension <1,1,1> with transformation T1; a bezier surface with control points <0.5,0.5>, <0.5,0.5> and transformation T2; a sphere or radius <1> with transformation T3”). Ideally I’d just be able to export my model as a X3D file (as it supports these object types natively), but Rhino is triangulating all geometry on export. If I can’t retain this parametric information through standard export formats, can I traverse the model database to generate such a file myself? Any pointers on what parts of the API might be relevant? Is this information even recoverable from within the API?

Thanks in advance!

2

It is possible to traverse Rhino’s object table with both the Rhino C++ SDK and the RhinoCommon (.NET) SDK.

Rhino objects do not maintain a transformation matrix. Rather, their geometry reflects their precise position in 3-D space. Not sure how this effects your plans…

1 Like
3

Thanks Dale! Much appreciated. Looks like Rhino.DocTables.Tables.ObjectTable should get me started. As long as the exact position and orientation of the object is in the ObjectTable, I should be able to reconstruct the matrix w.r.t. WCS origin. Thanks again!

1 Like