Is there a possibility to implement custom type of geometric primitives? Okay, I understand, that mantra or other renderers may ignore them, but they may serve as helper geometry for DOP-context, for example, or procedural primitives may use them too (I'm not sure, just hoping).
One of such type I see is hierarchial volume grid, octree or similar based (have plans), may be - subdivision surfaces (no plans to implement , just for example)
I seem, it not so difficult - similar for custom SIM_Geometry implementation, with difference in GL-rendering implementation.

Thank you!

Sorry annoying with this theme.

I have progress in it - derived a class from GEO_Primitive (used GEO_PrimVolume as reference), wrote a simplest SOP, producing such primitive, and GR-extension, to render it to viewport.
Okay, everything compiled fine, even SOP works, GR-extension draws geometry. Nice! Right now this primitive does nothing, just exists, contains one vertex and transform, and draw as box caps, for simplicity.

But I implemented a lot of method wit very approximate knowledge about their meanings, so when I'm trying to work with that primitive (to apply transform, for example) - Houdini crashes.
I can't understand, why it happens, may you look at code to explain mistakes/misunderstandings?

Thank you!

Code file