Multi-level instancing

[leroyvn]

The current shapegroup code explicitly forbids multi-level instancing (i.e. instances within instances). Is this because of limited (human) resources, or is something technical preventing the implementation of such feature?

[njroussel]

Hi @leroyvn

I just looked this up, so I might be wrong. Both OptiX and Embree support more multiple levels of instancing. (For Embree, the maximum depth must actually be known at compile-time.)

In both cases, it seems to come with a performance cost. In addition, this would require quite a bit of additional work and interface changes to support in Mitsuba - I fear that this would introduce quite a bit of complexity.

[leroyvn]

That's pretty clear, thanks!