iRay and instances

[hglr123]

Heya

Octane Render now have ability to render instances.
Is there any news on iRay and instances?

BR!

[steve]

Is there any news on iRay and instances?

Just to be clear, iray in mental ray is, and always was able to render instances. What it typically does internally is, it flattens instances when transferring to the GPU. That has several benefits performance-wise, like building very compact acceleration structures (without indirections), and keeping the GPU execution kernel small, and less "instruction" expensive. The disadvantage is larger memory footprint in case of many instances.

In the end, the overall advantage depends on the scene and its usage of instancing. We have this topic on our list for future improvements, but feel this needs careful investigation to come up with a reasonable trade-off between rendering speed and memory savings.

Best, Steve.

[SunDevilDave]

Just to be clear, iray in mental ray is, and always was able to render instances.

Steve,

Could the same be said for Assemblies? Shouldn't they be even more efficient than even Instances??? Anyone that is interested in Instances would surely benefit from using Assemblies; especially in poly heavy scenes.

[steve]

Could the same be said for Assemblies? Shouldn't they be even more efficient than even Instances???

Theoretically yes, if you use multiple instances of the same assembly

An assembly is nothing else than a regular (sub)scene hierarchy, just prepared for on-demand loading during rendering. Creating several instances of it does not necessarily mean that only one copy is kept in memory, especially if the instances use different rendering flags that are propagated down the scene graph into the assembly. For iray, assemblies are always pre-loaded and resolved before transferring to the GPU.

Best, Steve.