Instances support ?

[Polar01]

Hi,

Do you expect to add instances support ? And maybe to also support other kind of primitives (Hair, curved surfaces, etc...)

thanks

Krys

[SvenW_Intel]

Embree 2.0 supports instancing, see tutorial02. We consider support for hair important, as triangulating hair yields in too many triangles to handle efficient. Thus, hair support will likely come in a future release.

[Polar01]

Nice, thanks...

[Polar01]

BTW,

I'm currently looking at Embree and would like which strategy you use for building your SBVH with instancing support ?

 I see 2 main methods to build such structure :
1) Create 2 BVH, a top-level tree that contains and handle all the instance (pointing to other trees) and several sub BVH, one per object/instance. It seems to me that it will degrade to performance because on the top-level tree I cannot do spatial split !!

It will degrade the performance mainly when I have a lot of objects and a few instances only.

2) Create one SBVH, where each instance is a leaf that contains a simple bounding box, for such leave I will not do any spatial-splitting.
The main problem is that the Instance-Leaf will contains an object_id and I should be able to traverse the tree only for this object_id.
But is it possible to do with a SBVH where we have a list of triangle (with duplicates etc...), they are not ordered by object, so it seems I
have to traverse the whole scene... and it will be expensive ?

Or maybe you have another strategy ? Is there some information about that somewhere ?

Thanks

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[SvenW_Intel]

Embree support the SBVH only over triangular geometry. Thus you can enable the SBVH for your objects you are instancing, but not for the top-level BVH over the object instances.