Memory consumption relation on GAS?

[m001]

Thank you for your answer.
I always use compaction and all the build flags discussed in the links to the given threads are always the same. As you presented in your OptiX Apps I also use numSbtRecords == 1 but yet with the difference to have the (MDL)-material-related stuff within the SBT record, which does not allow a face-based material index. So I will move that out of there and obviously need to do some benchmarking as you said.

But obviously to me it seems you also think, that

@droettger

many smaller GAS require more memory than one big one,

as I assumed.

But additionally I hoped for a guess on the AABB structure when splitting geometry.
You said fewer overlaps lead to higher speed and so I thought there is also a memory downside with that.

What I found from the links so far is:

@droettger

The accelerations structure itself is always a bounding volume hierarchy (BVH) and that uses axis aligned bounding boxes (AABB) over each individual primitive and a hierarchy over them.

@droettger

The AS builder for triangle primitives is the most sophisticated of the three since that is the most often used case. More work is done to generate a potentially better BVH.

When I understand that correctly the number of AABB structures for primitives remains the same in both cases (one GAS or multiple GASes).
But the hierarchy over them is build separately (in case of multiple GASes) and would be shared on one big GAS; So that seems to cause some overhead when splitting into several subsets.