Prevent BVH building

Cycles Development
#1

Hi,
is it possible to use cycles without building a BVH or any other type of acceleration structure? I’m trying to prove some theoretical analysis on ray traversal performance.

Found a line (116) in cycles/bvh/bvh_params.h

/* fixed parameters */
enum { MAX_DEPTH = 64, MAX_SPATIAL_DEPTH = 48, NUM_SPATIAL_BINS = 32 };

Is max_depth related to bvh tree branch limit? I could then set to 0 or 1 and have quasi linear loop over all objects?

Also a there is a requested_layout when building the bvh and one called ‘none’. Maybe I can force this?

Thank you for any insight!

PS. was looking at cycles X source code found here: bvh_params.h · rB

#2

You could try setting the MAX_DEPTH to some low value, and you may need to increase max_triangle_leaf_size also.

To choose the BVH layout, go in the preferences enable Developer Extras and then under Experimental enable Cycles Debug. That will give you a Debug panel where you can pick the BVH2 layout rather than Embree.

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