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[Manta] Re: Re: Re: Re: Re: Re: information about the acceleration structures?


Chronological Thread 
  • From: Thiago Ize < >
  • To: "' '" < >
  • Subject: [Manta] Re: Re: Re: Re: Re: Re: information about the acceleration structures?
  • Date: Sun, 11 Apr 2010 21:20:59 -0600
So RecursiveGrid is crashing with more than 100k triangles?  That's odd. I've gotten it to build 10M+ triangle scenes.  Are these triangles distributed in some weird fashion?  For instance, are the triangles large and overlapping each other so that a single triangle ends up being in lots of grid cells?  Any chance you could send me a screenshot of what the 100k scene looks like?

Here's an example where I built a 1M tri scene on my laptop:

$bin/manta -scene "lib/libscene_triangleSceneViewer.dylib(-rgrid -model /Users/thiago/data/models/happy_vrip.ply -triangleType Wald_tri)" -nodisplaybench 10 10
Recursive Grid built in 9.577648 seconds for a 1087474 object scene
There are 1, 457, 51970, 0 grids per level for a total of 14674215 cells
7 x 18 x 7
Benchmark completed in 1.37217 seconds (10 frames, 7.28771 frames per second)

So 1.4s to render 20 frames and it took 9.5s to load the model and build the structure with the recursive grid.  The peak memory usage during the build was about 250MB and for rendering it stayed at 250MB.

$bin/manta -scene "lib/libscene_triangleSceneViewer.dylib(-DynBVH -model /Users/thiago/data/models/happy_vrip.ply -triangleType Wald_tri)" -nodisplaybench 10 10
DynBVH::preprocess START (1087474 objects)

DynBVH build time: Total (24.1661)
object_ids initialization (0.366518)
build (23.6126)
updateBounds (0.18699)
num_nodes = 1188560

Benchmark completed in 0.984006 seconds (10 frames, 10.1625 frames per second)

So DynBVH took 2.5 times longer to build than recursive grid and was 1.36x faster to render. It's peak memory usage was 300MB during the build (more than the rgrid) and then 240MB during rendering.  So from a build perspective rgrid wins hands down, at least for triangle meshes.  Incidentally, as an example of why rgrid's build is unoptimized and could be much faster, I tried building the same scene using my optimized grid build (not in manta) and I get a build time of about 1s (on one thread).

Thiago

David E DeMarle wrote:
" type="cite"> 
I'm not familiar with GridSpheres, but I would assume that RecursiveGrid
would be a much better grid structure than that.  RecursiveGrid has the nice
    


Sorry I meant RecursiveGrid, not GridSpheres in my email.

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