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- From: David E DeMarle <
>
- To:
- Subject: [Manta] Re: Re: information about the acceleration structures?
- Date: Fri, 9 Apr 2010 19:35:29 -0400
Awesome, thanks.
David E DeMarle
Kitware, Inc.
R&D Engineer
28 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-371-3971 x109
On Fri, Apr 9, 2010 at 7:30 PM, Thiago Ize
<
>
wrote:
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BSP and CellSkipper you probably would never want to use since the BSP has a
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super slow build for relatively minor speed gains and CellSkipper is slow
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and just interesting from an academic view.
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RecursiveGrid is a very good choice when the rays are very incoherent and
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single ray traversal is just as good (or better) than packet traversal.
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This happens with path tracing for instance. The number of levels to use
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is described in my dissertation, but 3 is usually the right amount. The
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build is decent, but could be made much faster if someone spent the time to
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optimize it.
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KDTree is ok, but the version in manta is not as optimized as it could be,
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so I'd probably use DynBVH over it.
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DynBVH is usually a good acceleration structure to use. The build can be
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made faster by going into cmake and turning
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MANTA_USE_DYNBVH_APPROXIMATE to ON
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however that will result in slower traversal performance. Faster build
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algorithms exist and someone should implement it as well as parallelizing
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the build.
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The poor scaling with increasing triangles could be a result of the packet
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size being too big. Trying turning it down to see if it improves
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performance. The exception to this rule is RecursiveGrid which already does
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a single ray traversal so packet size is not an issue.
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If possible, I'd recommend flattening the groups so that there is just a
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single group and then building a tree over this since this will give the
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best performance. Otherwise, the type of structures to use would depend on
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how the objects are distributed within a group and how the groups are
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distributed.
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Thiago
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David E DeMarle wrote:
>
>
>
> Can anyone tell me about, or point me to descriptions of, the ?five?
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> different acceleration structures (BSP, CellSkipper, RecursiveGrid,
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> KDTree, RecursiveGrid) in Manta?
>
>
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> vtkManta uses DynBVH, and it appears to be the fastest so far, but it
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> doesn't seem to scale all that well when the number of triangles
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> increases. I am wondering if one of the others (with well chosen
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> settings) would be a better choice.
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>
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> So far, vtkManta isn't changing the contents of the DynBVH, so the
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> Dynamic nature of it isn't that important (but quick build times are
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> important).
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>
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> We do want to be able to have (groups of) triangles, cylinders and
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> spheres in the acceleration structure so a non-homogenous acceleration
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> structure is preferable.
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>
>
> thanks for any pointers,
>
>
>
> David E DeMarle
>
> Kitware, Inc.
>
> R&D Engineer
>
> 28 Corporate Drive
>
> Clifton Park, NY 12065-8662
>
> Phone: 518-371-3971 x109
>
>
>
- [Manta] information about the acceleration structures?, David E DeMarle, 04/09/2010
- [Manta] Re: information about the acceleration structures?, Carson Brownlee, 04/09/2010
- [Manta] Re: information about the acceleration structures?, Thiago Ize, 04/09/2010
- [Manta] Re: Re: information about the acceleration structures?, David E DeMarle, 04/09/2010
- Message not available
- [Manta] Re: Re: Re: information about the acceleration structures?, David E DeMarle, 04/11/2010
- [Manta] Re: Re: Re: Re: information about the acceleration structures?, Thiago Ize, 04/11/2010
- [Manta] Re: Re: Re: Re: Re: information about the acceleration structures?, David E DeMarle, 04/11/2010
- [Manta] Re: Re: Re: Re: Re: Re: information about the acceleration structures?, Thiago Ize, 04/11/2010
- [Manta] Re: Re: Re: Re: Re: Re: Re: information about the acceleration structures?, David E DeMarle, 04/12/2010
- [Manta] Re: information about the acceleration structures?, Thiago Ize, 04/13/2010
- [Manta] Re: Re: information about the acceleration structures?, David E DeMarle, 04/14/2010
- [Manta] Re: Re: Re: information about the acceleration structures?, Carson Brownlee, 04/14/2010
- [Manta] Re: Re: Re: Re: information about the acceleration structures?, David E DeMarle, 04/14/2010
- [Manta] Re: Re: Re: Re: information about the acceleration structures?, David E DeMarle, 04/14/2010
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