Merge pull request #1318 from apradhana/TSC_2022-02-22

Add TSC meeting notes from 2022-02-08 and 2022-02-22.

Author: apradhana

tsc/meetings/2022-02-08.md

@@ -0,0 +1,76 @@
+Minutes from 120-th OpenVDB TSC meeting, February 8th, 2022, (EDT)
+
+Attendees: *Ken* M., *Jeff* L., *Andre* P, *Nick* A., *Rich* J.
+
+Additional Attendees: Sebastian Gaida, Greg Hurst (United Therapeutics), Karl
+Marett (UCLA), Bruce Cherniak (Intel), Kyle Wardlow
+
+Regrets: *Dan* B.
+
+Agenda:
+
+1) Confirm quorum
+2) Secretary
+3) Forum
+4) Undefined Behavior Sanitizer in Coord Hash
+5) ASWF Open Source Forum March 10
+6) VDB Blend
+7) Next Meeting
+
+--------------------
+
+1) Confirm quorum
+
+Quorum is present.
+
+2) Secretary
+
+Secretary is Andre Pradhana.
+
+3) Forum
+
+a) Issue 1301
+
+Question about making ZLIB to be optional when using BLOSC. Nick thinks that
+the solution brought up in the issue is correct, i.e. we need to get rid of
+the if statement in the CMakeLists that says that if you use BLOSC then you
+also need to use ZLIB.
+
+b) PR-1282
+
+Ken has reviewed PR-1282 and made a few suggestions. Jeff will approve the PR.
+Ken will wait for the submitter to make the required changes. If, after awhile,
+there is no reply from the submitter, Ken will merge the PR and will submit
+another PR with his fix.
+
+Jeff signed off this PR. Greg Hurst will test Ken's proposed fix.
+
+4) Undefined Behavior Sanitizer in Coord Hash
+
+Nick says that we have an undefined behavior sanitizer in VDB. There was a post
+specifically static analyzer warning of undefined behavior. Nick has been trying
+to fix these, primarily signed overflow. He is now asking about this issue in
+Coord's hash. There is a method in the Coord class that returns hash, but it may
+overflow. Jeff says that we should reinterpret_cast.
+
+Ken proposes to fix the sanitizer and Nick will review it.
+
+5) ASWF Open Source Forum March 10
+
+This means Ken has to present something related to VDB
+
+6) VDB Blend
+
+Andre talks about VDB Blend, which is an implementation of SIGGRAPH talk by
+Sony-Imageworks: Levelsets in Production: Spider-Man 3. The disadvantage of this
+method is the need to have a pretty wide narrow-band level sets for it to work well.
+Jeff and Ken likes the idea of doing dilation on the intersection region between
+the two level sets. One may use extrapolate technique to define a meaningful
+signed-distance value in this dilation region. Once this is done, we can apply
+the blending method in this dilated region. Ken also mentions that he has published
+a paper on this in 2002 called Level Set Surface Editing Operators. Jeff thinks that
+we should have a separate SOP for VDB Blend.
+
+7) Next Meeting
+
+Next meeting is in one week, February 18th, 2022. 1pm-2pm EST (GMT-5).

tsc/meetings/2022-02-22.md

@@ -0,0 +1,85 @@
+Minutes from 122-nd OpenVDB TSC meeting, February 22nd, 2022, (EDT)
+
+Attendees: *Ken* M., *Jeff* L., *Nick* A, *Dan* B., *Rich* J., *Andre* P.
+
+Additional Attendees: Sebastian Gaida, Xavier Martin Ramirez (ILM),
+Greg Hurst (United Therapeutics), Kyle Wardlow (United Therapeutics),
+Bruce Cherniak (Intel)
+.
+Regrets: None
+
+Agenda:
+
+1) Confirm quorum
+2) Secretary
+3) Forum
+4) Rasterizing VDB from Particles
+5) Next Meeting
+
+--------------------
+
+1) Confirm quorum
+
+Quorum is present.
+
+2) Secretary
+
+Secretary is Andre Pradhana.
+
+3) Forum
+
+a) Google Forum v.s. Github Discussion
+
+Ken will post on the Google Forum to encourage people to embrace Github
+Discussion. Dan will post on the Github Discussion to say that you should also
+see the Google Forum.
+
+b) Blosc
+
+There are two issues related to Blosc. Nick will take a look at it.
+
+c) VDB Print and VDB memusage
+
+Someone uses VDB Print and sees a discrepancy between the expected VDB memory
+value with the one printed. This shows that delayed loading is working. Ken thinks
+that we should just provide "(out-of-core)" printing. All you need to know is the
+number of leaf nodes and the type of data to know what is the in-core memory usage.
+Providing these numbers without loading the VDB is useful.
+
+d) NanoVDB (Github Discussion 1307)
+
+This question is from Sebastian Gaida.
+
+4) Rasterizing VDB from Particles
+
+Dan and Xavier Martin Ramirez did a presentation on rasterizing VDB from
+particles. Several points:
+ - This is different from Nick's work on particle rasterizer. This seems to
+   have more applications in rendering, e.g. in the context of volumetric
+   motion blur. Nick's work is in the context of particle-skinning and creating
+   a level set from points.
+ - This tool is to rasterize attributes to VDBs, e.g. in the context of
+   rasterizing camera motion blur particles. It can rasterize density, mask,
+   integer, float, and vector. It does clipping based on frustum.
+ - Unique to this tool is rasterization to frustum grid.
+ - Xavier shows that their approach to associate a voxel with a pixel on
+   the screen will keep rendering the VDB to more efficient than rendering
+   points. Memory usage is lower because we have fewer voxels than particle
+   numbers. The output from volume and particle renderings look identical.
+   The timing to finish a volume render using this approach is also faster
+   compared to particle based rendering.
+ - Nick is interested in a graph that demonstrates performance over time
+   in relation to underlying resolution.
+ - Dan talks about the different modes it supports: accumulators, max, and
+   average.
+ - It supports the use of mask.
+ - This is based on scatter method. Nick's implementation is based on gather
+   because he targets level sets applications, SIMD optimization, and
+   prioritizing thread synchronization.
+ - It targets different use cases as Nick's point rasterization, so both
+   methods should coexist in OpenVDB.
+ - Nick will talk about his point rasterization PR the next time.
+
+5) Next Meeting
+
+Next meeting is in one week, March 1st, 2022. 1pm-2pm EST (GMT-5).