Merge pull request #1113 from Idclip/tsc_notes

Add TSC meeting notes from 2021-06-22.

Author: Idclip

tsc/meetings/2021-06-22.md

@@ -0,0 +1,131 @@
+Minutes from 96th OpenVDB TSC meeting, June 22nd, 2021, (EDT)
+
+Attendees: *Nick* A., *Jeff* L., *Dan* B., *Andre* P.
+
+Additional Attendees: JT Nelson (Blender), Richard Jones (DNeg),
+Johannes Meng (Intel), Bruce Chernia (Intel)
+
+Regrets: *Ken* M.
+
+Agenda:
+
+1) Confirm Quorum
+2) Secretary
+3) PyBind11
+4) OpenPRs
+5) VDB Visualize SOP
+6) Bug report on VDB Clip SOP not supporting cameras with overscan.
+7) Continuing discussion on VDB Visualize Tree SOP
+8) JT looked at the transcript for the OpenVDB SIGGRAPH course, which looks
+9) Next meeting
+
+
+1) Confirm Quorum
+
+Quorum is present.
+
+2) Secretary
+
+Secretary is Nick Avramoussis.
+
+3) PyBind11
+
+Nick has sent an email outlining the proposed work. All agree with Dan that the
+work can be incrementally completed. A feature/pybind11 branch exists for the
+target of this work. Nick to post as a Github Issue. The feature branch is to
+be kept in sync on subsequent releases of OpenVDB.
+
+4) Open PRs
+
+Deprecating StringGrids: All approve but should wait for Kens approval too.
+
+TBB 2021: Nick, incomplete CI. Majority agree that this should not hold up this
+work. Jeff, already downstreamed some of it into Houdini. Nick to merge. We
+can release a new (minor) version of VDB with this support. This needs approval
+from Ken and we should discussing the versioning required.
+
+EXR 3 (no PR, related to a proposed TBB release): How we bump VDB with the TBB
+2021 changes is sort of related to how we would release a new version with
+EXR 3 support. All agree that the path of least resistance is to make EXR
+support in the command line tool optional, then add support for EXR 3. There's
+still a question about the VFX platform's 2022 versioning if we don't support
+it before EOY.
+
+hsvtorgb: AX PR adding color conversion methods. Rich, tested against VEX's
+implementation which seems to clamp inputs going from hsv to rgb. Jeff, hue is
+most likely wrapped and saturation is clamped. Nick to make these changes.
+
+Counting Tools: Dan, ran into some issues with g++ AX builds exceeding memory
+limits. Fixed by forcing the CI to build on one thread. PR needs approval.
+
+CMake variable for Houdini DSOs: Dan, needs approval. There were issues with
+proposed alternatives (building individual targets with makefiles) so Nick
+agrees this proposal is fine. One outstanding point was the fact that there
+are two CMake variables which are attempting to achieve the same thing. The
+first is documented at the top of the Houdini CMakeLists.txt file and turns
+off nodes. Dan's new system turns nodes on. Ideally we would have a single
+variable which supported both. Nick, a regex string would be good.
+Introducing this new system is not ideal as it stands but can be improved
+in the future.
+
+Grain size dynamic node manager: Still no clear path forward here.
+
+5) VDB Visualize SOP
+
+Dan has parallelized some of the geometry construction from the VDB visualize
+SOP. Points from voxels is now much faster. Sold + wireframe generation is not
+parallelized. As part of this, Dan has removed lots of old compile time logic
+specific to SESI/DWA. Dan, also trying to add slicing support, a common feature
+done as a post processes to visualize a slice of a VDB. Jeff, this can be a
+pain due to relative bounds moving or absolute index coordinates changing over
+a frame range. Nick, solves this by clipping the input geometry though this
+isn't the exact same solution as it needs a bounds to define the slice. Dan to
+experiment with some solutions.
+
+6) Bug report on VDB Clip SOP not supporting cameras with overscan.
+
+Dan gets a bug report in VDB Clip SOP when a user sets the window size to 1.5
+from the camera that you feed in, the SOP doesn't take into account the
+overscan when you do that. It is implemented differently with different SOPs,
+e.g. the SOP Occlusion Mask. Dan thinks that it is good to clean up the logic
+across the different SOPs.
+
+However, the current SOP is not in the OpenVDB repository and is still owned
+by SideFX. Dan asks if this can be open-sourced. Jeff says that he should get
+the code into the open source repository.
+
+7) Continuing discussion on VDB Visualize Tree SOP
+
+Andre asks Dan: when he tries to slice the VDB, then will it always be axis
+aligned? Dan says yes. His plan is to do the slice by plane: x-axis, y-axis,
+and z-axis and have a relative 0 to 1 offset to where it lies in the bounding
+box, similar to what the volume slice does. Instead of sampling the volume, he
+wants to 'snap' the voxel values to the plane, so that as you move from one
+voxel to the next, it will jump to the next slice. By doing that, you can also
+show all of the leaf nodes and internal node wire-frame. The main idea being
+visualizing everything that intersects the plane. Jeff thinks this is a good
+idea because the Visualize Tree SOP is about exact voxel-values representation.
+Jeff suggests making a visualization based on solid boxes with color instead of
+points and to be careful with GL_LIT attribute and to set it to equal 0. Jeff
+is excited that this makes debugging a VDB easier.
+
+JT thinks that this may be a good project for an ASWF program where they have
+people do Google summer-of-code projects. Dan thinks that the parallelization
+can be tricky with parallelizing across topology.
+
+Andre asks for reference on how to do parallelization for geometry creation
+using HDK. Jeff suggests appendPointBlock. You can do the same thing with
+primitives. Dan says that the best example is the SOP_CopyPacked example in
+the HDK sample.
+
+8) JT looked at the transcript for the OpenVDB SIGGRAPH course, which looks
+mangled. He asks if it is useful to have somebody to do a better transcription
+on his end.
+
+Jeff says that SIGGRAPH should be responsible. Dan says that they have SIGGRAPH
+volunteers.
+
+9) Next meeting
+
+Next meeting is June 29th, 2021. 12pm-1pm EST (GMT-5).
+