Minutes from 111th OpenVDB TSC meeting, November 2nd, 2021, (EDT)

Attendees: *Ken* M., *Jeff* L., *Andre* P, *Nick* A., *Dan* B.,
*Rich* J.

Additional Attendees: JT Nelson (Blender), Bruce Cherniak (Intel),
Greg Hurst (United Therapeutics), Kyle Wardlow (United Therapeutics),
Sean McDuffee (Intel)

Regrets:

Agenda:

1) Confirm Quorum
2) Secretary
3) Forum

1) Confirm Quorum

Quorum is present.

2) Secretary

Secretary is Jeff Lait.

3) Forum

a) Question about custom types.

Someone suggested hijacking matrices.  But this is a sign that n-tuples would be a good idea.

But what about instantiation?  This is why instantiating tools explicitly is good, and instantiating the tree itself is less useful.

There is the choice of having run-time tuple size vs template types.

Suport for templated tuple size needs some specific functions pulled off the grid.  Eval min/max would fail, but why is it on the grid in the first place?

There are lots of obstacles in the way.  This would require persistence to go through with.

Half grids also have this issue.

4) Next Version

We have a planning document 
https://docs.google.com/document/d/1F1hmGnS1kIMobnfgpTJ6SYSrEPhC2B0WQAlt-idAo5w

We will go over this and discuss next week, to strike out what is done and elevate what is important.  Homework for this week is to review this document.

5) Volumetric Assets

Sean McDuffee is on the TAC for the Asset Repo Group.  They have a new license to allow film quality assets to go out for research and vendors.

https://wiki.aswf.io/display/ARW/Assets+Repository+Home

Intel has some high quality cloud assets.

10 variations of each type of cloud, 3 resolutions of each. Wispy clouds and big puffy clouds.  Density/size are comparable to Disney cloud, but more variety.  8gb for largest clouds, 87gb for full set.  Stored as float currently.

The Asset Repo group meets bi-weekly on this.

What about high res fluid sim with the corresponding surface?

What about all the clipping/thresholding that you do to reduce density before hand off?  Such as clipping velocity to density.

Possibly we should get a presentation on a set of tools that does this.

Can we find SDF assets for the asset group?

TSCs, such as ours, will be pinged from the asset group to see if various assets are proper warts-and-all exemplars of production assets.

6) V9 PostMortem

Hectic release. But complete!

Ken found building nanovdb locally still fails unit tests as no data directory, but the CI is passing.

The CMake system was left to the last minute which made it hard to get working.  Not well with one person maintaining build system.  VDB has too many build configurations.  We should have done the main merge earlier.  The optional dependency on VDB is odd with NanoVDB.  The optional data directory has been an issue.

Explicit instantion killing the CI was a surprise at the last moment.  If we had brought it in earlier, we'd have noticed it.  We should lock down two weeks before the release rather than having panic at the end.

Was it a perfect storm?  Nano with lots of optional dependency.  And a firm deadline.  What could we do differently?

Merging earlier would have helped.   CI covers so many configurations bringing any new project in will have lots of issues.  The windows bug was a genuine bug, for example.

We could have merged explicit instantiation earlier.  But the NanoVDB was waiting for some re-orgs that made it impossible to work on CI earlier, even if it had been merged.

Can we automate the configurations?  Build was 2 hours, weekly was 2 hours, any new PR would trigger another 2 hours.  We should have a one week grace period from the release and when we stop doing anything.  So during that week only PRs are things that are needed for the release are accepted.

Can we run the CI on the feature branch?

We'll do another pass on the CI to get the time down.  The explicit instantiation has hurt the AX times.  Current free account is very painful to use as we need to keep threads down to avoid memory overrun.

Dan will look at ccache to improve things, but the fear is it might evict the Houdini downloads.

What about setup time for Windows builds?  Can we get Windows images?  Currently 17 minutes setup on Windows.

We are now experiencing the end-user build times.  So we should try and push to see if we can get better hardware for our CI.

We should release 7 days before whatever the actual VFX deadline is.

7) Next meeting

It will be shifted 1 hour for DST changes.

Next meeting is November 9th, 2021. 1pm-2pm EST (GMT-5).
