Minutes from 102nd OpenVDB TSC meeting, August 17th, 2021, (EDT)

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

Additional Attendees: JT Nelson (Blender), Richard Jones (DNeg)

Regrets:

Agenda:

1) Confirm Quorum
2) Secretary
3) Google Forum
4) Autodesk collaboration
5) Siggraph talks / papers
6) Root Node Offset
7) VFX Reference Platform
8) Blind Data
9) NanoVDB
10) Next meeting


1) Confirm Quorum

Quorum is present.

2) Secretary

Secretary is Dan Bailey.

3) Google Forum

Request from Autodesk to resolve an issue with how symbols are exported on
Windows. After some back and forth, Nick proposed introducing a mechanism to
customize the VDB namespace as the easiest solution, ideally would also work
with the custom namespacing that SideFX is using. There may still be room to
improve symbol visibility.

4) Autodesk collaboration

Autodesk still interested in a collaboration. OpenVDB does not currently have
multi-resolution grids so would benefit the library. Ken to discuss further with
them to find out potential next steps.

5) Siggraph talks / papers

Jeff mentions two papers that are of interest:

* Displaced Signed Distance Fields for Additive Manufacturing

This paper efficiently stores a voxel displacement to the true surface on top of
a signed distance field for more accurate results without increasing resolution.
Primarily aimed at 3D printing, but could be useful to VDB.

* Swept Volumes via Spacetime Numerical Continuation

This paper attempts to solve the "stamping" problem when generating smooth
representations from moving objects. It works by storing timestamps with the
query samples and essentially performs a spatial search optimizing for the
temporal values to project back to the swept surface. Could be very useful for
fast moving collisions in VDB in particular among other applications.

6) Root Node Offset

Ken still looking at a 2048 voxel offset, he has run into some logistical
challenges attempting to reorganize the data in the grid but experimenting on
top of NanoVDB with a hope to bring a solution to OpenVDB to release in time for
VDB 9.0.

7) VFX Reference Platform

The VFX Reference Platform committee has confirmed a final deadline of 1st
November 2021 for release of OpenVDB 9.0 in order to include it in CY2022,
otherwise it will revert back to 8.x. The draft document has been updated to
tentatively show 9.x with a note to this effect.

8) Blind Data

After some discussion, decision made to revert back to using Index32 instead of
Index64 for blind data offsets, as changing this later will not need a change to
the Grid ABI.

9) NanoVDB

Andre has started looking at the build system for NanoVDB and asked a few
questions about integration. Nick provided some initial feedback on the PR, Ken
looking for a more detailed explanation in terms of CMake changes required.
Discussion to be continued.

10) Next meeting

Next meeting is August 31st, 2021. 12pm-1pm EST (GMT-5).
