Minutes from 57th OpenVDB TSC meeting, July 21st, 2020, (GMT)

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

Additional Attendees: Johannes Meng (Intel), Bruce Chernia (Intel),
JT Nelson (Blender), Peter Cheng (DW), Andre Pradhana (DW),
Robin Rowe (Cinepaint), Roman Zulak

Regrets: *Peter* C.

Agenda:

1) Confirm quorum
2) Secretary
3) Forum Issues
4) Windows/Blosc Issues
5) Fast Sweeping
6) #739
7) Merge/Dynamic Load Manager
8) 7.1 Deadline
9) AX Merge
10) Next meeting


1) Quorum was confirmed.

2) Secretary was Nick Avramoussis

3) Forum Issues

None to discuss

4) Windows/Blosc Issues

Ken, issues at NVIDIA with OpenVDB reading/writing examples files with blosc
compression (on Windows). Believe to be related to blosc setup but, as they're
confident 1.5 is being used, it could be something else. All agree that an
investigation into blosc versioning is a major issue. NVIDIA to open up an issue
with more information for us to diagnose.

5) Fast Sweeping

Dan, performance improvements have been completed and discussed with Ken.
Between 2-4x faster, however it does use more memory - this along with some
minor additional improvements remain but can be completed at a later date.
Remaining work mostly related to the return behaviour and type of the available
free functions. Discussion around the automatic termination behaviour of some of
the methods. Ken to investigate adding tolerance controls to detect increases
(or negligible decreases) from previous iterations and exit accordingly.

6) #739

PR to change the attribute transfer field on the VDB From Polygons SOP to a
string field with some common defaults as options. Dan, added point.v as a
default, perhaps point.Cd/.N should also be added? All agreed that the main
use of these drop down options are to educate users on how to specify
attributes and we can add more options later. Dan, confirmed that the PR will
not break existing scenes. Dan to merge as is.

7) Merge/Dynamic Load Manager

Dan, still investigating how best to provide this support. Tests with perfectly
overlapping SDFs perform significantly faster than the current NodeManager,
however completely non-overlapping SDFs are slower as they still need to iterate
over all levels of the tree. Could design user functors to return true or false
if subsequent iteration is required, however it would be nice if functors could
work with any NodeManager. Discussed free-function support in the context of a
merge header. Dan, could provide signatures which behave differently on const
presence. Concern that this behaviour is too obscure to users and may cause
unintended results when user implementation changes. Questions as to where this
functionality should live; in a dedicated Merge header or in the NodeManager
header.

8) 7.1 Deadline

Deadline for 7.1 changes set to 2 weeks from today (deadline 4th August).

9) AX Merge

Whilst all TSC members still want to work towards an AX merge for 7.2, may have
to consider the possibility of delaying either the 7.2 release or AX depending
on TSC review time. Nick to also contribute the AX Houdini SOP as part of the
initial AX merge.

10) Next meeting

July 28th, 2020. 1pm-2pm EDT (GMT-4).
