Better fix for T54457. It seems Debian compiles OpenVDB without ABI 3
compatibility, while Arch does enable it as is the default in the OpeVDB
CMake build system.
So now there's an option that the distribution can set depending on how
they compile their OpenVDB package.
This is used to determine which voxels are to be considered empty space.
Previously it was hardcoded for converting dense grids to OpenVDB grids
to reduce disk space usage.
This value is also useful for rendering engines to know, i.e. to
optimize ray marching.
Some other software cannot handle grid names with spaces in them. We still check for names with spaces so as to not break old
files.
This fixes T53802.
One crucial thing here: OpenVDB shoudl be compiled WITHOUT
OPENVDB_ENABLE_3_ABI_COMPATIBLE flag. This is how OpenVDB's Makefile is
configured and it's not really possible to detect this for a compiled library.
If we ever want to support that option, we need to add extra CMake argument and
use old version 3 API everywhere.
Issue was that before writing to disk grids are clipped against the
density field's tree to optimize for memory/disk space, which in the
case of simulations with no density field results in all grids having
empty trees.
For now avoid clipping against empty grids, but perhaps in the future it
can be interresting to have some UI parameters to let the user choose
the grid used for clipping.
simulations.
This commits implements OpenVDB as an extra cache format in the Point
Cache system for smoke simulations. Compilation with the library is
turned off by default for now, and shall be enabled when the library is
present.
A documentation of its doings is available here: http://
wiki.blender.org/index.php/User:Kevindietrich/OpenVDBSmokeExport.
A guide to compile OpenVDB can be found here (Linux): http://
wiki.blender.org/index.php?title=Dev:Doc/Building_Blender/Linux/
Dependencies_From_Source#OpenVDB
Reviewers: sergey, lukastoenne, brecht, campbellbarton
Reviewed By: brecht, campbellbarton
Subscribers: galenb, Blendify, robocyte, Lapineige, bliblubli,
jtheninja, lukasstockner97, dingto, brecht
Differential Revision: https://developer.blender.org/D1721
