This commit makes uses of the new OpenVDB IO in Mantaflow (introduced in 781f783a66ac).
From now on, fluid cache files in OpenVDB format will contain a list of grids per frame (before: one .vdb file per grid per frame). Besides regular grids, particle systems are also stored using OpenVDBs PointGrid data structures.
All older cache formats will remain fully functional:
- Uni caches (.uni) files are still available from the UI and can be used as before
- Raw caches (.raw) are no longer available from the UI, but loading them is still possible
- Old OpenVDB caches (one .vdb per grid) can no longer be baked either, but loading them is still possible.
It is also no longer possible to choose file formats for 'Noise' and 'Particles'. Instead there are now options to set the file format for 'Volumetric' and for 'Mesh' data.
Known issues (planned to be resolved soon):
- OpenVDB files are currently not taking into consideration the clipping value (FluidDomainSettings). Empty cells are therefore being written too. Depending on the scene, this can make file sizes unnecessarily large.
- Domains are not being exported at their world position. Instead they are always clipped to the origin.
Issue was that the noise simulation was trying to bake with a minimized domain size (adaptive domain initializes domain with size (1,1,1)). Similarly to the base resolution bake, there should be no noise baking happening at those domain sizes - a domain at this size is considered empty.
This is more in line with standard grids and means we don't have to make
many special exceptions in the upcoming change for arbitrary number of volume
grids support in Eevee.
The workbench shader was also changed to fix bugs where squared density was
used, and the smoke color would affect the density so that black smoke would
be invisible. This can change the look of smoke in workbench significantly.
When using the color grid when smoke has a constant color, the color grid
will no longer be premultiplied by the density. If the color is constant
we want to be able not to store a grid at all. This breaks one test for
Cycles and Eevee, but the setup in that test using a color without density
does not make sense. It suffers from artifacts since the unpremultiplied
color grid by itself will not have smooth boundaries.
Differential Revision: https://developer.blender.org/D6951
This commit adds bounding box support for emission objects - similarly to flow objects. Before, each effector object had to iterate over the entire domain. Bake times of scenes with multiple obstacles improved significantly with this optimization.
Other improvements that were implemented alongside the bbox feature:
- Option for subframe sampling for effector objects
- Option to enable / disable effectors (can be animated)
- Optimization for static objects. If a flow or effector object does not move and the adaptive domain is not in use, the bake time will be optimized further by reusing the flow / effector grids from the previous frame (no recalculation).
Cache files are currently loaded via the Manta Python API. With very big caches this can slow down the viewport playback. Especially smoke simulations, which just load grids and no meshes, can suffer from this. This fix solves this problem by directly loading the cache files from disk (no Python). This fix has been in the works for some time. The developer of this patch is ready to handle any potential fall-out of this patch quickly.
Cache file loading for mesh and particle files now works through the direct update_structures functions. The final cache mode now also only bakes the most essential files and is therefore not resumable anymore.
Files from /intern/mantaflow handle the communication between core Blender code and Mantaflow itself. It's the bridge to communicate with Mantas Python functions.
Code from /intern/mantaflow/intern/strings/ is pure Manta code and would likely need less attention in the review.
Reviewed By: sergey
Maniphest Tasks: T59995
Differential Revision: https://developer.blender.org/D3851
