Basic support for velocity updates with the APIC method.
This commit adds APIC to the already existing dropdown menu for the simulation method. The APIC plugin within Mantaflow has been updated to the latest version.
Being able to adjust the distance between fluid and obstacles comes in handy when trying to achieve a fluid motion over inclined obstacles.
Depending on the slope of such obstacles, already small adjustments of this value can help when particles stick to obstacle surfaces (i.e. make particles not stick to obstacles).
A general refactor / fix commit that should clear out the issues that have been reported on external forces and moving effectors (e.g. T79537, T81660, T80088).
When creating a particle system to display simulated particles, the phystype needs to be set to 'no physics' so that particle positions are just copied and not integrated.
This will make the "Reset to Default Value" operator in button right
click menus work for the fluid modifier. Before they always reset
the values to 0.
Differential Revision: https://developer.blender.org/D9206
Do not escape flow / effector objects if they have a disabled use flow / use effector flag.
Vertex velocities still need to be kept track of in order to have correct object velocities when enabling flows / effectors intermittenly. It is possible though to skip the emission loop if the flags are disabled.
This refactor is in response to an unreported bug in which overlapping, moving colliders produced an unstable simulation.
Things that change apart from cleanup through this refactor:
- Effector objects with no velocities (either non-animated or animated but non-moving object) will explicitly set zero velocities in their flow bounding box.
- When applying object velocities to the global grid, they will now be accumulated per cell (add and not set velocities). Later they will be averaged with the object count at any cell.
All the changes made in the branch `soc-2020-fluid-tools` are included in this patch.
**Major changes:**
=== Viewport Display ===
- //Raw voxel display// or //closest (nearest-neighbor)// interpolation for displaying the underlying voxel data of the simulation grids more clearly.
- An option to display //gridlines// when the slicing method is //single//.
==== Grid Display ====
- Visualization for flags, pressure and level-set representation grids with a fixed color coding based on Manta GUI.
==== Vector Display ====
- //**M**arker **A**nd **C**ell// grid visualization options for vector grids like velocity or external forces.
- Made vector display options available for external forces.
==== Coloring options for //gridlines// ====
- Range highlighting and cell filtering options for displaying the simulation grid data more precisely.
- Color gridlines with flags.
- Also, made slicing and interpolation options available for Volume Object.
Reviewed By: JacquesLucke, sebbas
Differential Revision: https://developer.blender.org/D8705
Load all grids when the grid display option is turned on. Otherwise, the grid from the viewport display options might not have been loaded from the cache.
The problem in this case was that the flag for active fire was not set. With hidden flow sources the flag was not updated in update_flowsflags().
The solution for this is to take the active field from the config cache file.
Before: If the current frame is out of the cache start/end range, the viewport will show the fluid as it was on the last frame that was still in the cache frame range.
Now: If the current frame is out of the cache start/end range, the viewport will show no fluid at all (even if there are cache files present for this frame).
This fix is related / in response to T79423.
Instead of clearing forces at the end of the simulation step, they will now be cleared before writing to them, i.e. at the beginning of a step.
Also cleaned up minor areas that I looked at while making this change.
Yet another update to ensure that pointer variables are always up to date, i.e. those referencing the memory allocated by Mantaflow. Outdated pointers usually show up through flickering in viewport.
In f2b04302cd the pointer update was refactored. It was sufficient to update pointers just in replay mode at the end of a step since the 'ensure()' functions from manta_fluid_API.cpp had their own pointer update call. These were removed in 51f4bee5a5, however, and so in order to still have some sort of update, the given update call needs to be available to all cache types.
A collection of multiple changes that had been living in my stash:
- Use nullptr instead of NULL in C++ files
- Removed unused/deprecated functions from headers
- Cleared animatable flag in cache UI
- Comment cleanups
Use static_cast() where possible and refresh pointers for every frame when in replay mode. The latter is particularly important as this seems to have caused the issue where smoke in the viewport was flickering when loading data from pointers after loading them from disk for the frame before (e.g. when resuming a bake job).
New option that lets users the define the maximum number of fluid particles that will be allowed in the simulation. This can come in handy, for example, to ensure that the particle count will not exceed the hardware capabilities, or to avoid excessive amounts of particles in a scene.
This refactor is in response to reports in which the adaptive domain with noise caused a crash (e.g. T79009). It should also fix issues where the smoke appeared to be cut off when using the adaptive domain together with noise. It is also possible that some of these changes improve the lines issue from T74559.
Changed variable names from mmd, mds, mfs, and mes to fmd, fds, ffs, and fes. The author of this commits lights a candle for all the merge conflicts this will cause.
Added an offset field to control when to load the simulation files. Since this is a very small but helpful addition it is in my view safe to commit at this point of the bcon cycle.
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.
Currently all force effectors can only act on cloth when the force is
perpendicular to the surface. This makes sense for wind, but not for
other forces; and the user may want even wind to have some friction.
This changes effector code to output two force vectors - although
you of course can pass the same pointer for both. The force is split
between the two outputs based on a new per-effector setting.
Differential Revision: https://developer.blender.org/D8017
