This reorganizes the cloth UI, and changes some of the behaviour to be
more reasonable.
Changes included here:
* Reorganized cloth panels
* Improved some tooltips
* Removed `vel_damping` option
* Removed cloth pinning checkbox
* Removed stiffness scaling checkbox
* Separated shrinking from sewing
* Separated self collisions from object collisions
Reviewed By: brecht
Differential Revision: http://developer.blender.org/D3691
This implements angular bending springs for cloth simulation. This also
adds shearing springs for n-gons.
This angular spring implementation does not include Jacobian matrices,
as the springs can exist between polygons of different vertex counts,
rendering their relationships asymmetrical, and thus impossible to solve
with the current implementation. This means that the bending component
is solved explicitly. However, this is usually not a big problem, as
bending springs contribute less to instability than structural springs.
The the old linear bending model can still be used, and is the default for
existing files, to keep compatibility. However, the new angular bending
model is the default for any new simulation.
This commit makes small breaking changes, in that shearing springs are
now created on n-gons (also in linear bending mode), while n-gons were
previously ignored.
Reviewed By: brecht
Differential Revision: http://developer.blender.org/D3662
This separates cloth stiffness and damping forces into tension,
compression, and shearing components, allowing more control over the
cloth behaviour.
This also adds a bending model selector (although the new bending model
itself is not implemented in this commit). This is because some of the
features implemented here only make sense within the new bending model,
while the old model is kept for compatibility.
This commit makes non-breaking changes, and thus maintains full
compatibility with existing simulations.
Reviewed By: brecht
Differential Revision: http://developer.blender.org/D3655
To find all effectors in the scene, we need to loop over all objects.
Doing this during depsgraph evaluation caused crashes because not all
objects are guaranteed to be evaluated yet.
To fix this, we now cache the relations as part of the dependency graph
build. As a bonus this also makes evaluation faster for big scenes,
since looping over all objects for each particle system is slow.
Fixes T55156.
The modifier is still quite slow; this could be due to caches being written
to a CoW datablock instead of the original one. More investigation is
needed.
The depsgraph was always created within a fixed evaluation context. Passing
both risks the depsgraph and evaluation context not matching, and it
complicates the Python API where we'd have to expose both which is not so
easy to understand.
This also removes the global evaluation context in main, which assumed there
to be a single active scene and view layer.
Differential Revision: https://developer.blender.org/D3152
2.8x branch added bContext arg in many places,
pass eval-context instead since its not simple to reason about what
what nested functions do when they can access and change almost anything.
Also use const to prevent unexpected modifications.
This fixes crash loading files with shadows,
since off-screen buffers use a NULL context for rendering.
Note that some little parts of code have been dissabled because eval_ctx
was not available there. This should be resolved once DerivedMesh is
replaced.
This removes the goal springs, in favor of simply calculating the goal forces on the vertices directly. The vertices already store all the necessary data for the goal forces, thus the springs were redundant, and just defined both ends as being the same vertex.
The main advantage of removing the goal springs, is an increase in flexibility, allowing us to much more nicely do some neat dynamic stuff with the goals/pins, such as animated vertex weights. But this also has the advantage of simpler code, and a slightly reduced memory footprint.
This also removes the `f`, `dfdx` and `dfdv` fields from the `ClothSpring` struct, as that data is only used by the solver, and is re-computed on each step, and thus does not need to be stored throughout the simulation.
Reviewers: sergey
Reviewed By: sergey
Tags: #physics
Differential Revision: https://developer.blender.org/D2514
This reverts commit 5aa19be912 and b4a721af69.
Due to postponement of particle system rewrite it was decided to put particle code
back into the 2.8 branch for the time being.
In addition to pack of conflicts listed below, also had to comment out particle part of new Alembic code... :/
Conflicts:
intern/ghost/intern/GHOST_WindowWin32.cpp
source/blender/blenkernel/BKE_effect.h
source/blender/blenkernel/BKE_pointcache.h
source/blender/blenkernel/intern/cloth.c
source/blender/blenkernel/intern/depsgraph.c
source/blender/blenkernel/intern/dynamicpaint.c
source/blender/blenkernel/intern/effect.c
source/blender/blenkernel/intern/particle_system.c
source/blender/blenkernel/intern/pointcache.c
source/blender/blenkernel/intern/rigidbody.c
source/blender/blenkernel/intern/smoke.c
source/blender/blenkernel/intern/softbody.c
source/blender/depsgraph/intern/builder/deg_builder_relations.cc
source/blender/gpu/intern/gpu_debug.c
source/blender/makesdna/DNA_object_types.h
source/blender/makesrna/intern/rna_particle.c
When updating the max values under stiffness scaling, they clip at the normal stiffness values
as expected, however when updating stiffness values, you could set them higher than the max
values, and the max values weren't updated accordingly. As the stiffness scaling computes using
the absolute difference between the max values and the stiffness values, you got higher
stiffnesses in scaled areas even though your max is actually lower than the normal stiffness.
This diff fixes that behaviour, by updating the max values to be equal to the stiffness whenever
you set a higher stiffness than the max value.
Also, I have initialized the max values to the same as the stiffnesses, as they were previously
just set to zero, and caused the same problem described above.
Reviewers: lukastoenne
Reviewed By: lukastoenne
Tags: #physics
Differential Revision: https://developer.blender.org/D2147
Point cache read code contains checks designed to prevent it reading
stale data when the relevant simulation code should instead compute
the next frame from the previous one. However in some situations like
motion blur subframes the simulation can't possibly do it and just
exits. This causes completely incorrect motion blur at or after the
last cached frame.
To fix, add a parameter that tells the cache code whether it should
apply the checks and exit, or read what it can even if stale (true
means exactly same as old behavior).
Doing this in cache rather than clamping the frame number better in
the caller lets it handle the case of incomplete cache that stops
before the official last frame.
Reviewed By: mont29, lukastoenne
Maniphest Tasks: T49004
Differential Revision: https://developer.blender.org/D2144
This adds the ability for cloth simulations to respect changes in the underlying mesh.
So you can for instance, animate shape keys, armatures, or add any deformation modifiers (above the cloth modifier).
This is mainly useful for (but not limited to) cartoon animations,
where your character might stretch or change shape, and you want the clothes to follow accordingly.
D1903 by @LucaRood
Originally the value was only needed when building the springs,
so a pointer to the input data was somewhat ok. However, recalculating
spring length dynamically requires keeping the actual value around.
The average length is used to adjust self-collision and stiffness
to match mesh density, and in either case considering the always zero
restlen sewing springs doesn't actually make much sense.
The struct_springs variable is also used for other things like total
spring count, so a new one needed for the true struct springs.
This comes out of considering a one-dimensional transition in weight
on a rectangular cloth grid. At the transition face loop, one side
of each rectangular face would be scaled by k1, and the opposite one
by k2, thus turning the rectangle into a trapezoid. Averaging would
be used to choose the scale factor for the remaining two sides.
If Geometrical Mean, i.e. sqrt(k1*k2) is used, it so happens that the
diagonals of the trapezoid also end up scaled by sqrt(k1*k2) compared
to the original rectangle. This means that the same scale factor is
correct for both structural and shear springs, which is not the case
with simple average.
Previously it was all over the place: without a vertex group it was
always enabled, and with it it depended on the Self Collision option
due to a likely editing mistake. Now it should be in sync with what
disables the fields in the UI.
The verts->shrink_factor field is changed to just cache the vertex
weight, with the shrink_min/shrink_max interpolation done later.
This is because cloth_apply_vgroup only runs if there are vertex
groups, and thus the factor may not update after property changes.
In addition, bending springs are now also affected by the shrink
factor to avoid visible distortion in object shape at high shrink.
