This feature has been totally broken for a long time. It was added
originally because negative frames were not supported.
Giving simulations (cloth and others) time to settle before animation
starts needs to be solved in a much better and more generic way.
These were used as UI buttons during development. If such parameters are
needed again later they should instead be added in the (now global)
SimDebugData and made accessible with a dev addon or so.
This allows setting a target density which the fluid simulation will
take into account as an additional term in the pressure Poisson
equation. Based on two papers
"Detail Preserving Continuum Simulation of Straight Hair" (McAdams et al. 2009)
and
"Two-way Coupled SPH and Particle Level Set Fluid Simulation" (Losasso et al. 2008)
Currently the target pressure is specified directly, but it will be
a lot more convenient to define this in terms of a geometric value such
as "number of hairs per area" (combined with hair "thickness").
Conflicts:
source/blender/physics/intern/BPH_mass_spring.cpp
This is a bit more awkward for artists to use, but necessary for
a stable solution of the hair continuum calculation. The grid size is
defined by the user, the extent of the grid is then calculated based on
the hair geometry. A hard upper limit prevents bad memory allocation
in case too small values are entered.
Conflicts:
source/blender/physics/intern/BPH_mass_spring.cpp
This is an artifact of earlier attempts to implement velocity smoothing,
but doesn't work anyway.
Conflicts:
source/blender/physics/intern/BPH_mass_spring.cpp
This returns a general status (success/no-convergence/other) along with
basic statistics (min/max/average) for the error value and the number
of iterations. It allows some general estimation of the simulation
quality and detection of critical settings that could become a problem.
Better visualization and extended feedback can follow later.
This is part of the original method from "Volumetric Methods for
Simulation and Rendering of Hair". The current filter is a simple box
filter. Other energy-preserving filters such as gaussian filtering
can be implemented later.
The filter size is currently given as a cell count. This is not ideal,
rather it should use a geometrical length value, but this is too
abstract for proper artistical use. Eventually defining the whole grid
in terms of spatial size might work better (possibly using an external
object).
This implements a penalty force as well as a repulsion force to avoid
further penetration, as suggested in
"Simulating Complex Hair with Robust Collision Handling"
(http://graphics.snu.ac.kr/publications/2005-choe-HairSim/Choe_2005_SCA.pdf)
Friction forces are still missing. More problematic is handling of
moving colliders, when face swap places with the hair vertex and a
collision is missed, putting the vertex inside the mesh volume. Larger
margins might help, but ultimately using Bullet collision detection is
probably more reliable and failsafe.
on itself.
This uses the same voxel structure as the hair smoothing algorithm.
A slightly different method was suggested in the original paper
(Volumetric Methods for Simulation and Rendering of Hair), but this is
based on directing hair based on a target density, which is another
way of implementing global goals. Our own approach is to define a
pressure threshold above which the hair is repelled in the density
gradient direction to simulate internal pressure from collisions.
Description:
--------------------------
Use loose edges marked as seams as sewing springs.
Usage:
-------------------------
All this patch does is set the rest length to 0 and the stiffness to 1 for springs for loose edges marked as seams so that during the cloth simulation they will be brought together.
Example Video:
-------------------------
http://www.youtube.com/watch?v=-Y_bC0gjoM0
Original Patch by thesleepless (+ git patch by codemanx)
Thank you!
Self collision vertex groups enable artists to exclude selected vertices from getting involved in self collisions. This speeds simulations and it also resolves some self collision issues.
Note about long lines: I did not touch to two pieces of code (because I don’t see any way to keep a nicely formated, compact code, with shorter lines):
* The node types definitions into rna_nodetree_types.h
* The vgroup name functions into rna_particle.c
only tags the ID and does the actual flush/update delayed, before the next
redraw. For objects the update was already delayed, just flushing wasn't
yet.
This should help performance in python and animation editors, by making
calls to RNA property update quicker. Still need to add calls in a few
places where this was previously avoided due to bad performance.
to specify different spring lengths.
Implementation is quite ugly because the shape key has to be pulled
through the modifier stack somehow, need a more flexible data mask
system to solve this properly.
(commits 27773,27775,27778 by Brecht from render25 branch)
* Effectors now work with hair dynamics.
* Hair dynamics has a new "Collider Friction" parameter that works similarly to internal friction except now all collision objects effect the hair velocity. Useful for quick'n'dirty interaction with objects as the calculations are really fast, but doesn't really take away the need for proper hair-object collisions.
