The idea is to give a control over direction of twist, and maybe amount of
twist as well. More concrete example: make braids on left and right side of
character head to be twisting opposite directions.
Now, tricky part: we need some negative values to flip direction, but weights
can not be negative. So we use same trick as displacement map and tangent normal
maps, where 0.5 is neutral, values below 0.5 are considered negative and values
above 0.5 are considered positive.
It allows to have children hair to be twisted around parent curve, which is
quite an essential feature when creating hair braids.
There are currently two controls:
- Number of turns around parent children.
- Influence curve, which allows to modify "twistness" along the strand.
The check to see if `use_advanced_hair` was enabled was actually in two places
(render panel `draw` function and physics panel `poll` function). As these
properties are only in one place now the check in `draw` isn't needed anymore.
Related: T53513, a6c69ca57f
Technically this was introduced in 01b547f993 when
exposing size and randomness for particles.
This "fixes" makes sure particle size and size randomness is always in the
Render panel when it affects the particle system (i.e., always unless using
advanced hair or hair that is not rendering groups/objects).
This allows a duplicator (as known as dupli parent) to be in a visible
collection so its duplicated objects are visible, however while being
invisible for the final render.
An object that is a particle emitter is also considered a duplicator.
Many thanks for the reviewers for the extense feedback.
Reviewers: sergey, campbellbarton
Differential Revision: https://developer.blender.org/D2966
Engine is not stored in WorkSpaces. That defines the "context" engine, which
is used for the entire UI.
The engine used for the poll of nodes (add node menu, new nodes when "Use Nodes")
is obtained from context.
Introduce a ViewRender struct for viewport settings that are defined for
workspaces and scene. This struct will be populated with the hand-picked
settings that can be defined per workspace as per the 2.8 design.
* use_scene_settings
* properties editor: workshop + organize context path
Use Scene Settings
==================
For viewport drawing, Workspaces have an option to use the Scene render
settings (F12) instead of the viewport settings.
This way users can quickly preview the final render settings, engine and
View Layer. This will affect all the editors in that workspace, and it will be
clearly indicated in the top-bar.
Properties Editor: Add Workspace and organize context path
==========================================================
We now have the properties of:
Scene, Scene > Layer, Scene > World, Workspace
[Scene | Workspace] > Render Layer > Object
[Scene | Workspace] > Render Layer > Object > Data
(...)
Reviewers: Campbell Barton, Julian Eisel
Differential Revision: https://developer.blender.org/D2842
Physics panels are not all back, and the material related panels (e.g.,
hair render panel) should go be changed since there should be no
material for those.
Although this wasn't so obvious since it
only showed up for factory settings and in the preferences window.
Panel display order depends on registration order,
Sorry for the noise. On the bright side we no longer need to move
classes around to re-arrange panels.
As suggested by Sergey, do not register those anymore, this way we keep undo step,
but user cannot 'redo' them (does not work, since cached DM in particle modifier data
is not yet re-created by depsgraph update after undo when operator is redone).
UI now has two buttons, one to (dic)connect current psys, the other to (dis)connect all.
Also fixed similar issue with Connect Hair op.
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 is BAD code, but the particle kinking does not make it easy to
write a non-local modifier that requires neighboring positions,
curvature, etc. The feature is needed for Gooseberry.
This adds another level of clumping on child hairs. When enabled, child
hairs chose a secondary clumping target using a Voronoi pattern. This
adds visual detail on a smaller scale, which is useful particularly when
the number of parents is relatively small.
Natural fibres behave in a similar way when they become sticky and
intertwined. Hairs close to each other form a first twisted strand, then
combine into larger strands. Similar features can be found in ropes:
http://en.wikipedia.org/wiki/Hair_twistshttp://en.wikipedia.org/wiki/Rope
Conflicts:
source/blender/blenloader/intern/versioning_270.c
This is an alternative method to the current fixed function with a
clump factor and "shape" parameter. This function is quite limited and
does not give the desired result in many cases (e.g. long, parallel
rasta strands are problematic). So rather than trying to add more
parameters there is now a fully user-defined optional curve for setting
the tapering shape.
This is necessary because the hair dynamics settings are not part of the
ParticleSettings datablock, but part of the convoluted cloth modifier
inside the particle system struct. In the future this will be recoded
properly, but in the meantime presets provide a simple an unobtrusive
way to have reusable dynamics settings for hair.
Conflicts:
release/scripts/startup/bl_ui/properties_particle.py
This helps to create some variation in a hair system, which can
otherwise become very uniform and boring. It's yet another confusing
setting in a system that should have been nodified, but only option for
now (broken windows ...)
Conflicts:
source/blender/blenkernel/intern/particle_system.c
source/blender/physics/intern/BPH_mass_spring.cpp
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
more intuitive.
Also removed a couple of unused or useless features from the UI:
* collider friction is unused and replaced in favor of true collision
* spring damping refers to structural springs (stretch), which is
not noticable in hair due to extreme stiffness atm.
* pressure factors are not sure since this feature is too unstable atm.
Conflicts:
release/scripts/startup/bl_ui/properties_particle.py
Without this the particle system only shows the actual non-simulated
hairs ("guide hairs") during edit mode. These hairs are used for goals
as well, so showing them in the regular viewport is pretty important.
Also the usual hair curves are interpolated along the entire length,
which makes it very difficult to see exact vertex positions, unless
using exact powers of 2 for the segment number and match the display
steps.
Conflicts:
source/blender/blenkernel/intern/particle.c
