This is a regression in rB4f1c0a1 which only allowed cutting haior at the
second segment only, while there is nothing wrong with cutting hair at the
first segmewnt.
This completes twist feature, which is now possible to also control by
texture. Since textures can not easily contain negative values as well,
same trick with 0.5 neutral as vertex groups is used.
All in all, this twist features allows to do following things.
Original hair:
{F2287535}
Hair with scientifically calculated twist value of 0.5:
{F2287540}
And we can also twist braids in opposite directions dependent on left/right
side:
{F2287548}
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.
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.
Children where always getting at least one segment of fixed length...
Now fully hidden ones (zero length) get no segment at all.
Note that even very short ones keep getting one 'unit' length segment - would
rather avoid changing that at this point, given how complex children
particles 'length' can get with all kind of modifiers... Think we can
live with that for now anyway.
mode.
This was caused by variation of the number of keys on child hairs due
to shortening of hair curves based on euclidian distances. The other
kink modes also shorten hairs, but use the parametric distance instead,
which does not vary with deformation of hairs.
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 contains a few pieces of code for a future "modifier" system that
would allow more flexible combination of effects. Eventually a node
system is the way to go, but the current code makes that impossible.
