[Bf-committers] Durian/Hair Troubles

[bjornmose]

Well kept building 2.5 every now and then ..
May be I can give some hints on physics solvers ?
Joe may want to ask me .. ( using  ^this^  email  in private )
other than that .. I'll try to squeeze some time out off my schedule to 
investigate the given files.
BM
P.S. 2.5 is going amazingly well, respect!

Campbell Barton schrieb:
> Over the past weeks we have been attempting to get hair working for
> all our shots.
>
> So far Joe has been working on changes to the solver code in our own
> branch but the results solve some problems while causing others (Im
> not sure on the details).
> Joe says the problem is the goal code, which is a little hackish, and
> the bending springs don't work right for hair.
> so it would be a real help is dev's who are familiar with these
> problems can investigate.
>
> I haven't been involved in the hair solver side of things, mostly just
> making sure its possible to run the simulations on proxies on our
> linking setup, testing and setting up bakes for our shots, have cache
> save/load etc.
>
> At the moment it would even be good to see a mediocre hair sim even if
> their are intersections with the head.
>   
>> >From tweaking the settings I had trouble even getting this, though its
>>     
> possible that the problem with my settings.
>
> Would greatly appreciated if any developers have time to look into this.
>
> Notes:
> - can test in trunk or render branch, give different results but
> neither are great.
> - collision is off in this file, seems very tricky to have working
> stable, (sintel's low poly head mesh is a collier).
> - try run the bake on 2-3 sec for fast updates (Brecht has done some
> work on realtime redraw's but not ready to commit)
>
> Heres a blend file with Sintel's hair and the animation (1.0mb)
>  http://durian.blender.org/wp-content/uploads/05.8b.blend
>
> Heres a video of what I managed to get so far (2.0mb)...
>  http://durian.blender.org/wp-content/uploads/05.8b.ogv
>
> Here are the settings used in the animation...
>     psys.cloth.settings.quality = 30
>     psys.cloth.settings.structural_stiffness= 12.0 # good overall
> value to control stiffness, 12 is needed for running up stairs
>     psys.cloth.settings.pin_stiffness = 0.5 # above 0.6 can become unstable!
>     psys.cloth.settings.bending_stiffness = 80.0
>     psys.cloth.settings.spring_damping = 30.0
>     psys.cloth.settings.air_damping = 2.5
>     psys.cloth.settings.mass = 0.015
>     psys.cloth.settings.internal_friction = 0.1 # 0.9 makes hair too symmetrical
>     psys.cloth.settings.structural_stiffness= 60.0
>
>