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gopherCG
08-23-2007, 05:23 AM
Hi, searched the forums and i'm confused... I'm testing feathers on a torus. Feathers are instanced geometry on a particle emitter on torus surface. It's stuck with goal follow UV. The feathers seem to follow the surface deformations well. OK, I'm using Texture Emission Attr to make some feathers more transparent and eventually disappear (near the head of my bird model). But on this test object, only the particle emitter (display as spheres) picks up the checkered colors. The instanced geom ignores it. I'd also like feathers to decrease in size based on the same texture, but have no idea how to do either.

then the rotation...i'll ask later...
pascal
08-23-2007, 09:41 AM
Hello,

For the color and transparency problem, I believe this is a limitation of maya at the moment.
I think there's no easy solution avalaible yet (see this thread (http://forums.cgsociety.org/showthread.php?f=86&t=498644&highlight=instancer+color)).
Usually you have to create several objects with different opacity/color and use a PP attribute to tell the instancer (through objectIndex) when it has to use wich one...
This can be tedious :)

For the scale of the particles, the best way is probably to create a vector PP attribute and initialize it with values taken from the color.
Then in the "instancer"-tab on the particle shape set the scale dropdown to that attribute...

Pascal.
gopherCG
08-23-2007, 05:45 PM
thanks, i got the PP scale working.

I'll probably give up the opacity PP for instances. And instead vary the denseness of feathers by texture rate.

...but my goal follow and texture rate don't seem to work together, and goal particles only distribute on vertices, not across the surface. How to vary rate then?:shrug:
gopherCG
08-28-2007, 06:27 AM
OK, after days trying...
Using goalU = parentU, let my particles distribute randomly on surface instead of on emitter vertices.

Texture rate works now.
Scale<-rgbPP on instancer gives me size based off texture.

Now to instancer orientation...i'm unsure here...how do I 'shape' the rotation of areas of feathers on my bird w/o manually rotating each feather. I was thinking fields/forces to somehow affect rotation w/o moving the feathers. Other ways?

Here's my config now, which makes feathers appear to stick to a deforming surface (i dont kno why it works tho!!):
Instancer Rotation options:
AimDir: goalworldnormal0PP
AimAxis: uservector1PP = <<1,0,0>>
AimUpAxis: uservector2PP = <<0,1,0>>
AimWorldUp: goalworldtangentV0PP
azshall
08-29-2007, 08:16 PM
Might be worth investing a bit of time to check this handy script out (which deals with instancing feathers/fur) ..

Particle Fur (http://www.highend3d.com/maya/downloads/mel_scripts/dynamics/ho-particleFur-mel-4839.html)
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08-29-2007, 08:16 PM
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