Syncing eyebrow movement with particle hair? (-big- problem)

I’ve run into a little snag on a project I’ve been working on for some time. In a human head I’m trying to rig, I am unable to figure out how to sync the movement of the eyebrow with the eyebrow hairs themselves. :confused:

Here’s what the wireframe looks like just to give you some idea of what I’m talking about: http://i68.photobucket.com/albums/i9/dolanfitzroy/brow.jpg
The high detail of the eyebrow emitter mesh is absolutely necessary. I’m reproducing something very very specific, and I realize I could solve my problem by simply making the emitter the same resolution as the head… but that would completely ruin the whole project. (Hard to explain)

Okay, I’ve been mulling this over in my head for a week. I’ve come up with a number of solutions, but each of them seems to run into a brick wall…

Solution1: Use an armature instead of shape keys.
Problem: I can’t recreate the necessary movements of the eyebrows with an armature, plus the weight painting would be next to impossible to perfect with the high poly count of the emitter.

Solution2: Use shape keys. Create the necessary shape keys on the head mesh, copy the head mesh and remove everything but the eyebrow area. Then apply 2x subsurf to this mesh, and turn it into an emitter. (requires doing all of the particle-related weight painting again, but it seemed like the best idea)
Problem: Copying the head mesh and deleting the unnecessary vertices worked fine, the shape keys were preserved… but as soon as I applied 2x subsurf, the shape keys go bye-bye. :eek: I was so sure it would work too…

I’m particularly fond of Solution2… I’ve had a few other ideas, but they’re all extremely far-fetched. I think I could make solution2 work… if somehow I could apply subsurf to many many copies of the object, each representing a different shape key… and then somehow combine them back together…
Does anyone know how to make separate objects into shape keys of a single object? I know it can be done… I’m just not sure if it can be done easily in Blender.

I usually manage to intuit solutions to my blender problems before I get around to posting here, but this one really has me stumped, and I have only a limited amount of time to complete it. If you can help… …well, I’ll just have to worship you, won’t I? :smiley:

If your shape keys were ‘driven’ by bones by some object/bone this wouldn’t really be a problem. However, if you are just animating the shape keys of the face manually (i.e. using the sliders or editing the ipo curves of the keys to animate the face), then you’ll have to try doing it another way.

VERTEX PARENTING

  1. Be in object mode. Firstly deselect everything.
  2. Select one of the eyebrows
  3. Now with that eyebrow selected, select the head mesh
  4. Press the TAB key to go into EditMode, deselect all vertices
  5. Select only the vertices of the eyebrow area on the head
  6. Press Ctrl-P
  7. Repeat for other eyebrow

Aligorith

Thanks loads. I’ll give it a try and let you know how it goes.

I decided just to force myself to work through it instead of just sitting on my tookus thinking about it, and things sort of fell into place. I’m making duplicate shape keys for the eyebrow objects. While this was my first idea, I had completely disregarded it because I thought it was impractical. Guess not though, once I actually dug in.

Anyway, thanks Aligorith for the info on vertex parenting, with that I can parent the curve guides to the head. so they move along properly (another problem I hadn’t even begun to tackle yet)

Hrm… well, it all seemsed to be going so well. I did a test animation of the eyebrow moving down, and all looks good, aside from the fact that the hairs seem to disappear and appear randomly as it moves. Possibly some option in the particles dialogue that I’m overlooking…
Anyway, here’s the animation:

http://www.youtube.com/watch?v=dVKNvhr1BtM

Notice how, especially near the top, hairs just pop in and out of existence. :confused:

Most likely some mesh intersections are going on. If you used shape keys, maybe adjust the keys in such situations…

Aligorith

Well, as a note for any other scatterbrain like myself who comes across this problem in the future, the hairs were flittering in and out of existence because I had even distribution enabled.