Research Document
Project Huldra - Integrating 3D-Characters
for Film
link for RD peasant village: http://gscept.com/index.php/sp2010/C23/
Muscle Rigging
To get good looking deformation during this project we
thought it would be best using a dynamic muscle-rigg using Maya
muscle system, with blendshapes as opposed to regular smooth
skinning methods we’ve grown custom to use in previous projects.
We’re going to use a skeleton model mesh (from here on let us
call it bones) that we will fit into our character, these bones will be
driven by Maya joints. NURB sphere will then be placed and sculpted
to some degree of anatomical correctness, to shape the muscles. The
muscle system didn’t mind whether it was affecting a polySurface or a
NurbSurface, but NURB sphere did make for a good candidate to
simulate muscles and was used in all tutorials I could find.
After the bones are rigged, end point and start point of all
mucles constrained to follow the bones. One starts to paint weights,
much like when working with smooth skins.
http://accad.osu.edu/~smay/Human/human.pdf - 1997 Paper presented at Siggraph
http://people.rit.edu/dpalyka/Maya%20Muscles.pdf - More on creating multi-bellied muscles
http://images.autodesk.com/adsk/files/mayamuscleadvancedtechniques2011.pdf - Autodesk
Tutorial on the muscle rigging workflow.
Modeling
Blendshapes mesh
The blendshapes we willl use on the character will only be on the face and maybe on some parts of
the neck. So using the hole body when making blendshapes seems unnecessary. I found a short
tutorial on the matter by digital tutors on youtube. In the tutorial they detach the head and duplicate
it. Then reattach the original head again. This will cause the vertices to have the same name, without
this step maya would notice the faces missing on the duplicated head and refuse to make a
blendshape.
link http://www.youtube.com/watch?v=8WoY-axxUt4&list=FLHvpHO_Wl0Jqcb7M_o1jtOg&index=2&feature=plpp_video
Blendshapes displacementmap
The mesh blendshapes alone won’t sell the character. While using your facial muscles there tend to
create small wrinkles, to do this we will use blend shape with displacementmaps on top of the
regular blendshape. I found some tutorials that blended normalmaps but none that used
displacementmaps. Björn Arvidsson had invented an own technique to blend displacementmaps and
he was kind enough to show me how.
1. Original displacementmap
2. Blendshape, with orginal displacementmap pluss small changes.
3. A pluss minus average with subtract to get the differense between the two displacementmaps.
4. Multiply divide nodens input comes from 3. which has the difference between the two
blendshapes. This node controlls the weight between the original and the new
displacementmap.
5. Plusminus average with sum. Orginal displacementmap and changed displacementmap.
6. A ramp with one color that’s connected to 5. which is connected to a displacement node
that’s connected to the original mesh.
Then I will connect the multiply divide node to the weight of the mesh blendshape. And presto!
blendshapes with displacementmaps.
Map format
The format that Maya likes the most
seems to be .map to create this I will use
the command prompt and an easy script.
imf_copy imagename.type imagename.map this
will create a new file in the directory
where the original file is. The new file
can’t be opened in photoshop. But maya
seems so know what to do with it.