hi, I'm trying to rig a games character (low poly) to have basic facial mobility (mouth, eyebrows, eyes). I've used all the available bones for the body and I can't use blend shapes. I'm using Maya 5.0.
Does anyone know any good tutorials for this or a book they can recommend? Advice? heeelp!!
thanks guys!!
hi Aven!
Thanks your a legend!
I should have been clearer though (guilty cringe...sorry) I'm not ALLOWED to use blend shapes. just to make life difficult! Apparently blend shapes won't export to games engines.
I've been told that in 3DS max you can constrain verticies to objects (ie locator) and then paint the weights to respond to the object as well as the bones. but I can't figure out how to do anything like that with Maya. Any ideas?
thanks again!
Some game engines can use any type of animtaion deformer you throw at it though (even dynamics). Quake2 was a good example as it used vert location info. Basically the character was just one big blendshape. I think that Warcraft3 uses the same technique if I'm correct (if someone could tell me I would really appreciate it).
Anyway. Maya can do that multiple ways. Clusters, Wrap defomers, and probably a whole bunch of other ways I don't know of :p
Clusters
Select the verts/edges/faces on the mesh that you would like to bind. The right eyebrow for example. Make sure you are in your Animation Menu Set. With the component selection active, go to Deform>Create Cluster. Just use the defaults, don't bother using the option box. A little 'C' should now be in the center of the selection. All the verts will be 100% bound to the culster, but you can fix that. Select the mesh and go to Deform>Paint Cluster Weights Tool. Go to the Tool window and paint away with whatever setting you need. You can add or subtract or smooth. If you have used any of Maya's Artican tools than you will be fine. If not just let me know. I'm not too sure if that cluster will be classed as an object for your exporter though.
Wrap Deformer
Although this can be fantastic for a lot of areas, it is very loose and can't be edited overly well. Create a mesh that will be your influence mesh/object. Place it around the verts you need. Select the character mesh and then Shift+Select the influence mesh. Move the influnce mesh and change the values in the Wrap Deformers tab in the Attribute Editor (or Channel Box). This is a really good way for setting up simple muscle controls for characters, but it's lack of editablilty will really harm you with facial expressions.
Bones
If the engine can handle enough bones, then why not just use them? Read this tute. It's by some Aussies who won a short film festival last year, so they do know what they are up to :)
http://www.cane-toad.com/tuteRig_Facial.htm
If you have any questions, about Clusters or Wrapping, thenread through the Maya Help File. It is really good and has every single attribute listed as well as it's function.
It just seems really odd that you aren't allowed to use Blendshapes. Once the History has been deleted, it shouldn't really matter as the animation will just remember the vert postions. Oh well. I hope that helped a little. Good luck :D
Okay. Here are some blendshape helpers for Maya.
1. Complete the character with UV maps and rigging. Trust me, this will save you a LOT of time. Do it once. Do it properly.
2. Decide what blendshapes you need. and lay them out on a piece of paper in rows. ie, have all your eyebrow shapes on one row, phonemes on another, other mouth shapes on another. Duplicate the base mesh as many times as you need for the shapes. Duplicate ANOTHER mesh for each row. This mesh will be called eyebrow_target
3. Select each blendshape in a row at a time using Shift+select. With the final selection, select the eyebrow_target mesh. Create a blendshape for the eyebrows.
4. Continue this pattern for all the rows.
5. Select all the blendshape_target meshes at one time and then select the original mesh. Create another blendshape. You should now have a blendshape window with all you shapes set up nice and neatly.
The reason why you have to have those dummy targets that are compounded to the original mesh is so that all the shapes can be blended together. This makes it easier for large amounts of shapes as you can group them in catogories. If you don't have the dummy meshes and you have different groups, then the shapes wont be compouded, they will just be replaced.
You can also blend groups. This is really useful for making a whole head with a tounge and then grouping all the targets. Blend the groups, and you can have multiple meshes blending at once.
Make sure that you name everything really well. It will save you a lot of time and frustration later.
Make sure that you don't make changes to the mesh integrity. ie, don't add in extra faces/edges/verts. It wont be able to blend.
Don't change the pivot point for each mesh. Blendshapes (like morphs in Max) work on moving a vert to it's new place inb relation to the mesh's pivot. This also means that you can't just make the left eye wink, duplicate that mesh and mirror it. The whole mesh will flip due to vert numbering.
I am just writing this up quickly before I go to work, so there aren't any pics. If you need some, let me know.
I'm yet to actually see any really good facial expression tutes. Most just teach you the basics and leave it there.