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Facial Rigging Q&A

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Facial Rigging Q & A

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As H12 is nearing our systems, there is one feature in particular that has me quite excited. It is one that wont get a lot of attention because its a relatively technically small amendment but one that will change a process and workflow. Pre-Selection highlighting will completely change how one animates.

So with animation being much easier (no more trying to select super thin handles) rigging is one thing im looking to get back into. Especially facial rigging.

There is relatively little information on facial rigging with Houdini. You can find bits 'n pieces here or on SESI's own forum but its still very much either something that you do based on the techniques used in other software or it takes a lot of time and trial and error.

I would like this thread to be a sort of hub to the main questions concerning facial rigging. Not just for my benefit but for future visitors/users. I imagine there are a lot of solutions to the problems that will be discussed and I hope this thread can serve as a place for them.

Since this is a topic i have a lot of interest in i will post a lot of my experiences too.

Any/all contributions welcomed. (Even if you don't have the answers :))

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Related Threads

Importing External Blendshapes

On-Face Controls

Facial Rigging in Houdini with Bones

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Q. So i will kick things off with a question i have. I imagine when rigging the face that one isnt working with the entire model (body). So how would you be able to rig the face and then to bring in the full model & body rig and transfer the weights.

Is it something as simple as using an attribute transfer?

Edited by phrenzy84

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Hi Andrew,

It should be even easier than an attribute transfer. But first, yes an attribute transfer should work, as long as you create a primitive group for the head on the full model that contains the exact same primitives as the stand-alone head model. I was able to use this technique to create blendshapes from a number of shape heads to a target full body model. So yes that should work. However, that being said, if you're doing the full rig in Houdini, you can simply do the head rig, and then connect it to the body in SOPs (with, say, a fuse SOP or something). Since you have the full constructive history in there it shouldn't matter when you rig the face. You can do the face, fuse it to the body, and then rig the body. I hope this helps!

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Thanks Evan. I might try the first method since the full body model is done, there is no need to do any more geometry editing. I will try in the future to finalize the head model and body separately (making sure the seems line up) and see how that goes. It sounds like a more flexible workflow.

I think also in my case a simple visibility sop might just for the head/neck might do since the base mesh is complete. A there was a thread here about capturing based on selections that seems very relevant.

Capture Based on Selections

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Sounds cool! I haven't played with that technique, but seems like an interesting approach. There's a million ways to do things, really, which is why I like Houdini. You just have to be clever and open your mind about how you approach problems, sometimes going completely against what's been pounded into you via standards from other packages. Keeps you on your toes :)

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So after the christmas break ive had some time to mess around in H. Got a good workflow for blendshape, only model the shapes on the head and the have the applied to the body also being able to paint weights on those modeled shapes so i can split or taper them if you have read Stop Staring.

I will probably do a video of the workflow once i model a few shapes.

One thing im wondering is there any way to speed up a lattice SOP in points mode?

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One thing im wondering is there any way to speed up a lattice SOP in points mode?

You can try to use pt groups and isolate what it is you are trying move with the latticeSOP. I haven't tried H12, so I'm not sure if the new geometry structure would be as slow as previous versions, there might be some speed ups if once the pts are declared and set to be used in the sop itself. otherwise, do it in bones. The blendSOP (i think it is still called that) has/had some good toggles for speed increases and they do work as long as your input isn't changing then that kinda negates what the toggles could do for you. You also should try as much as possible to keep the blendSOP above your deformSOP. Any deform after the deformSOP will slow you down.

I would personally avoid the lattice and use blends then bones.... wires maybe... depends on what you are doing.

-k

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Instead of a live Fuse sop which you would have to wrangle precision errors, try prepping the body mesh so that the head geo has verts 0-100 and the rest of the body 101+ .

That way you can blendshape the rigged head straight into the body. You could rig a static head that doesn't move from origin - gets blendshaped before the deform sop.

And as phrenzy recommended, Stop Staring is a great book for a Viseme based facial system.

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Guest mantragora

So after the christmas break ive had some time to mess around in H. Got a good workflow for blendshape, only model the shapes on the head and the have the applied to the body also being able to paint weights on those modeled shapes so i can split or taper them if you have read Stop Staring.

I will probably do a video of the workflow once i model a few shapes.

One thing im wondering is there any way to speed up a lattice SOP in points mode?

Hi Andrew.

Any news on this workflow video ? I would love to see this in action !

Edited by mantragora

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Still working on rigging solutions on and off. Finishing a character off and understanding SSS here > http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=26105

But on the rigging side ive been looking into sticky controls, think ive found decent solution but it has its kinks that i havent spent alot of time to fix. Trying to contact arctor but thats a hard man to get a hold of :). You can take a look here though.

http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&p=119510&highlight=#119510

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Guest mantragora

How far have you dived into "Stop Staring" book ? Which edition ? 2nd ? 3rd ? I'm thinking about going thru it myself and I'm just curious how much time it took you to get some working results in Houdini ?

Edited by mantragora

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