View Full Version : Questions about rigs in blender

03 March 2003, 07:52 AM
I am really interested in getting into blender, from what I've seen its a very competent program (and free to boot). Anyway, I was wondering about rigging in blender.

At school I used Maya and when I set up rigs I use a lot of control objects to make using the rig easier. Is this possible to set up in blender? Also things like "Set Driven Keys" (ie, a sliders that control things like closing fingers etc).

As you can see I have very little experience with blender so I don't know what it can do although I am ready to be shown (anyone got any links?). Alos if anyone knows of any indepth rigging tutes for blender I would be really interested.

03 March 2003, 12:41 PM
Here's a rundown of Blender's rigging/character anim capabilities...

1. implements both ik and fk in the same rig

2. allows bones to be parented/contrained to other bones within the same armature or external objects such as empties/lamps/meshes

3. contraints include:
- copy location (copies location of another object, x y and z separately selectable)
- copy rotation (currently only copies full rotations of other objects)
- ik solver
- track to (points the bones y-axis at the target and tracks it)
- action (use of this contraint can activate saved actions over a specified range; can be used to deform a muscle when the bone is rotate, etc.)
- null

4. The strength of these contraints can be animated; eg. you can have two Copy Location contraints on a hand rig and animate their relative strengths in order to have the hand switch between two distinct "lock" locations; eg. you can turn an ik solver on and off to switch between ik and fk on a chain.

5. Objects can be parented to rigs on an object-per-bone basis to do mechanical, rigid style animations; or by linking different parts of a mesh to different bones for smooth organic deformation. (I've found the weight painting tools for this to be kludgy and difficult; I prefer to use the smooth deformation with a well thought out subsurface cage.)

Keyframed rig sequences may be easily stored as Actions, which can be put together in the non-linear editor, with action blending, ease-in/out, support for walkcycles along paths.

Commonly requested items:
1. rotation limits
2. control sliders
3. better smooth mesh deformation

Rotation limits have been requested for along time. I do not know the technical feasability or the current status of implementing this feature in the Open Source release.

It would seem that the control sliders would not be that hard to implement, especially in light of the NLA system, and I wouldn't be surprised if someone in the open source community is attempting to do them.

Better smooth mesh deform. My gut tells me that this will be a tougher one to work on. I haven't seen anyone mention that they are fixing it, and I try to keep up with what's going on. As stated above, I use subsurfs almost exclusively for character work and they perform quite well.

Hope this is a good enough overview for you to make an evaluation.

As I'm not really up on the current state of Blender's tutorials, I'll let someone else with better knowledge point you in the right direction.

03 March 2003, 01:28 PM
Well, you can start with these:

This a more detailed and in depth tut about Armatures:

If you want to learn Blender's NLA, go there:

and a nice walkcycle from the same guy (malefico...) :

Hope it helps...


03 March 2003, 05:35 PM
Originally posted by DrAdamDinosaur
Also things like "Set Driven Keys" (ie, a sliders that control things like closing fingers etc).

*Cough *Cough. Good that you asked about the subject. Rigging is my strong point in Blender. (I'm writting a tutorial on character setup that I guarantee will cause some mayor stir)

About your question: Yes. Inside Blender are called Relative Vertex Keys (RVK) and there are to ways to handle such things.

First, the default blender way... it is a little different from Maya in that instead of using sliders you draw a bleizer curve along the horizontal axis in a special window. Somehow it is better than the slider aproach in that you can see in a glance how all the actions of the character interact with each other during the whole animation by just looking at the shape of the curves.

here an example:

and here is the same technique applied to lip sync:

Second, by using the Meloware's RVK Pozer script you can use a GUI with sliders to control the RVK curves, so you only see sliders (ala Maya), and the scrip handles the curves for you.

Best of all, you can switch back and forth between the two approaches.

03 March 2003, 05:40 PM
I think somebody's working on making RVK as asy to use as poses are >> you can use the NLA editor to animate with rvks.

I think this will be a huge improvement!


03 March 2003, 05:50 PM
Almost forgot. There is a third way for handling things like finger clousure that doesn't involve RVK at all. It is done by defining a base pose and them different actions (i.e. closing the fist or raising a leg).

This way is WAY MORE DIFICULT to implement for fine gestures, but once the setup is done you go like the breeze.

Also it is more usefull in the long turm because it allows you to share animation data among diferent characters (that even could be stored in different files). Think of it as if you write an animation/pose library, and them re-use them as the time comes.

*The first and second approaches I gave can' t be used to share animation data among different objects because some technicall tidbits related to RVKs itself.

03 March 2003, 05:53 PM
Originally posted by dani
>> you can use the NLA editor to animate with rvks.

I think this will be a huge improvement!


That is already available, it just takes some magic involving the Oops window. Check out the tutorials on The Blended Planet.

* Edit: Totally missundertud what Dani said. You are talking about MODIFIYING the RVK by using the NLA? Now that would be great to have.

I was talking about modyfiying the RVK and the Poses at the same time but independent from each other, somehow related but no the same thing.

What you said is waaaaaay more cool.

03 March 2003, 03:59 AM
Thanks for the run down and all the links, I'm still mulling through them but I think I'll definetly try the armature tutorial. I would be very interested in seeing the tutorial you are writing when you are finished. One more question about character setup. How does blender handle blend shapes? Can they be done on a per-vertex level or do they have to be done on a per-object basis?

03 March 2003, 04:28 AM
First, let me see if I understand the question:

'Blendshapes' in Maya jargon are the final transformations that you want your mesh to adopt during an animation?

Like, one single mesh of a face with a sad expression, a happy expression, an annoyed expression, etc. etc. etc. ?

If that is what blendshape mean (and I think it is), then those are what within Blender we call Relative Vertex Keys (RVK). They are handled per object on a vertex-per-vertex level.

on other words, to change from one 'blendshape' to the other, the vertex inside an object are re-aranged into a different position, but the total number of vertexs remain the same.

03 March 2003, 01:33 PM
Ok, I think I'm on top of this now. I got a little confused before. RVK's don't work on bones (The aramture) right.... they are vertex specific, right?

Yes, blend shapes are for creating things like face shapes, ie; happy, sad, eyebrow up, eyebrow down etc.

Therefore, and correct me if I'm wrong, I would create my blend shapes with RVK's and my set driven keys (for set actions for bones) with base poses. Can you have more than one pase pose so you can switch between them?

Sorry, getting to grips with a new program is always a little strange. Theres tones of new names to learn for things you have been calling something else for a long time (I had to do this when I went from max to maya as well:))

03 March 2003, 01:49 PM
Originally posted by DrAdamDinosaur Can you have more than one pase pose so you can switch between them?

Assuming you meant "base pose" the answer would be no. There's only one base pose, the rest position.

If you mean something else by "base pose" the answer may be another :D

03 March 2003, 05:02 PM
DrAdamDinosaur, you got it 100% right!!!

About having more than 1 base pose... in theory you only can have 1 BUT in the practice you can have as many as you want.

You create the so-called 'second base pose' as an static action (just 2 of 3 frames long is enough), then when composing your animation inside the Non Linear Animation editor you just activate the 'hold' option for that pose. That effectively overrides the 'real' base pose with the one indicated on the NLA action.

03 March 2003, 05:15 AM
:D Yeah, I meant base pose, just me trying to type to fast becasuse I had to type that post twice.

OK, guess I'll have to learn the NLA system aswell. I find rigging a fun challenge so once I get my head around blender this should be interesting.

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