repurposing character rigs?

[markb]

I would think within a procedural workflow like Houdini's, one could set up a scalable, reusable bipedal rig. No? Once a fully working rig is built, could I not simply set things up so that control curves and joint pivots could be moved around to fit new, differently proportioned models and then work through re-capturing manually?

I recently watched a little demo in Blender where this was done. I'm not used to this kind of freedom in Maya.

I'm a new Houdini user, trying to wade my way through learning the software and evaluate if it's the right direction for my personal project.

Thanks!

-mark

[abvfx]

Well, the Autorig tools are there in 9.5 and up. You could use them, or build your own.

Personally i think they add to the weight of the rig because everything can be edited at every stage of development even when in full animation.

Plus i still have the mentality, at least when it comes to rigging, is get it right first time.

So i think the best approach would be to write tools that do alot of the leg work for you.

Eg. I spent a while looking at the best method for creating a spline IK for a back setup. Once i found the perfect setup. The best step forward it to create a tool that can do all of that legwork in one go.

Its a toolkit, basically. enabling you to waste the least amount of time possible. all it would do is create and connect the nodes in the required way, whilst still being editable and light.

and you can use it on whatever joints you want .

You could do this for alot of rigging setups, movable pivots, match FK to IK, match left arm to right arm, custom FK IK setup. find out what works for you then make a toolkit so you don't have to spend the same amount of time creating it the first time round.

[markb]

Hey Phrenzy,

Thanks for the quick reply! I remember seeing your torso rig experiments. I can understand why a custom autorigging tool would be the smartest way to go.

I also see how it would be difficult to simply "move bones around" with a bone based vs a joint based system.

It was too much to hope for the miracle of moving bones and controls around to fit new characters. New autorig it is then (if I have the time to put into learning it) yet again and in a new piece of software.

Thanks again!

[abvfx]

Cool, but like i said autorig tools add alot of weight to the character.

It would be better to find what setup works for you and then make tools to speed up the process.

What you talk about in terms of "moving bones and controls to fit new characters" is there. Load up houdini, click the AutoRig tab and Ctrl Click on the Biped Auto Rig. Once you load in your character you place the controls to fit within your character then you hit the Make Rig button... and boom its there.

But for me its too slow. It would be faster to create the bones and then select the ones labeled "spine" and click make stretchy spine button and thats done. then select the legs and hit the "Create leg setup" button. Its fast, its still procedural because all its doing is creating nodes and its light. The only downside is you still have to make the bones, but that isnt too difficult.

Hope this helps.

Right now, im looking into learning either Hscript or Python to make such tools. I think Python would help me out better in the long run but looking at the documentation at the moment is a little bit confusing and hard to find alot of commands.

[markb]

Ah, yes, sorry, that's what I meant: A tool that rigs a set of joints for you.

Still, there is the learning overhead of how python plays with Houdini while I am still trying to cram down some of her more fundamental concepts. I will work to climb those walls first. I can't imagine tools would be too big a stretch if I'm already comfy with python.

Thanks a lot for your help!

Cool, but like i said autorig tools add alot of weight to the character.

It would be better to find what setup works for you and then make tools to speed up the process.

What you talk about in terms of "moving bones and controls to fit new characters" is there. Load up houdini, click the AutoRig tab and Ctrl Click on the Biped Auto Rig. Once you load in your character you place the controls to fit within your character then you hit the Make Rig button... and boom its there.

But for me its too slow. It would be faster to create the bones and then select the ones labeled "spine" and click make stretchy spine button and thats done. then select the legs and hit the "Create leg setup" button. Its fast, its still procedural because all its doing is creating nodes and its light. The only downside is you still have to make the bones, but that isnt too difficult.

Hope this helps.

Right now, im looking into learning either Hscript or Python to make such tools. I think Python would help me out better in the long run but looking at the documentation at the moment is a little bit confusing and hard to find alot of commands.

Ah, ye

[michael]

I've posted a bunch on this topic in the past...

having made an autoRig for Houdini I can tell you it's not that hard - not as easy as in Maya with it's script editor that can echo all your actions, but hscript is good enough.

some quick points:

nested HDAs are VERY expensive

the instict to use lots of nulls as internal, hidden controls is also expensive

if you have a rig and want to reshape it to a new mesh it's actually really easy - you just need to find the roots of your IK and the 'effectors' etc and move them intelligently set up a simple leg and poke around - you'll see the tricks pretty fast. you can 're-eneter' the bones state and change the length and rotation of bones this way also.

[abvfx]

markb: yeah thats what i am trying to overcome aswell. Im not a programmer, and am not intending to be one. But im not an idiot , i know the benefits of having scripting abilities. If not to make oneself more marketable then to perform certain repetitive tasks in the blink of an eye.

I am still debating whether or not to learn python over hscript. I know python is more powerful but im only interested in performing tasks that utilize houdini's nodes and parameters. And from the outlook hscript seems much simpler and easier to use.

But its also older and i dont the the future of this scripting language.

But then i just found this quote.

"We are not switching from hscript to python, but simply incorporating python."

Edited March 23, 2009 by phrenzy84

[thekenny]

I've posted a bunch on this topic in the past...

having made an autoRig for Houdini I can tell you it's not that hard - not as easy as in Maya with it's script editor that can echo all your actions, but hscript is good enough.

I've been thinking that if I ever get the chance to do it again I would make OTLs for all the different pieces and they make the rig as non-otl pieces in a sort of make process. Yes that negates some of that fancy fun that OTLs give you but as Mike indicates it will save you some of the overhead. It's about the speed and the easy to get it done. Having all those dependences is a bit heavy and complicated. In the end all you need to do is store the key locations/orientations and consider the construction from point A to B. If you can build it once, you should be able to build it again and again. Need a revision then put the character back in the garage for a build and modify the base and go again. If you name things correctly and keep the hierarchy around the weighting will work, but really new bones can be added seemlessly now anyway. You need the top level controls and speed and that should give you the best of both worlds.

You could also keep the "published" rig stripped down and keep the pure rigging one nested to allow for easier modification but I would still strip as much out as possible. That is unless you can get away with the OTL in certain areas. There might be place where you need it, but others you can do with out.

Just thinking out loud... I have to finish my model first before I can rig it

-k

[edward]

My personal experience has been that Python is a lot better for everything except simple scripts. For parameters, I still use hscript expressions. But of course, "hscript expressions" is not exactly "hscript". From time to time, I find something that is in hscript but not in Python and I just use hou.hscript() as a bridge.

[michael]

@ kenny

yep - as you know that's what we ended up doing - I had a series of scripts that would 'flatten' the rig to removethe nested HDAs...

one tip that I would stress: don't build this kind of thing /during/ production - it gets hard to keep up

[thekenny]

and there you go!

-k

@ kenny

yep - as you know that's what we ended up doing - I had a series of scripts that would 'flatten' the rig to removethe nested HDAs...

one tip that I would stress: don't build this kind of thing /during/ production - it gets hard to keep up