CGTalk - WIP : Robot Bones Help!

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mecha

01-26-2003, 01:05 PM

Hi All,

Need some help with my first serious C4D model. I am building a clunky robot which I want to animate using Soft IK.

After building a basic structure for the legs and feet, I attempted a test Soft IK set up to make sure I was on the right track, and ofcourse I have hit a brick wall.

Here is the untextured model and bone set-up : http://www.mechahost.net/leg.htm

I have rigged up the model a-la-Mime tutorial and set Claude Bonnet Vertex Maps, but need to know how:

1. To place contstraints on the Thigh and Shin bones to only rotate forward and back, not side to side? I tired using the LIMIT paramteres but dont seem to have any effect.

2. To set the bones so the foot can be rotated left and right, without affecting the Thigh and shin?

I guess im asking for the best approach for getting my Robot legs to work. Any advice would be great and I promise to post up my progress as I have sponged so much info of you kind folks it's time I gave a little something back!

Thanks for any help.......:thumbsup:

wuensch

01-26-2003, 01:36 PM

---the limits are heavily affected by the strength setting in the anchor tag. make it higher.

Of course a robot is not good with the defaults of SoftIK, since i woul expect it to deform anything but soft.
You will have to strictly separate the Objects that go with a certain bone.
RTo be honest, i would not set up a robot with bones.
It makes more sense to group the single Obkects in sense-making units ,and use the Objects themselves with IK (or maybe soft-IK if possible) rather then deforming something with bones that is not supposed to be deformed and then trying to get out the deformation-- if you know what I mean--
A robot is certainly the most unorganic charctertype I can think of ;-)

Olli

Srek

01-26-2003, 01:38 PM

Hi,
first of all don't use bones. You have a model that is in no way flexible, so using bones will give it the wrong look. Soft IK works just as fine with any other object, not only bones. Split your legs in seperate parts and control them directly with Soft IK.
Since it is a robot i would set some limitations (as the Pitch and Banking of the ankle) hard by using XPresso. You have to increase the Xpresso Tags Priority so it will override the Soft IK.
If you run into problems with the rotation (will happen in the Foot area) try using Null objects to give the object a prerotation of zero (much like the zero bones).
Try working more with Limits then with rest rotation and a low strength on the effector. The higher the strenghtes are the higher the propability of fast and unwanted roations/movements.

Hope this helps
Srek

Srek

01-26-2003, 01:53 PM

Have a look here (http://www.bonkers.de/download/rigidsetup.c4d) for a simple example.
Regards
Srek

mecha

01-26-2003, 02:27 PM

hey all,

thanks for the tips.

The idea of using bones & soft IK was so I could get nice secondary movement. Never really considered a non-bones approach to character animation.

Maybe my laziness is the problem and I should just FK the whole thing and posemix or pos2pose animate the bot.

Any more tips out there?

Srek

01-26-2003, 02:32 PM

Hi,
why not use Soft IK? It works perfectly for any object, not only bones.
Please keep in mind that bones are only deformers you don't need them if you don't want to deforme something.
Regards
Srek

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