simple animation question (constraints)


(Galad) #1

I want to lock the feet of my character in place and reposition the body. Is there a way to use constraints (copy location?) so that i can lock the feet, and when i reposition the body, blender will automatically bend the legs as needed? This may be a dumb question, but i’m having trouble searching for it. thanks.


(Gabio) #2

Ik chain is what you’r looking for.
check the example in this .Blend file
The idea is to parent the root of your chain of bones to the body’s chain (the spine) and put the goal of the ik constraint in the foot.


(Galad) #3

thanks that worked. one more thing though…

I stumbled across a way (i think) to constrict the joints to bending at certain angles, for example making the knee bend like a hinge, but i forgot what it was called and I cant find it anymore. I’m not sure what the technical term i’m looking for is so i’m having trouble searching for it.


(Duoas) #4

Blender 2.40 will have rotational range-of-motion constraints for bones, but up till now there is no such thing.

To get a (e.g. knee) to point the way you want most reliably, create five bones:

IK chain: upper.leg, lower.leg, leg.null

and: knee, ankle

Place knee’s root at the joint between upper.leg and lower.leg. Place ankle at the joint between lower.leg and leg.null.

Give leg.null an IK constraint targeting ankle.
Give lower.leg an IK constraint targeting knee.

Don’t forget to Ctrl-N (Recalculate Bone Roll Angles). To animate, move the knee bone out away from the knee joint in the direction you want the knee to point.

Good luck


(Ammusionist) #5

Do you know if this is in the Alpha?


(Fligh) #6

Yes, on all bones in an IK-Chain; Lock and Limit values for all 3 axii (now called DoF Options).

%<


(Ammusionist) #7

DoF??? Isn’t that Depth of Field?

I don’t get it!

(But thinks for the quick answer Fligh%)


(Fligh) #8

Degree of Freedom:

http://www.blender.org/cms/Inverse_Kinematics.663.0.html

We will have to start differentiating between DOF (depth of field) and DoF.

%<


(Galad) #9

Thanks. blender is pretty good except its hard to figure out how do to some things. Maybe someday they’ll get around to making the interface easier for people who are still learning. Cant really complain though cause it’s free :wink:


(Ammusionist) #10

I have a theory that versatility is inversely proportional to useability.

On the one hand, a single red button is real easy to use, but it doesn’t do a great variety of stuff!

Blender on the other hand, is incredibly versatile and intricate so therefore is does take some learning.

The best thing I can advise is - Stick with it - it’s worth it!


(MrMuscly) #11

As soon as you run in to trouble there’ll always be The User Guide to refer to, and when that one doesn’t solve your problems there’s always Elysiun ^^

Just to make sure you know ^^