View Full Version : rigging a bow

03 March 2006, 05:05 PM
i need some advice here.

Ive modelled a bow with its string. I want the bow to deform correctly when the center of the string is pulled (ready to fire!)

Now my problem is how to set it up. I thought about bones and ik for the bow and maybe spline ik for the string, but with no luck so far...i also thought about morph targets for the string (because both the string and the bow need to remain their length, besides a little stretching of the string)

If you're still with me, how would u do it??? I'm confused...

03 March 2006, 09:18 PM
What about a series of IK and bones? This is tough to explain so in it's most simplified form...
create a joint from the bow grip to the top tip
create a joint from the bow grip to the bottom tip
create a joint from the top tip to the center of the string (where the arrow notches along the string)
create a joint from the bottow tip to the center of the string
add ik handles to each of the bones....
create a transform node that is at the midpoint of the string (where the arrow notch is)
parent all your ikhandles to the transform node you created....
pointConstraint each of your "bow string" joints to the bow handle tip joints.
now when you translate the transform/control back you will see the bow joints arc down and the string joints arc back.

you would have to expand on this theory/idea for creating an actual bend in the bow, but maybe this can help get you started?

You could also use something like a blendshape setup. use a pointOnSurfaceInfo node to track the end of the bow (where the string attaches) and use that as your point to constrain to for your pointConstraint of your string joints.

This exact same thing could work with a bend deformer as well....lots of options...just depends on what you need it to do..

03 March 2006, 06:43 AM
now thats an explanation even i understand. sounds good, i give it a shot...

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