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View Full Version : help with bones and IK i think? (newb)



HailStorm
06-28-2004, 01:36 PM
hello

I'm trying to make the string of the bow bend when i move the left bone which i think I've done but not correctly

but i want to have the top and bottom of the string to stay inside the bow, when the string moves it moves the whole string

i will post a picture and the scene file so you know what im talking about

this is my first time trying to use IK which I'm not even sure if i should be using it for this
thanks

HailStorm
06-28-2004, 01:38 PM
Here is a screenshot

I have highlighted the problem
the bits circled in red should stay in place where i circled in green
hope you understand
thanks

omeone
06-28-2004, 05:07 PM
looks like an interesting problem...
but would be much easier to do with morph targets I think
1 morph at stretched position and one at normal postion

with morphs you can also use negative values... so that would allow you add some after-shot 'twang' to the bow string.

omeone
06-28-2004, 05:20 PM
here you go... load the scene and hit play.

have a look around for a basic morphing tutorial
if you are not too familiar with them.

If you look under the deformations tab of the Object Properties
you'll find the Morf mixer Deformation has been added

double click it to see how to control the morph amounts

hit the graph editor button on the morf panel to see the keyframes

Dodgy
06-28-2004, 05:58 PM
I would use 3 bones, one at each end and one in the middle. Or you could use just one with a weight map which just covers the points at the centre of the bow string, there being just points at either end and at the centre. The string will stretch between the bones as the middle bone moves back. I used this set up with dynamic parenting to make a bow. No need for Ik or morphs.

omeone
06-29-2004, 02:10 AM
A single bone and weight map is probably easiest for the string, but when it comes to deforming the whole bow, I think one overall morph target is much easier.