3D World

Artist q&A

Your CG problems solved

pythOn

If implementing this as part of a Python script you won’t be able to use the ikSpringSolver

command, as this can only be activated using MEL. Instead you can use the following code (see

right) to run a MEL command in Python, so in this case we can evaluate ikSpringSolver.

ExpErt tip

01

WhErE’S thE SOlvEr?

You may be wondering where to find the IK spring solver. As

mentioned, the option isn’t readily available under the IK Handle

tools, so you will need to load it first.

To do this simply execute the following code in the script

editor – ikSpringSolver – simple as that. You will now see the

ikSpringSolver option under the Current Solver drop-down box

inside the IK Handle Tool settings.

02

Apply tO yOur chAin

You can now build your joint chain as you would normally.

To help illustrate the difference between the spring solver and the

standard solvers, temporarily duplicate the skeleton and move it

to one side. On the left apply the standard rotate-plane solver and

on the right, create a spring solver.

If you now raise both IK handles you will see a clear difference.

The spring solver has done a better job of distributing the joints.

03

MOrE cOnfigurAtiOn OptiOnS

At this stage you could leave the solver in its default state,

but there are more options available for you to play around and

experiment with. If you select the spring solver’s IK handle and

open the attribute editor you will notice that a series of new

options have now become available under the IK Spring Solver

Attributes tab. The one we are most interested in here is the

Spring Angle Bias.

04

Spring AnglE biAS

By utilising this option, if you click on the large arrow next

to the ramp a larger version will appear, making it even easier

to adjust and tweak to your liking. Editing this will enable you to

alter the angle between the chain’s joints so that you can make

one section appear stiffer than another. Another option to give

the animators yet more freedom to express themselves when

animating longer joint chains.

StEp by StEp UTiliSe MAyA’S SPriNG SOlVer FOr A CHAiN

import maya.mel as mel

mel.eval(“ikSpringSolver”)