62 - Arm stretch blendShape (Cartoon character rigging series)

We have the stretchy limbs which are fully working but as we stretch them we can see the skin follows along well but it doesn't seem to retain its volume. Its a fundamental thing to retain volume and especially in cartoon stretchy limbs as we want the appearance they as the arm stretches it also becomes thin like stretching a rubber band.

This could be achieved by hooking the scale X and Z of the ribbon joints to the stretchy rig we made so that as the arm length increases, the scale reduces but overall this is quite mechanical.

I prefer to add a blend shape as this gives full control as we can sculpt the amount to stretch we want. So to do this we create a stretch blendShape for each arm and then hook it up to the distance dimension tool that we used to trigger and calculate the stretch rig. This means as the stretch increases, so does the weight of the blendShape.

NOTE: If you can remember while setting up the stretchy limbs we created a global scale multiply/divide node so that the stretchy limbs still work no matter what the scale of the rig. We will see that hooking the blendShapes to the distance dimension tool will work but not while the rig is scaled up or down so in a later tutorial we will bypass this to work at any scale but we will do this when we have both the left and right of the arms and legs so we can tackle them all at the same time to make things easy.

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Please leave any comments or questions below and ill try help as soon as possible.

Thanks for watching :)

Source files can be downloaded at:

https://dl.dropbox.com/u/30666061/JDT...