Rigging the Hand with Set Driven Keys

Day 04

VFX JOURNAL- LEARNING HOW TO RIG

9/6/20243 min read

I rigged Julie's hand using set-driven keys. This simplifies the process of moving the fingers when they bend in. Thanks to this, each finger can be bent by typing in or dragging the value between 0 and 1 instead of controlling and bending each limb.

I followed Academy Phoenix's YouTube tutorial for this rig as well.

I am breaking down the process into two parts, especially to explain my troubleshooting process to adjust the angle of the joints.

1. Setting the set-driven keys

2. Troubleshooting

1. Setting the set-driven keys

- While selecting the wrist controller, go to the Channel Box, then press 'Edit' -> 'Add Attribute'.

- This is where you can add attributes to a component. Type in a name on 'Long Name', then press 'enter' for the option box to automatically create a 'Nice name'. Make sure the data type is set to 'Float' and the attribute type to 'Scalar'. Add minimum and maximum values, then press 'Add' to add the attribute. I did this for all five fingers, naming them '(finger name) Control'.

- After changing the mode to 'Animation', go to 'Key' -> 'Set Driven Key' -> 'Set'.

- Select the wrist controller and press 'Load Driver'. This will show the attributes added to the wrist controller. Select the attribute you desire to make a change.

ex) If you want to curl the pinky finger, select the 'Pinky Control', which is the attribute that you made earlier.

- Select the joints you want to influence, then press 'Load Driven'. Then select the attributes of the joints that you want to key. For me, I selected 'Rotate Y' to curl my fingers.

- While making sure the value of the attribute is set to '0(or any minimum value)', press 'Key'. Curl the joints selected, change the value of the attribute to '1(or any maximum value)', then press 'Key' again. This is 'keying' the rotation value of the joints via the attribute value.

- Repeat this for the rest of the fingers, including the ones on the other side.

2. Troubleshooting

When I was trying to curl the fingers to key them, I noticed that some of the fingers were not curling in the way that I wanted them to be. For example, this joint was curling in the opposite direction than the other ones.

I knew that this was an issue caused by the rotation pivot being skewed, so I tried rotating the joint and setting it as a preferred angle. However, this caused the other joints to be influenced, which led me to have to manually tweak them again.

Instead, I pressed 'D' on my keyboard to change the rotation pivot without influencing any other joints. This helped me keep the original location of all the joints, but adjust the rotation axis the way that I wanted.

After this process, I clicked 'Set Preferred Angle' under 'Skeleton', then 'Freeze Transformation'.