I’m wondering how to animate a character grabbing something. Say if my character is grabbing a pole, the pole would be in front of the hand and then the fingers wrap around the pole. How would I do that if the rig is is originally pole->hand, but the fingers go in front of the pole, but it’'s attached to the hand that behind the pole? See my predicament. Is it some weird rig secret or do I do it by hand?
So if i understand correctly, you have the arm rigged so you have a hierarchy of upper arm > lower arm > hand > Pole - as this would be the most common approach. If this is the case there are a couple of choices to make this work, I personally use Option 1, as i get more control on finger movements etc, hope that helps.
Option 1 - Drawing Substitutions. Keep the hand behind the pole and at the point at which you want to wrap fingers round the pole, you do a drawing substitution on the hand to a hand with no fingers, and have a ‘fingers’ only’ layer start which would then be in-front of the pole. This is probably what you we’re going to do anyway ?
Option 2 - Enable 3D on hand layer. This has a potential to throw a few issues up depending on your rig and scene, but can work to good effect. Basically in layer Properties enable 3D and set pivot point to the wrist and then as the hand passes behind the pole, turn the pivot in 3d space so that the upper part of hand will effectively be infant of the pole but other parts will remain behind it. It’s tricky to get right but in some circumstances works ok.
I;ve not come across any clever way using masks or anything to make this any easier, plus i prefer the control when using drawing substitutions.
My absolute favourite way to do this is with a few wee drawing and node changes.
I prefer to work with props outside of the character groups - it makes it easier to work in the scene later on, (once you’ve forgotten what you did to make it work.) You also have the added benefits of being able to composite the scene a little more creatively, and not altering your rig to the point library templates become ineffective.
First, create a new hand drawing. On the colour art layer for the drawing, draw the character’s palm. On the line art layer, draw the fingers and thumb (or whatever you’d like to be visible on top of the pole) - use the cutter tool if you need to manipulate an existing drawing.
Inside your rig group, drag your hand drawing down to the multi port out, creating a second output. Between the hand drawing node and the output node, add a “Line art” node. This creates an output of just the fingers outside of the character.
Outside of the rig use the new multi output to plug into the pole as it’s peg, and either add a cutter to mask the pole with the new fingers, or simply layer them on top of the pole in the main composite.
Should be fairly clear once you get into it, and simple enough for another artist to open up the scene and quickly work out exactly what’s going on
-hope this helps