We will ensure when the elbows or knees are fully straight, that they look correct, and also that when they are fully bent, they look great as well. We will achieve this with a simple double-joint and, in the elbow, a simple set of bones for the biceps and forearm. In the knee area, there is a more complex set of drivers and constraints that make the large mass of the thighs, calves, and knees move properly for a full range of motion.
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Images on This Page
All the images on this page are of Princess Verachantesse, whose elbow and knee rig we will re-create onto Monette Taida.
You can see from these images that there are two red bones on the inside of her elbow, and a complex set of bones around her knees, mostly also in red.
These are our target bones! Let’s do this!
- (8m13s) Free Technical Overview: ELBOWS Relationships and Constraints also available on Youtube.
- (14m55s) Free Technical Overview: KNEES Relationships and Constraints also available on Youtube.
- (43m45s) Elbows. Two driven and constrained bones on the inside of the elbow. The bicep stretches to the foream and modifies its volume with drivers. The forearm corrective stretches to the humerus and modifies its volume with drivers as well. This session runs long because I decide part-way through that Monette Taida’s arm is different enough from Verachantesse’s that I need a slightly different setup.
- (4m09s) Elbows Addendum. The mystery of the weird bicep corrective at extreme poses, and how to solve it. We add a bone on the humerus that copies its rotation at a slight amount, and the bicep corrective becomes its child.
- (33m48s) Thighs. Thigh squish, and its 3 children.
- (11m52s) Calves. Squishing to match the thighs. At the end we also do a minor constraint to make the thighs look better.
- (18m14s) Patella for the front of the knee. And also some minor fixes to the upper thighs considering the new rig’s differing deforms.
Here is the Hierarchy of the Elbows and Knees rigs:
Here are the driver values:
- Z Scale == 1.1 - (elbow * .14)
- X Scale == 0.5 + (elbow * .4)
- Z Scale == 1.12 - (elbow * .12)
- Y Location == max(0,knee - 2.1) * .005
- Z Location == -1 * max(0,knee - 2.25) * .055
- X Scale == 1 + max(0,knee - 1.6) * .25
- Head/Tail Stretch To Constraint == max(0, min(1, (3 - knee) * .5))
- def-thighSquishOuter/Inner.L/R (two bones)
- Y Scale == 1 - max(0,knee - 1.6) * .35
- Y Location == max(0,knee - 2) * .07
- Z Location == max(0,knee - 2) * -.05
- X Scale == 1 + max(0,knee - 1.8) * .1
- Z Location == (knee - .4) * .012 (Z should point 45 degrees back/up)
We have three offerings. Two ~12-minute free technical overview videos. This includes all the bones, their relationships, constraints, and some discussion on Princess Verachantesse. Finally, a long-form lesson where we place all the bones from scratch on Monette Taida.
- FREE technical overview videos, Elbows: Published March 12th, 2022 also available on Youtube.
- FREE technical overview videos, Knees: Published March 12th, 2022 also available on Youtube.
- Paid step-by-step setup: On FlippedNormals store or on Gumroad.
The free technical overviews use Princess Verachantesse as the subject, but the full tutorial is done with Monette Taida, to match the other tutorial sessions done so far.