Animal Rigger ProWeight painting
Find a crease, fix it, and check the fix, with the Weights page tools.
The skin is bound when you build. Each point of the mesh gets a weight for each bone: how much that bone moves it. Most of the time the automatic weights are right. When a pose shows a crease, a dent or skin left behind, fix it here.
The tools themselves are listed on the Weights page. This guide is the order to use them in.
Reading the colours
In Weight Paint mode the mesh shows the picked bone's weights:
- Blue: the bone does not move this point.
- Green and yellow: it moves it partly.
- Red: it moves it fully.
A good weight runs smoothly from red to blue across a joint. A hard line from red to blue makes a crease. A blue patch inside red is a point left behind.
Fix a crease
Find it. On Weights, press Start test poses and scrub the timeline. Stop on the pose where the skin looks wrong.
Pick the bone. Press Paint weights, then click the bone next to the problem, or search for it by name. Names read like Thigh left or Rear toe 1 left.
Try a quick fix first. Select the bad points in Edit Mode, or leave nothing selected to work on the whole bone, and press Smooth. Smoothing fixes most creases.
Paint what is left. Blur softens a hard edge. Add and Subtract push the weight up or down a little at a time. Paint sets it to the brush weight.
Check other poses. Scrub through all the test poses. A fix for one pose can spoil another.
Copy it across. Press Copy to other side, so the other side matches without painting it again.
Press Stop test poses, then Done painting.
Twist bones
With Twist on under Rig features, the upper legs are split into parts along their length, so a twist spreads out instead of pinching at one joint. The skin of the leg is then carried by the parts, Thigh twist 0 left to Thigh twist 2 left, and the bone called Thigh left may show all blue. Pick the twist parts to paint the leg.
With Joint helpers on, bones such as Thigh corrective left keep the hip and shoulder in shape when they bend. Leave them to the automatic weights unless a joint collapses.
Exact numbers
To set an exact weight on a few points, such as the tip of an ear:
- Turn on Only selected.
- In Weight Paint, press B and drag a box round the points.
- Press Give all (1), Set (the brush weight) or Take away (0).
The other bones share what is left in the shares they had, so each point still adds up to one.
When to start again
- Auto weights puts the automatic weights back on the selected points, or on the picked bone's skin.
- Bind skin again on Generate redoes all the automatic weights, and keeps what you painted by hand.
- Robust bind on Generate is a slower method for legs that touch, parts that overlap, or a mesh with holes.
Before you export
Press Find problems. It selects any points that no bone moves, that do not add up to one, that have more than eight bones, or that are moved by a bone on the wrong side or far away. Fix those first: a game engine shows them all.