Joints Matching

While there are many passes, we recommend running most of them in batches without interventions between them. This large number of passes is there for the exceedingly rare case where corrections need to happen between them, but in reality you are very unlikely to ever encounter those cases.

All of the following requires you are done with Mesh Editing, and were you to make changes to the meshes (creative iteration or other reasons) you’ll likely have to rerun most of this work.

In general when adjusting Volume joints they should be placed so that, in each target transformation, they look best as the masses move across expressions.

Surface joints should be placed so that the delta between the mesh and the Joint is minimized.

We will also offer a map of edits and their sequence, the following is the key to reading the graphs in the following sections:

Volume Joints Adjustments

First run all passes in the following table, in order. This will take care of all volume joints, and none of the surface joints.

After running these passes adjustments to volume joints can then take place.

We recommend operating on LOD4. LOD4 is the resolution that features all, and only, volume joints, making it both a good diagnostic tool as well as the most impacted resolution.

There is no reason to modify any surface joint. Changes (to surface joints) will likely be lost entirely or partially in following passes.

After running these passes, and before the next set, is where the bulk of manual corrections take place (if any are necessary.)

The following sections all warrant inspection, and can sometimes require corrections. The order across the broader categories isn’t strict (eyes, fleshy parts of the mouth, ‘Oh’ shapes etc.).

Eye Direction and Blink

Blinks, Direction, and the combination of the two is always worth inspecting and frequently needs minor fixes to optimize the seal, particularly on protruding or non-human eyes.

The dependencies and order are the obvious ones here. The non combined direction can be worked on separately from the blink, and the combined one is best done by propagating from the blink and then verifying dependencies after.

Jaw Open

Jaw open is a very significant expression, with very high impact on likeness, as well as the node with the most dependencies in the rig.

The most common workflow is to work on jaw_open and propagate to most or all its dependents, and then move downstream to compensate for any over-propagation or issues.

The combination between jaw_open and several mouth shapes is also treated later. How you structure the work of correcting for propagation is up to you, as some measure of personal preference can apply.

Mouth Sides

Mouth interventions can easily be divided into two sections, sided expressions, and central expressions.

It has a very high impact on the likeness of the character, and can require some work. The mouth_cornerPull and mouth_stretch shapes, and their combination, have the most impact. Most of their dependents tend to be fine, or only require minor technical fixes.

It’s worth noting that both stretch and pull are combinations of the left and right side Main Expressions, but this combination is often more present and influential than the split sides are.

The dimple shapes are very similar to the above , except that there’s no combination between it and other merged sided expressions (like there is for stretch and pull combining).

Stretch and Corner pull then might need a technical pass to fix their interactions with jaw open.

The mouth left and right expressions represent a large movement of a fleshy mass, but don’t combine with anything and can be worked on independently of the previous regions.

Mouth Central

The other significant section of the graph involved all the shapes that are central, as well as usually associated with ‘Oh’ shapes. Purse, pucker, and funnel are the key, broadest expressions here, and at least one deep combination (purse, pucker and jaw open) often requires attention.

Lastly, the lips being sucked into the mouth, happening when the jaw is open and the lips are pressed together, needs some attention. Usually this is all that requires work involving the volume joints.

The remainder of the work tends to be technical fixes only.

We suggest the following inspections, while bearing in mind setting to rest, or setting to another expression’s transform, is all that’s needed for the joints in these:

Surface Joints Adjustments

Once All of the volume validation and any necessary corrections have taken place we recommend running passes in the following table:

There are a few notes worth making for these passes.

Eyelids are entirely shared between LOD 0, 1, and 2. Fixing them in LOD 2 should have full effect on all LODs of higher resolution, so we recommend starting with those, and to do so displaying LOD 2.

LOD 1 contains subsets from both LOD 2 and LOD 0. Lips joints are largely but not completely shared across the higher resolution LODs, and are the area worth keeping an eye on the most in this part.

We recommend checking and adjusting the quality of results displaying LOD 2 and 0 independently. Once those have been adjusted, LOD 1 will almost always be fine.

Fixing LOD 1 first might have a knock on effect on the other two (2 and 0) and is therefore not recommended if you care about those. Fixing LOD 1 might be a good idea if you use a combination of LODs that excludes both 2 and 0, though this arguably makes the asset less future proof should you choose to use other LODs between 0 and 3.

LOD3 bears similarities to LOD 1 in that it’s a mix of 2 and 4. It also features far fewer joints than LODs 2 and higher, so we recommend working on LOD 4 (first pass, volume only) and LOD 2, and using LOD 3 only for verification if you use that LOD.

From here and with the above in mind you will mostly be going through subsets of the previous expressions and dependencies.

Eye Direction and Blink

Remember this is for surface joints only.

Mouth Sides

Most notable about the mouth sides is that a large chunk of the graph can be ignored because the combination between pull and stretch rarely needs any attention.

The dimple is still worth inspecting, but less dependent expressions require attention.

And last, the combination of jaw open and pull is also far less work, as its dependents are usually unaffected.

Mouth Central

Central shapes for the mouth remain affected, though fewer are.

Purse, Pucker and Funnel are very similar in “intensity” to their volume passes. If you had to correct there, volume corrections will have affected the surface joints (hierarchically), and these will in turn require some adjustments.

The same is true for the lips being sucked into the mouth.

And for the large left and right shapes.

We commonly don’t see the need for the small technical fixes that closed the previous section.

Tongue Joints Adjustments

The tongue joints are effectively independent of the rest.

The tongue is most affected by the Jaw and teeth work done during the shape modeling (mesh editing) part of the process, but doesn’t inherit any changes from other passes.

Run these passes whenever it’s convenient for your workflow: