Collision Shapes (or Colliders) are objects that are used for calculating a character’s interaction with other objects in the scene.
This part of the rig is used by the following tools:

• Interacting With Environment
• Ragdoll

By default, Collision Shapes are only visible in the Rig Mode; they are not shown in any of the Edit Modes.
However, you can make them visible by enabling Colliders in the Visible menu:

Creating Collision Shapes

Collision Shapes are created during rigging.
If you are using Quick Rigging Tool, they are added automatically, along with Rigid Bodies.
If you are creating your rig manually, you’ll have to add them yourself.

To create a collider:

1. Select a prototype rig element.

2. Click the Add button in the Collisions section:

To remove a collider:

1. Select it in the Viewport.

2. Click the Remove button in the Collision section:

You don’t need to create a Collision Shape for every part of the rig - only for its biggest parts.

Also, in certain cases, collision shapes in your character’s rig might need some manual adjustments.

If you select a Collision Shape in the Viewport, you can apply Manipulators to it, i.e. move or rotate it.
The Scale manipulator does not work for Collision Shapes, but you can change their dimensions in the dedicated group of settings:

1. Select a Shape

2. Go to the Object Properties panel.

3. Depending on the type of the Shape, you’ll see one of the two setting groups: Box collision or Capsule collision:

Both contain parameters for adjusting the dimensions of the corresponding shapes.
This can be useful when you want Collision Shapes to better match the surface of the character model.

For the same reason, you can add more than one Collision Shape to a rig element.
Some of the default Cascadeur rigs use this, especially for the characters’ feet:

Intersections

When you create Collision Shapes for your rig, you can end up with shapes that intersect with each other:

These intersections can be ignored when it is parent and child colliders that intersect. For example, when an arm collider intersects with a collider for the clavicle, there won’t be any negative effect.

But in other cases - like with the neck and a clavicle on the picture above - such intersections might lead to issues.

If you only plan to use the Interaction with Environment feature, this can be ignored.
But if you enable Ragdoll, you’ll need to adjust the setting so the intersecting shapes would ignore each other.

If you are using the Quick Rigging Tool, this is done automatically.
In other cases, however, you’ll have to set things manually.

To do this:

1. Select the shapes.

2. Go to the Node Editor:

3. You’ll see nodes that represent the Collision Shapes you’ve selected.

4. Select one of these nodes.

5. Open the panel at the left.

6. Find the Collision Material group of settings:

If there is no such group, add it by clicking the plus icon and searching for Collision Material:

7. Now, lock the panel by clicking the lock icon.
This way, it won’t disappear when you deselect the node.

8. Select the node that represents the shape you want to set as ignored.

9. Hold Ctrl and left-click the ignored_objects field.

10. The shape you’d selected should be added to the ignored list:

Now, this Collision Shape won’t register intersections with the shape you’ve added to the field.

Repeat these steps for each shape you want to set as ignored - and for each shape you want to ignore some other shapes.

See Also

Interacting With Environment

Ragdoll

Rig Mode

Quick Rigging Tool

Elements in Rig Mode