Creating Tendons

Like tendons in an actual body, tendons in Physique link one bone to another. They spread the effect of moving one link to the skin around a different link. Tendons can improve the realism of skin movement when it is animated by Physique.

Basically, a tendon consists of base points that live on a cross section near the skin. A base point is attached to another link on the skeleton that pulls it. As the tendon base point is pulled, it deforms the skin around it. Several parameters control how much the point is pulled in each direction.

You insert the tendon cross section at the location where you want the skin to stretch. You then attach it to the link that influences the movement.

Each link can contain several tendon cross sections, and each control point may be attached to a separate link. In a practical application, however, such as in the area below the armpits, you might have two control points attached to each of the left and right clavicles.

Procedures

To create and attach a tendon:

Go to the Tendons sub-object level. In the Tendons rollout Selection Level group, activate (Link).
In a viewport, select a link.
In the Insert Settings group, click to turn on Insert.
In a viewport, position the cursor over the link.
The cursor changes to a small star.
Click to create cross sections on the link.
Click to turn off Insert.
TipYou can also right-click in a viewport to turn off tendon creation.
In the Selection Level group, turn on (Cross Section).
Use the Rotate tool to rotate the cross section so the control points are positioned in useful places.
In the Tendon Parameters group, use the Radius spinner to scale the cross section radially so the control points fall close to the surface of the skin.
In the Selection Level group, activate (Control Point), then in a viewport, select one or more control points.
In the Edit Commands group, turn on Attach, then in a viewport, click a different link.
Tendons span the area between the links.
Adjust the Pinch, Pull, and Stretch settings to adjust the skin behavior.
Adjust the Upper and Lower Boundary settings to control the extent of the effect on neighboring links.

To attach a tendon to another link:

In the Tendons rollout Selection Level group, activate (Control Point) to make it the active selection level.
In a viewport, select one or more of the tendon's attach points.
Click a point to select it; use Ctrl+click to add points to the selection; or drag a rectangular region to select multiple points.
In the Edit Commands group, turn on Attach.
In a viewport, click the link to which you want to attach the tendon.
In the viewports, red lines appear showing the tendon's connection from its base to the other link. The skin mesh might also deform as a result of attaching the tendon.

TipThe tendon can have fixed attach points that are not connected to another link. These are useful for giving some rigidity to the skin, as when (in an actual body) a bone lies close to the skin's surface. For example, you might leave two fixed attach points on either side of a character's chest area, to simulate the effect of the sternum. When all tendons are attached to other links, the skin over the base link can have a "squishy" appearance when it is animated. This is appropriate for some animated characters, but not for others.

To delete a tendon:

At the Tendons sub-object (Link) selection level, select the link that has the tendon you want to remove.
In the Insert Settings group, click Delete.