Soft Constraints

Although Constraint tags work for rigid bodies only, the following workaround will enable you to constrain the motion of soft bodies. Suppose you have placed a cloth in a gravity field. The cloth should adopt the shape indicated below (right cloth).

Example:

Left: the starting shape of the cloth. Right: the shape the cloth should adopt.

To make the cloth adopt the required shape:

Create a non-dynamic copy of the soft body, in other words a copy without dynamics tags.

Animate the copy using keyframes.

Here, the position of the copy has been animated.

In the Soft Body dialog of the soft body, under Target, type in the name of the copy. All soft body points of zero mass will now follow the copy.

The next stage is to assign a vertex map and Restriction tag to the copy. So select the relevant points and weight them appropriately using the Set Vertex Weight command (main menu: Selection > Set Vertex Weight from the main menu). Next, give a name to the vertex map.

If you now create a Restriction tag (Object Manager: Tags > CINEMA 4D Tags > Restriction from the Object manager, you will be able to adjust the strength of up to six vertex maps. The strength controls how closely the soft body points will follow the copy.

The checkered cloth is the soft body, the grey rectangle just to its right is the copy. Two vertex maps have been created: Row1 (Strength = 30%) and Row2 (Strength = 10%). The two point rows are following the copy with varying strength.