Reactor – Cloth and a Rigid Body

Deformable bodies are more complex than rigid bodies and therefore reactor will take more time to simulate them.

4 types of deformable body
There are four main types of deformable body provided with reactor, each of which is dealt with in their own section:

· Cloth, a deformable 2-dimensional triangular mesh

· Soft Body, a deformable 3-dimensional closed triangular mesh

· Rope, a deformable 1-dimensional chain of vertices.

· Deforming Mesh, a deformable mesh whose vertices have already been animated, for instance the skin on a character rig.

Note – there are 4 methods for deformable constraints:

· Fixing Points in World Space

· Keyframing Points

· Attaching Points to Rigid Bodies

· Attaching Points to Deforming Meshes

=====

We will be using Cloth first.

Setup

My set up is a sphere with some move and rotation animations, with the Skin pose [frame 0] as a cylinder forming sort of a “dress.”

Make a rigid body

First! you need to have a rigid body for the mesh to deform against ... assign rigid body to the sphere:

In order to be able to use our keyframes of the sphere in the simulation, we have to make a particular setting in the Utilities tab; UNYIELDING:

Cloth

My cloth will be this cylinder that will be attached to a sphere:

Add cloth to a cloth collection

Our cloth must be added to a cloth collection:

We will be attaching points [or vertices] to a rigid body [the sphere]

Select the top row of vertices to constrain and Attach to Rigid Body:

There are many settings for the cloth modifier. One you will most likely want is, Avoid Intersections:

When Attach to RigidBody is selected, a new rollout appears so you can pick the sphere:

Deselect sub-object level:

With the sleeve selected, create a Cloth Collection:

Here is a preview:

Remember, we can always go to a certain part of a simulation and make a still frame with the cloth draped naturally as if the sphere was not animated.

To do this, select the rigid body and deselect YIELDING:

This shows a screen shot of how the max file has been changed:

Clear keyframes to go to original state:

If you want to have a frame of a state where the sphere is animated and the cloth is reacting, do this:

Turn back on the UNYIELDING properties of the sphere [so the animation of the sphere is part of the simulation]:

Create animation:

Go to the keyframe you like:

Collapse the reactor cloth into the mesh.

Alt-click the sphere and set as skin pose.

Remove all sphere keyframes [remove the current frame last.]

Alt-click the sphere to assume skin pose if the sphere jumps put out [position.

Now you have a nice editable mesh from the deformed cloth, if you want it for modeling purposes: