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Deformable Bodies

You can use rigid bodies in reactor to model any real-world object whose shape doesn't change over time. However, what if you want to simulate an object whose geometry does change over the course of the simulation, such as a cloak, hair, foam bricks, or perhaps a slithering tentacle? reactor allows you to model these with a second category of objects, called deformable bodies. The geometry (vertices) of deformable bodies can change over time, driven either by reactor during the simulation or by existing animation in 3ds Max Design, allowing the objects to bend, flex, and stretch while affecting and being affected by the rest of objects in the world simulation.

ImportantThe Havok 3 engine does not support deformable bodies in reactor; you can use these only with the Havok 1 engine.

In addition to creating entirely deformable objects, you can combine deformable bodies with rigid bodies, for instance to add secondary motion to a simulated character. Secondary motion could include swirling clothing, wobbling flesh, or a swinging tail. Deformable objects are also useful for environmental effects such as swinging ropes and chains, curtains, and flags with dynamic wind.

Generally, you create a deformable body in reactor by first creating a mesh or spline that models the object's basic shape, and then applying a special modifier. You can then specify additional physical properties for the object. reactor includes four main types of deformable bodies, each of which is dealt with in its own section:

As with rigid bodies, you must add deformable bodies to a collection in order to be added to the simulation. Each deformable body type has its own corresponding collection type.

Also like rigid bodies, you can constrain the possible movement of deformable bodies: see Constraining Deformable Bodies.

NoteDeformable bodies are more complex than rigid bodies, so reactor requires more time to simulate them.

Working with Deformable-Body Vertices

reactor includes several tools for working with individual vertices in deformable bodies. The topics covering these are: