MassFX Glossary

Explains some terms used in the MassFX interface.

A mesh that curves or bulges inwards. A golf ball is an example of a concave mesh, as is a torus.

Dynamic and Kinematic rigid bodies must use a convex hull or hulls (see Concave) for the physical shape, while Static rigid bodies can use a concave mesh (see Original) for the simulation. For more information, see Creating a Rigid Body.

An object that joins two rigid bodies, controlling their movement and/or rotation. For more information, see Constraining Physics Objects and MassFX Constraint Helper.
A mesh that never curves or bulges inwards. A sphere and a box are simple examples of convex meshes. Dynamic and Kinematic rigid bodies must use a convex hull or hulls for the physical shape, while Static rigid bodies can use a concave (Original) mesh for the simulation. For more information, see Rigid Body Overview.

By default, MassFX uses a convex physical shape for every rigid body you create because it can be used for every rigid body type and roughly resembles the original graphical mesh.


Dynamic rigid bodies are much like objects in the real world. They fall with gravity, can bump into other objects and can be pushed by them.

The physical shape is moved by the simulation, and the graphical mesh in 3ds Max is updated from that. You cannot use an actual concave physical shape for a Dynamic object, but the Concave physical shape lets you automatically simulate a concave shape with multiple convex physical shapes.

Graphical Mesh

The visual representation of an object in a scene. Compare to physical shape. For more information, see Physical Shapes versus Graphical Shapes.

Initial Transform

The position and orientation of a Dynamic rigid body at the start of the simulation. For more information, see Capture Transform.


Kinematic objects are puppets moved by the strings of your animation. They do not fall with gravity. They can affect the motion of any dynamic objects they encounter but cannot be pushed by other objects.

The graphical mesh for a Kinematic object is controlled by 3ds Max (animated or not), which in turn controls the transform of the physical shape representing the object in the simulation. You cannot use a concave physical shape for a Kinematic object, but the Concave option lets you use multiple physical shapes in the form of a concave mesh.

You can convert a Kinematic object to Dynamic at any point during an animation with the Until Frame settings, available on the Rigid Body Properties rollout and on the Multi-Object Editor panel of the MassFX Tools dialog.

Physical Shape

The non-rendering physical representation of a rigid body or cloth object in a MassFX simulation. The physical shape is often less detailed than its corresponding graphical mesh.

Rigid Body

An object in the physical simulation whose shape and size cannot change. If you make a cylinder in your scene into a rigid body, it can bounce and slide around, but it never bends or snaps, no matter how much force is applied.


A collection of rigid bodies and constraints applied to the bones and joints of a character rig. For more information, see Ragdolls and MassFX Ragdoll.


A state in which a rigid body does not move unless hit by another rigid body that is not sleeping. This helps prevent random slow movement when a body is "settling," or when applied at the start of the simulation, a body can be suspended without being subject to gravity.


The Static rigid body type is similar to the Kinematic type, except that a Static body cannot be animated. A Dynamic rigid body can bump into a Static rigid body and bounce off of it, but the Static rigid body never moves. Static objects are useful both for performance optimization and also because you can use concave meshes for them.