MassFX Glossary

Concave

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 for the physical mesh, while static rigid bodies may use a concave mesh for the simulation. For more information, see Creating a Rigid Body.

Constraint

An object that joins two rigid bodies, controlling their movement and/or rotation. For more information, see Constraining Physics Objects and MassFX Constraint Helper.

Convex

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 mesh, while static rigid bodies may can a concave mesh for the simulation. For more information, see the section “Adding an object to the simulation”.

Convex Hull

This is the default physical mesh for any rigid body you create, because it can be used for every rigid body type and roughly resembles the original graphical mesh.

Dynamic

Dynamic objects (rigid bodies and skeletons) 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 mesh is moved by the simulation, and the graphical mesh in Max is updated from that. You cannot use a concave physical mesh for a dynamic object, but the Composite Mesh option lets you use multiple physical meshes in the form of a concave mesh.

Graphical Mesh

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

Initial Transform

The position and rotation of a dynamic rigid body (including skeletons) at the start of the simulation. For more information, see Capture Selected.

Kinematic

Kinematic objects (rigid bodies and skeletons) are puppets moved by the strings of your animation. They do not fall with gravity. They push 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 mesh representing the object in the simulation. You cannot use a concave physical mesh for a kinematic object, but the Composite Mesh option lets you use multiple physical meshes 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 Edit panel of the MassFX Tools dialog.

Physical Mesh

The non-rendering physical representation of a rigid body or clothing object in a MassFX simulation. The physical mesh 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.

Skeleton

A collection of rigid bodies and constraints applied to the bones and joints of a character rig. For more information, see Skeletons and Skeleton Helper.

Sleep

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.

Static

Static rigid bodies are similar to kinematic, except that they cannot be animated. Dynamic rigid bodies 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.