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Synopsis

collision [-friction float] [-name string] [-resilience float] [objects]

collision is undoable, queryable, and editable.

The collision command causes particles to collide with geometry. It also allows you to specify values for the surface properties (friction and resilience) of the collision. These values are stored in the geoConnector node for the geometry object. Unlike earlier versions of Maya, there is no separate "collision node." If a soft object is in the selection list, the collision command assumes that you want to make it a collider. In order to make the soft object collide with something use, use connectDynamic -c. The collision menu option sorts this out using the lead object rule and issues the necessary commands. On creation, this command returns a string array of the geometry names that were setup for particle collision.When the command is used to query information, there are several possible return types. These include:

Return value

string[] Geometry names that were setup for particle collision.

In query mode, return type is based on queried flag.

Related

event, particle

Flags

friction, name, resilience
Long name (short name) Argument types Properties
-name(-n) string
This flag is obsolete. In maya 2.0, there is no longer a separate "collision node," thus there is nothing to name. See the collision documentation. This flag is included only to allow scripts written with older versions of Maya to run. It will give you a warning message but will not do anything.
-resilience(-r) float queryedit
Resilience of the surface. This is the amount of the colliding particle's velocity reflected along the normal of the surface. A value of 1 will give perfect reflection, while a value of 0 will have no reflection along the normal of the surface.
-friction(-f) float queryedit
Friction of the surface. This is the amount of the colliding particle's velocity parallel to the surface which is removed when the particle collides. A value of 0 will mean that no tangential velocity is lost, while a value of 1 will cause the particle to reflect straight along the normal of the surface.

Flag can appear in Create mode of command Flag can appear in Edit mode of command
Flag can appear in Query mode of command Flag can be used more than once in a command.

MEL examples

collision -r .75 -f .1  nurbsSphere1 particle1;
// Causes particles of particle1 to collide with nurbsSphere1,
// and sets a resilience value of 0.75 and a friction value of 0.1
// for the surface.

collision -q -f nurbsSphere1;
// Returns the friction value stored in the geoConnector for nurbsSphere1.

collision -q -f nurbsSphere1 particleShape1;
// Returns the friction value that particleShape1 is using for collisions
// against nurbsSphere1.  This may be the same as the friction stored in
// nurbsSphere1's geoConnector.  Or, if the user broke that connection,
// then it is whatever value is in the particleShape1's collisionFriction
// attribute that is used for collision with nurbsSphere1.

collision -q nurbsSphere1 particleShape1;
// Returns whether or not particleShape1 is checking for collisions
// against nurbsSphere1.

collision -q particleShape1;
// Returns all of the geometries that particleShape1 is colliding with.