gravity

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Synopsis

gravity [-attenuation float] [-directionX float] [-directionY float] [-directionZ float] [-magnitude float] [-maxDistance linear] [-name string] [-perVertex boolean] [-position linear linear linear] [-torusSectionRadius linear] [-volumeExclusion boolean] [-volumeOffset linear linear linear] [-volumeShape string] [-volumeSweep angle] [objects]

gravity is undoable, queryable, and editable.

If fields are created, this command returns the names of each owning shape and of the field shapes themselves. If a field was queried, the results of the query are returned. If a field was edited, the field name is returned.

If no object names are provided but the active selection list is non-empty, the command creates a field for every object in the list. If the list is empty, the command defaults to -pos 0 0 0. A gravity field simulates the Earth's gravitational force. It pulls objects in a fixed direction (generally downward) entirely independent of their position or mass.

The transform is the associated dependency node. Use connectDynamic to cause the field to affect a dynamic object.

If fields are created, this command returns the names of each of the fields. If a field was queried, the results of the query are returned. If a field was edited, the field name is returned.

If object names are provided or the active selection list is non-empty, the command creates a field for every object in the list and calls addDynamic to add it to the object. If the list is empty, the command defaults to -pos 0 0 0.

Setting the -pos flag with objects named on the command line is an error.

The default for -dx -dy -dz is always the opposite of the current up direction. For example, if the current up direction is (0,1,0) (a standard Maya configuration), then the gravity default is -dx 0 -dy -1 -dz 0. The default for -a is 9.8. 9.8 meters per second squared happens to be standard Earth gravity, but in fact Maya interprets this value as centimeters per second squared. If we were to use it as meters per second squared then with default Maya units, your particles would vanish almost in the wink of an eye. If you want a different value, set it in the gravity option box.

Return value

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

Related

Flags

Long name (short name)	Argument types	Properties
-attenuation(-att)	float
Attentuation rate of field
-directionX(-dx)	float
X-component of direction.
-directionY(-dy)	float
Y-component of direction.
-directionZ(-dz)	float
Z-component of direction
-magnitude(-m)	float
Strength of field.
-maxDistance(-mxd)	linear
Maximum distance at which field is exerted. -1 indicates that the field has no maximum distance.
-name(-n)	string
name of field
-perVertex(-pv)	boolean
Per-vertex application. If this flag is set true, then each individual point (CV, particle, vertex,etc.) of the chosen object exerts an identical copy of the force field. If this flag is set to false, then the froce is exerted only from the geometric center of the set of points.
-position(-pos)	linear linear linear
Position in space (x,y,z) where you want to place a gravity field. The gravity then emanates from this position in space rather than from an object. Note that you can both use -pos (creating a field at a position) and also provide object names.
-torusSectionRadius(-tsr)	linear
Section radius for a torus volume. Applies only to torus. Similar to the section radius in the torus modelling primitive.
-volumeExclusion(-vex)	boolean
Volume exclusion of the field. If true, points outside the volume (defined by the volume shape attribute) are affected, If false, points inside the volume are affected. Has no effect if volumeShape is set to "none."
-volumeOffset(-vof)	linear linear linear
Volume offset of the field. Volume offset translates the field's volume by the specified amount from the actual field location. This is in the field's local space.
-volumeShape(-vsh)	string
Volume shape of the field. Sets/edits/queries the field's volume shape attribute. If set to any value other than "none", determines a 3-D volume within which the field has effect. Values are: "none," "cube," "sphere," "cylinder," "cone," "torus."
-volumeSweep(-vsw)	angle
Volume sweep of the field. Applies only to sphere, cone, cylinder, and torus. Similar effect to the sweep attribute in modelling.

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

  gravity particle1;
// Creates a gravity field and adds it to the list of fields
// owned by particle1.

  gravity -pos -2 0 4;
// Creates a gravity field at position (0,2,4) in world coordinates.

  gravity -e -att 10.4 MyGravity;
// Changes the gravitational acceleration of the field called
// "MyGravity" to 10.4.

  gravity -dx 0 -dy 1.0 -dz 0.5;
// Creates a gravity field pulling in direction (0,1,0.5) for every
// active selection. If there is no active selection, it creates this
// field at world position (0,0,0).