7.2.135 ui-motion

(ui-motion {inertia|constrain|own-coordinates} {on|off})

Enable or disable certain properties of mouse-controlled motion. The purpose of this command is to give access to the respective toggles of the Main panel's Motion menu through GCL commands. See Mouse Motions.

inertia

Normally, moving objects have inertia: if the mouse is still moving when the button is released, the selected object continues to move. When inertia is off, objects cease to move as soon as you release the mouse.

constrain

It's sometimes handy to move an object in a direction aligned with a coordinate axis: exactly horizontally or vertically. Calling (ui-motion constrain on) changes the interpretation of mouse motions to allow this; approximately-horizontal or approximately-vertical mouse dragging becomes exactly horizontal or vertical motion. Note that the motion is still along the X or Y axes of the camera in which you move the mouse, not necessarily the object's own coordinate system.

own-coordinates

It's sometimes handy to move objects with respect to the coordinate system where they were defined, rather than with respect to some camera's view. When (ui-motion own-coordinates on) has been called, all motions are interpreted that way: dragging the mouse rightward in translate mode moves the object in its own +X direction, and so on. May be especially useful in conjunction with the (ui-motion constrain on) command.