Command entry:Particle View
Click Shape Facing in an event or add a Shape Facing operator to the particle system and then select it.
The Shape Facing operator creates each particle as a rectangle that always faces a particular object, camera, or direction. For effects like smoke, fire, water, bubbles, or snowflakes, use Shape Facing with a material containing appropriate opacity and diffuse maps.
By default, the particles' top and bottom sides are parallel to the horizontal plane. The Orientation setting lets you change this default alignment.
Use this control for defining the camera or object toward which the particle will face. This object is known as the Look At object. For the technically minded, the facing is maintained by keeping each particle's local Z axis pointed at the Look At object, or when Use Parallel Direction is on, aligned with the vector between the Particle Source icon and the Look At object.
When off, all particles continuously rotate to stay facing toward the Look At object. Each particle's orientation varies because its location differs from those of the others. When on, all particles face in the same direction, defined by an imaginary line between the Particle Source gizmo center and the Look At object. Default=off.
Use these settings to specify the coordinate system for setting the size, as well as the size parameters. The numeric settings in this group are not animatable.
Sets the facing particles' size as a percentage of the screen width. The actual size of each particle changes as necessary throughout the animation, depending its distance from the camera, to maintain a constant size from the camera's point of view.
This option is available only when the Look At object is a camera, and Use Parallel Direction is off.
Specifies the part of the particle around which rotation is performed when maintaining the facing direction. The choices, available from the drop-down list, are Top, Center, and Bottom. Default=Center.
With Top and Bottom, the center of the corresponding side is used as the particle center for rotation.
This option is useful, for example, when particles are lying on a surface, and each particle is an explosion. In this situation, you'd probably want the entire particle rectangle to appear above the surface, so you'd set Pivot At to Bottom.
Use this drop-down list to choose how particles rotate on the axes not specified by the Look At direction. Default=Align to Horizon.
To spin the particles, choose this option, and in the same event use a Spin operator. In the latter, set Rotation Axis to Particle Space and use the default axis values: X=0, Y=0 , Z=1.