Rendering particles

There are two ways of rendering particles in mantra: rendering a particle system and rendering geometry as points. To render particle systems you must create particle geometry in POPs, while you can render points from any geometry object.

Rendering particle systems

Particle primitives created in a particle system using a POP network SOP can be rendered directly in mantra. By default, particle system primitives are rendered as spheres.

You can change the shape by appending any of the following:

Render POP	Allows you to change the Particle Type to render as spheres, disks, lines, tubes, capped tubes, or rounded tubes.
Instance POP	Allows you to render particles as instanced geometry.
Sprite POP	Allows you to render textures on particles.

Note

You must re-simulate the POP network for any changes to take effect.

Rendering geometry as points

In mantra, you can efficiently render the points in a model directly using point primitives without having to create a particle system. Point rendering will render the points in a model as disks, oriented toward the camera with only a single shader evaluation per point.

On a geometry object, click the Geometry sub-tab of the Render tab.
Turn on the Render As Points checkbox.
Render using a mantra output driver.

Rendering attributes for points and particles

The following attributes can be used in SOPs to adjust rendering of particles or points.

`pscale`	Can be used to change the size of the particles for rendering. The parameter will be multiplied by the original particle size from POPs. You can add this attribute at the vertex, point, primitive, and detail levels.
`width`	Can be used to change the size of the particles for rendering. The parameter will be multiplied by the original particle size from POPs. You can add this attribute at the vertex, point, primitive, and detail levels.
`orient`	The orient attribute controls how disks are oriented for point rendering. Orientation is specified as a normal vector. You can add this attribute at the vertex and point levels.
`v`	The velocity point attribute controls the length of lines or tubes for particle rendering.