Name

The shader’s name. Enter any name you like, or leave the default.

Maximum Tree Depth

Maximum number of branches down the tree until it stops splitting into further branches. Range is 1 to 50.

Maximum Leaf Size

Maximum number of particles each leaf on the tree can hold before converting that leaf into a branch to allow for further splitting. Range is 1 to 30.

Maximum Number of Trees

When using motion blur, instead of generating one tree for the whole traversal of particles through time, the open/close shutter time interval is split into a maximum of this number and that many trees generated for each time slice. This speeds up rendering, and may even increase memory for fast moving particles. Your mileage may vary. Range is 1 to 20.