In addition to the general preferences, X-Particles has several settings which are used on a project-wide basis.

These can be found in Cinema's Project attributes, which you can see by pressing Ctrl-D (or Cmd-D).

Dynamics tab

X-Particles project settings, Dynamics tab menu.

Subframe Steps

This value affects the Collisions, Fluids and Constraints objects.

Increasing the Subframe Steps value divides each frame time into subframes, reducing the velocity per step that each particle is moved by.

Subframes are also used by most modifiers to reduce the banding effect which is sometimes seen.

If you have fast moving or complex particle motion, increasing the Subframe Steps parameter will increase the accuracy of the Fluids, Constraints and Collisions objects.

It is advised to only increase it by a small amount as it can greatly affect your particle simulation result and drastically slow down the speed of simulation.

XP_PRJ_Substeps 1.1.mp4

Here, we have two animations. In the first one, the Subframe Steps is set at 1.

XP_PRJ_Substeps 10.mp4

This second animation has Subframe Steps increased to 10, reducing the banding, seen in the first video.

If you experience leaks from collisions, especially from rotating/moving objects or when particles are pinched between multiple objects, then increasing Subframe Steps will help the collision engine resolve these cases more accurately.

The second use for this setting is to reduce the banding in the particle stream, caused by some modifiers.

Increasing this value can eliminate banding but will slow down playback, so you should keep this setting as low as possible to avoid too much speed reduction.

You can also increase this value to increase the accuracy/stiffness of dynamics/collisions and constraints.

Collisions