Distributions
Uniform distributions are the simplest to understand: every point in the specified shape (a cuboid, or ellipsoid, or sphere hull) is equally likely to be chosen for the property.
Distributions can be changed by right-clicking on the respective property of the Particle System in the Property Inspector (click on the name, e.g. "velocity").
The following uniform distributions are available:
Cuboid, Plane & Line
Cuboids are the base for planes and lines. Just scale one or two axes (respectively) to zero.
Sphere Hulls
Spheres can be transformed into circles by scaling one axis to zero.
Sphere Volume
Sphere volumes can be transformed into circles as well.
Spheres and Cuboids can be rotated as well.
Gaussian Distribution
There is also the Gaussian Distribution, which has a smooth falloff to all sides and looks more natural.
Constant Value ("Distribution")
If all values should be the same, you either can set the size to zero, or use a Constant Distribution.
The origin, size and rotations of the distributions can be animated using the Graph Editor. Switching between different shapes is currently not possible on the timeline, so a property can have only one type.
To create these images, I set the initial velocity to zero, and applied the distribution to the initial position.
Created: 08:17, 04. Jan 2021; Most recent change: 17:57, 16. Sep 2023