# Rotation¶

Reference

Panel: Particle System ‣ Rotation

These parameters specify how the individual particles are rotated during their travel. To visualize the rotation of a particle you should choose visualization type Axis in the Visualization panel and increase the Display Size.

Orientation Axis

Sets the initial rotation of the particle by aligning the X axis in the direction of:

None
The global X axis.
Normal
Orient to the emitter’s surface normal, the objects Y axis points outwards.
Normal-Tangent
As with normal, orient the Y axis to the surface normal. Also orient the X axis to the tangent for control over the objects rotation about the normal. requires UV coordinates, the UV rotation effects the objects orientation, currently uses the active UV map. This allow deformation without the objects rotating in relation to their surface.
Velocity
The particle’s initial velocity.
Global X, Y, Z
One of the global axes.
Object X, Y, Z
One of the emitter object axes.
Random
Randomizes rotation.
Phase
Initial rotation phase.
Randomize Phase
Adds a random variation to the Phase.
Dynamic
If Dynamic is enabled, only initializes particles to the choosen rotation and angular velocity and let the physics simulation handle the rest. Particles then change their angular velocity if they collide with other objects (like in the real world due to friction between the colliding surfaces). Otherwise the angular velocity is predetermined at all times (i.e. set rotation to dynamic/constant).

## Angular Velocity¶

Reference

Panel: Particle System ‣ Rotation ‣ Angular Velocity
Axis

The selector specifies the axis of angular velocity to be.

None
A zero vector (no rotation).
Spin
The particles velocity vector.
Random
A random vector.

Hint

Curve Guide

If you use a Curve Guide and want the particles to follow the curve, you have to set Angular Velocity to Spin and leave the rotation on Constant (i.e. do not turn on Dynamic). Curve Follow does not work for particles.

Amount
The magnitude of angular velocity.