The Position Raycast operator allows you to cast rays towards the surface of an object, and place particles where the rays hit.
Particle Position: rays will be cast from the particle’s current position.
Project from Icon: rays will be cast from the particle’s current position, projected onto the plane of the applicable tyIcon.
Random on Icon: rays will be cast from a random location on the enclosed plane of the applicable tyIcon.
Value: the amount to interpolate particle positionx from their previous value to the new value.
Keep original: particle orientations will not be changed.
Surface: particles will be aligned to the surface their ray hit.
The Position Raycast operator offers no extra controls over surface alignment. A Rotation operator should be used instead if more control over surface alignment is required.