Deflectors are a hugely powerful part of the particle simulator. With deflectors you can have particles impact on shapes and surfaces and even simulate particles colliding with objects in a live action shot.
A particle simulation can include multiple deflectors, allowing for very complex setups.
Deflectors can be added from the timeline or from the Controls panel using the icon to the right of the Deflectors group.
The Bounce and Friction settings in the Particle system -> Movement properties directly affect how particles interact with deflectors.
|•||Active - turns the deflector on and off.|
|•||Front face - whether a particle can collide with the front face of a deflector.|
|•||Back face - whether a particle can collide with the back face of a deflector.|
|•||Kill particles - kills particles when they come into contact with the deflector.|
|•||Kill mobile emitters - kill mobile emitters when they come into contact with the deflector.|
Deflectors can be cuboid shapes generated inside the simulator or you can use another layer on the current timeline. Therefore if you've already got a plane set up as your 'floor', you can use that same layer as a particle deflector.
The cuboid properties enable you to change the shape of the cube and transform it in 3D space.
The Mask option also uses the Deflector as a 3D mask for the particles. Any particles that are behind or inside the deflector from the point of view of the camera will not be visible.
When using a layer as a deflector you need to select the source layer from the deflector's properties.
The infinite plane option extends the deflector along the axis of the plane in all directions. This can be considerably easier than having to enlarge the layer itself to cover the entire 3D scene.
If particles are passing through your deflector layer, check the Front face and Back face properties as described above.