Reflections

In the real world all objects exhibit some degree of reflectivity based on surface shine, brightness, angle of view, and proximity to reflected objects. Motion simulates this natural effect, equipping every object with a set of parameters to create and control realistic-looking reflections. When Reflections are enabled for an object, all other objects in the scene are reflected but may only be visible from specific angles and distances.

Figure. Canvas showing an object reflecting other objects.

Reflection Parameters

The Properties Inspector includes a Reflection section.

Reflections Parameters in the Properties Inspector:

Reflection: This checkbox enables reflections based on the settings of the parameters in the group. (When selected, the checkbox turns blue.)
Reflectivity: This slider controls how shiny the object’s surface appears. 0% indicates no reflectivity, while 100% is perfectly reflective, like a mirror.
Blur Amount: This slider controls whether real reflections appear in sharp focus or quite blurry, depending on the surface quality of the reflecting object.
Falloff: This checkbox determines whether the reflection fades with distance from the object, producing a more realistic result. There are additional options in the Falloff section when this checkbox is enabled:
Begin Distance: This slider determines the distance (inside the reflection) where the falloff begins. When the slider is set to 0, falloff starts at the reflection plane.
End Distance: This slider determines the distance where the falloff ends, beyond which the reflection isn’t visible. Adjusting this slider moves the falloff point closer to the reflection plane, which causes less of the reflected image to appear.
Exponent: This slider controls how quickly a reflection gets fainter as the reflected object gets farther from the reflective surface.
Blend Mode: This pop-up menu determines the blend mode used for the reflection. Blend modes other than “add” are useful for achieving different looks, even if they aren’t physically intuitive. For more about blend modes, see Blend Modes.

Other Reflection Parameters

Casts Reflection: The Properties Inspector of every object also contains a Casts Reflections pop-up menu (in the Blending section) that controls whether an object is reflective. There are three options:
- Yes: The object is reflected in nearby reflective objects.
- No: The object is ignored by reflective surfaces.
- Reflection Only: The object becomes invisible, but appears in reflective surfaces around it.

Reflections and Groups

In addition to choosing reflections settings for individual objects, you can adjust settings for an entire group. Reflections settings for a group override the settings of individual layers in the group. For example, if an object in a group is not set to receive reflections, turning that setting on for the whole group forces the individual object to receive them. Turning off the setting for the group allows the objects’ settings to act as expected.

Cast Reflections settings work differently. If the group is set to cast reflections, individual objects’ reflections can still be turned off (or set to Reflections Only). However, if the group is set to not cast reflections at all, individual objects never cast a reflection, regardless of their setting.

Disabling Reflections

Rendering reflections can significantly impact playback performance, so you might want to temporarily disable reflections to improve playback speed while working on other aspects of your project.

To disable rendering of reflections

From the Render pop-up menu in the status bar, choose Reflections (or press Option-Control-R).

Limiting Recursive Reflections

When a reflective object is reflected in another object, the first object can be seen in the reflection, potentially causing an endless repetition of reflections. Motion limits the number of reflective bounces that can occur in a scene, preserving performance and preventing the viewer from getting lost in infinity. The number of allowed reflections is set per project.

Figure. Canvas showing recursive reflections.

To set the number of recursive reflections in the current project

Choose Edit > Project Properties (or press Command-J).
The Properties Inspector for the project opens.
In the Reflections section, adjust the Maximum Bounces slider.