Shadows

Motion scenes that include Point or Spot lights can recreate more natural, realistic effects by casting shadows. Shadows are created when opaque or semi-opaque object blocks light from hitting another object. In order to see a shadow in Motion, you need at least three things: A shadow-casting light source, an object to cast a shadow, and another object upon which the shadow is cast. Multiple lights will cast multiple shadows that may or may not be visible depending on the relative positions and settings of the objects in the scene.

Note: Ambient and Directional lights do not cast shadows.

Warning: Some changes you make to 3D objects with shadows applied may cause the shadows to disappear. This occurs when the change causes rasterization of the 3D object—adjusting the opacity of a group or turning on the glow attributes for a text object, for example. Flattening the 3D group will allow it to cast shadows again. For more information about disappearing shadows, see Shadows and Rasterization.

In Motion, you can control whether a light source will create shadows, and whether each object in the scene receives shadows and/or casts shadows. You can even have an object cast a shadow when it is itself invisible. The strength, sharpness, shape, and position of the shadow depends on the type and positions of the lights and relative position of all three objects.

Cast Shadows Versus Drop Shadows

There are two common types of shadow effects used in motion graphics work: drop shadows and cast shadows. Motion can create both effects, but because they have different purposes and applications, it may be helpful to consider the differences between them. Both cast and drop shadows simulate the effect of light being blocked by an opaque object. But a cast shadow is a 3D effect requiring a light source and an object for the shadow to fall upon, and a drop shadow is a 2D effect simulating a cast shadow without a light source and so is limited to a very small range of settings.

Figure. Canvas showing examples of a drop shadow and a cast shadow.

Drop shadows are commonly used to simulate depth and separate foreground objects from the background in 2D projects. The classic drop shadow effect is used on light-colored titles so the text is legible against both dark and light backgrounds. In a drop shadow effect, the imaginary light source does not create any shading effect on the surface of the object and the shadow’s position is set at a fixed direction.

The shadow is actually rendered as a part of the foreground object, so it doesn’t interact with any background objects. However, because it is an effect, a drop shadow’s appearance can be directly customized; the softness, opacity, position, and even its color can be customized and animated without the need to indirectly manipulate a light source.

Cast shadows are true 3D effects, and their appearance is determined only by the light source and the other objects in the scene. Multiple cast shadows interact with each other and take their shapes based on the surfaces and positions of the objects upon which they are cast.

Shadow Controls

Shadows are controlled by adjusting settings in two places. Point and spot lights have a Shadows section in the Light tab of the Inspector, and all visible objects have a Shadows section in the Properties tab in the Inspector.

Note: 2D groups at the root level of the project do not have lighting or shadow controls. To enable shadows on such a group, convert it to 3D or embed it within another 3D group.

Shadow Parameters in the Light Tab
  • Shadows Checkbox: The shadows group in the Light tab of the Inspector can be turned on and off using the Shadows checkbox. By default, it is deselected. This allows you to set certain lights to cast shadows, and others not to cast shadows.

    Selecting this checkbox causes the light to cast shadows on objects in front of it if they also have their shadow controls enabled. Deselecting it will exempt the light from generating any shadows, regardless of the settings on the individual objects.

  • Opacity: This slider controls the apparent opacity of the shadow. Dragging the slider to the left creates a lighter shadow.
    Figure. Canvas showing object with shadow opacity set to 75% and set to 25%.
  • Softness: This slider determines how blurry a shadow will appear.

    Note: The appearance of a shadow is dependent on the rendering quality of the object casting it. Because a shadow may be larger than the original object, you may see some jagged edges or aliasing on a shadow that was not visible on the source object. If you see such artifacts, be sure to check how your image looks when the project is set to best quality, rather than draft or normal. For more about Canvas display quality, see Canvas View Options.

  • Uniform Softness: Select this checkbox to constrain the results of the softness slider to a uniform amount of blur on the shadow regardless of distance between the light, the object casting the shadow, and the object receiving the shadow.

    By deselecting the checkbox, you enable nonuniform softness, where the farther away the objects are from each other, the more blur is applied.

    Note: Selecting non-uniform softness can impact playback performance.

    Figure. Canvas showing object with shadow uniform softness setting on and off.

    Note: Intersecting objects reveal an unnatural effect of using uniform softness. Because an equal amount of blur is applied to the entire shadow, the blur appears to spill out in front of the intersecting object, creating a strange appearance. This effect can be eliminated in two ways; either by deselecting the Uniform Softness checkbox or setting the object to not receive shadows.

    Figure. Canvas showing intersecting objects with the uniform softness setting turned on and off.
  • Color: This control allows you to set the color of the shadow. While semi-transparent objects will cast lighter shadows than opaque objects, you cannot create light transmission effects wherein a semi-transparent object allows some light to pass through it, picking up it’s color or pattern and projecting that as part of the shadow as light passing through stained glass would. For more on using the color controls, see Color Controls.

    Note: When light shading is turned on, shadows are multiplied with the objects upon which they are cast. This means that the result will be a darkening effect, regardless of the color of the shadow. If you select a shadow color lighter than the background upon which is is cast, the shadow may not be visible. So, for example, when shading (lighting) is turned on, it is not possible to cast a white shadow on a dark surface. To override this effect, you must disable shading. For more about using shadows without lights, see Shadows Without Lights.

Shadow Parameters in the Properties Tab

Every visible object in a 3D space will have shadow controls in the Properties tab of its Inspector. This includes shapes, clips, particles, and so on. Lights, Cameras, and 2D groups at the root level of the project do not have shadow controls.

  • Cast Shadows: This checkbox sets whether or not an object will cast a shadow if it is between a light source and another object.
    Figure. Canvas showing an object casting a shadow.
  • Receive Shadows: This checkbox controls whether or not neighboring objects’ shadows will affect the current object. When deselected, light will affect the object as if the shadow-casting object did not exist. The following image depicts an object (the white ring) with the Receive Shadow checkbox selected and the Casts Shadow checkbox deselected.
    Figure. Canvas showing an object receiving a shadow.
  • Shadows Only: This checkbox allows an object to block light and cast a shadow, while the object itself does not appear in the scene.
    Figure. Canvas showing an object casting a shadow but not visible itself.

    You can select both Receives Shadows and Shadows Only, which makes the object invisible except for the regions where a shadow is cast upon it.

    Figure. Canvas showing object with both Receive Shadows and Shadows Only selected.

Shadows and Complex 3D Objects

When using shadows with objects such as particle systems, text objects, or replicators that are set to 3D, shadows will be cast from one part of the object onto another part. This is called self-shadowing.

Figure. Canvas showing examples of self-shadowing.

Modifying the object in a way that causes rasterization prevents shadows from being displayed.

Figure. Canvas showing self-shadowing disabled when layers are rasterized.

In some cases you may be able to find another way to perform the effect that will not require rasterization. For example, in the following images, rather than modifying the opacity of the particle emitter, which causes rasterization, you can modify the opacity of the particle cells, creating the desired effect and maintaining the desired shadows.

Figure. Canvas showing effect of opacity adjustments on particle systems.

Note that in the second figure, the layer order of the particle system has been affected, and all particles now appear in front of the letter A. For more about how rasterization affects shadows, see Shadows and Rasterization.

Shadows Without Lights

Lighting and shadows can each be disabled independently. You can keep shadows visible, even when lighting is disabled, allowing you to keep the original unshaded look of the scene. Turning off lighting also changes the way shadows are rendered.

When Shading (the visible effect of lighting) is disabled, shadows behave differently. Rather than being multiplied with the object upon which they are cast, the shadow’s color and opacity are controlled only by the Shadows settings in the Light tab of the shadow-casting light’s Inspector.

Figure. Canvas showing shadow with and without shading enabled.

This enables you to create shadows of any color or opacity, from traditional dark shadows to brightly colored or even white shadows.

Figure. Canvas showing different color shadows with shading disabled.

Shading can be disabled globally by choosing View > Render Options > Lighting (Option-L) or by choosing Lighting in the Render pop-up menu above the Canvas (make sure there is no checkmark beside the menu item). It can also be disabled for a specific object in the Lighting section of an object’s Properties tab. For more about disabling lighting/shading see Disabling Lighting.

Figure. Canvas showing shading disabled globally, and disabled on an individual object.

With Spot lights, enabling shadows but disabling shading can create an seemingly strange result where the shadow is suddenly cut off because it has exceeded the scope of the light cone. Because the shading effect of the light cone is turned off, the shadow edge looks unnatural.

Figure. Canvas showing a spot light casting a shadow that exceeds its cone, when lights are turned off.

To correct such an occurrence, simply increase the Cone Angle in the Light Inspector.

Disabling Shadows

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

To disable rendering of shadows