Motion blur is an optical phenomenon that occurs when an object moves fast in front of a camera: the object looks blurred as it crosses the frame. Maya Software rendering renders out motion blur in two ways—2D blur or 3D blur—although neither will render as reflections:
- In the 2D blur process, Maya calculates after the frame is rendered. Any objects moving in the frame are blurred with a 2D filter effect. The 2D blur is effective for most applications and faster than 3D blur.
- The 3D blur process is calculated while a frame of the sequence is rendering. Every motion-blur-enabled object is blurred with typically better results than 2D blur, but at a cost of a much longer render time.
We’ll briefly cover motion blur in mental ray for Maya later in the chapter.
To enable motion blur for the Maya Software renderer, open the Render Settings window. In the Motion Blur section in the Maya Software tab, click the Motion Blur check box. Then, choose 2D or 3D blur.
Typically, you control the amount of blur rendered for 2D and 3D by setting the Blur By Frame attribute—the higher the number, the greater the blur. Using additional controls, however, you can increase or decrease the 2D blur effect in the render. The Blur Length attribute affects the streakiness of the blur to further increase or decrease the amount of motion blur set with the Blur By Frame attribute.
Use motion blur sparingly in most scenes. It takes a careful eye to choose the right blur amount for an object.
Setting a camera’s Shutter Angle attribute (in the camera’s Attribute Editor in the Special Effects section) also affects the amount of blur rendered—the higher the number, the greater the blur.