Motion blur is a common phenomenon in photography, especially when capturing fast-moving objects. It occurs either when: a) the camera has moved, thereby the focal point is no longer the same from the time the camera shutter opens to the time the shutter closes (camera blur); or b) when the object is moving so fast that the camera’s shutter speed is not quick enough to capture a sharp image of the object (object motion blur). In OctaneRender®, motion blur effects are applied through the Animation rollout in the PBR Render Target. The scene also needs animated geometry in it (Figure 1).
Figure 1: The Animation settings in the PBR Render Target
The Animation Settings Parameters
FPS - Specifies the number of frames per second, where a frame is a different rendered image, each processed and shown consecutively to simulate motion within a scene.
Time - This specifies the shutter time percentage relative to the duration of a single frame, and it controls how much time the shutter stays open. You can set this to any value above 100% manually.
Shutter Alignment - Specifies how the shutter interval is aligned to the current time. This determines when the camera shutter is triggered. The options are Before, Symmetrical, or After, and they apply to each frame thereafter relative to the given frame rate (Figure 2).
Figure 2: Illustrating After, Before, and Symmetrical Shutter Alignment
Shutter Time - This specifies the shutter time percentage relative to the duration of a single frame. Shutter Time controls how much time the shutter stays open. You can set this parameter to any value above 100%.
Subframe Start/Subframe End - Specifies the approach, in terms of proportion (%) to simulate the camera’s shutter speed for that particular frame. OctaneRender uses Subframe Start and End percentages to render only a portion of a particular frame. If the scene has a lot of motion blur, OctaneRender uses these parameters to render only a piece of that motion blur. Values of 0% and 100% render the whole frame (default).
