Set the mv presets dropdown to set which renderer format to apply to the motion vectors. Each preset contains a scale and offset specific to the renderer, so that the vectors are in the format expected by Nuke. These should be the same channels as the channels you chose to create in step 3. Select the motion vector channels from the uv channels dropdown menu. In the VectorBlur properties, use the channels dropdown menu to select the channels to blur. Select Filter > VectorBlur to insert a VectorBlur node after ScanlineRender.Ī node tree with ScanlineRender and VectorBlur. You can increase this value later if non-linear movement cannot be approximated sufficiently well using VectorBlur’s linear approach. On the MultiSample tab, leave samples set to 1. If you view the channels you selected, you should see they now contain motion vectors. Use motion vector channels to select where to store the generated motion vectors. It also allows the VectorBlur node to produce the impression of curved motion blur by interpolating multiple samples of linear motion. This is the recommended option that usually produces the best results. distance - For every pixel, store the distance (in pixels) between samples in the motion vector channels.In order to have the same behavior as Nuke 6.3, set samples to 1. This option is only provided for backwards compatibility. velocity - Store the velocity of every single pixel in the motion vector channels (pre- Nuke 7.0 way).
This option is only provided for backwards compatibility, and isn't always accurate.
If you have moving objects in your scene but the camera is static, MotionBlur3D isn’t able to produce any output. However, note that MotionBlur3D only uses camera information to produce motion vectors. Alternatively, if your 3D scene is static or nearly so and the camera movement over the shutter time is nearly linear, you can also use the Filter > MotionBlur3D node.See To use VectorBlur with ScanlineRender or To use VectorBlur with RayRender. This is usually more accurate than using a MotionBlur3D node (described below), and works well with both static and moving cameras as well as both linear and non-linear camera movement. Use the ScanlineRender or RayRender nodes.
You can create the necessary motion vectors for use with VectorBlur in several ways: Compared to generating motion blur using the ScanlineRender node’s MultiSample controls, this is less accurate but faster to render.
Nuke’s VectorBlur node generates motion blur by blurring each pixel into a straight line, using the values from the motion vector channels (u and v channels) to determine the direction of the blur.