How to generate motion vector fields by using the VectorGenerator node

The VectorGenerator node in NukeX is used to create the images with the motion vector fields. This node generates two sets of motion vectors for each frame which are stored in the vector channels. The output of the VectorGenerator node can be used with the nodes that take vector input such as the Kronos and MotionBlur nodes. The image with the fields contains an offset (x, y) per pixel. These offset values are used to wrap a neighboring frame into the current frame. Most of the frames in the sequence will have two neighbors therefore two vector fields are generated for each frame: backward vector and forward vector fields.

To add a VectorGenerator node to the Node Graph panel, select the node in the Node Graph panel from which you need to generate fields and then choose VectorGenerator from the Time menu; the VectorGenerator# node will be added to the Node Graph panel. Make sure the VectorGenerator# node is selected and then press 1 to view its output in the Viewer# panel. To view the forward motion vectors, select forward from the Channel Sets drop-down. Select backward from the Channel Sets drop-down to view the backward motion vectors. To view the backward and forward motion vectors, choose motion from the Channel Sets drop-down. Figure 1 through 4 show the input image, forward and backward motion vectors, forward, and backward motion vectors, respectively.