The ‘Spatial Jitter At’ knob allows you to control at which sample levels ScanlineRender2 will jitter spatial subpixel locations when doing anti aliasing so that you break up the patterns for better results.

By default the location of the sampling within the pixel itself is being randomly changed at a value of 2 or higher, so only turns on when samples are above 1. When turned off only the exact centre of the pixel is being sampled when samples is 1, or in a uniform grid if greater than 1. This means you have control over which sample levels have uniform sampling (samples at a value less than the ‘Spatial Jitter At’ value) or jittered sampling (samples at a value equal to or more than the ‘‘Spatial Jitter At’ value).

Time Jitter At

The ‘Time Jitter At’ knob determines at what sample number you start randomly jittering the time for motion blur.

The default value is 2, which means jittering to produce motion blur occurs when samples are at a value 2 or higher. If samples are at 1, no motion blur will be created, but motion vectors will be produced so that you can still blur the image.

Scene Time Offset

The ‘Scene Time Offset’ knob allows you to shift the frame you are rendering and can be done in subframe increments.

This means you can slip your render in time (with subframe accuracy) without affecting the camera or the objects in the stage, which can be really helpful when you are trying to slip the camera to get vector motion blur aligned properly.

Camera Xform

The ‘Camera Xform’ knob enables and disables the motion blur of a camera being transformed i.e. animating a Camera through space

Please note that subsampling matrices produce artifacts currently, as this requires quaternions for the matrix interpolation method which has not yet been implemented. As a workaround increase the Shutter Segments to chop up the frame you are generating the matrix for, into multiple matrices.

Camera Lens

The ‘Camera Lens’ knob enables and disables the motion blur of a camera projection control being changed i.e. motion blur generated from animating the focal length of the camera

Object Xform

The ‘Object Xform’ knob enables and disables the motion blur of an object being transformed i.e. animating a GeoCube through space (the mesh transform matrix is animated)

Object Deform

The ‘Object Deform’ knob enables and disables the motion blur of an object being deformed i.e. an animated radius knob on a GeoSphere (the point xyz locations are animated)

Lights

The ‘Lights’ knob enables and disables the motion blur of a light being transformed i.e. animating a light through space.

The ‘Shutter’ knob is how long the shutter should be open for when motion blurring.

Shutter Offset

The ‘Shutter Offset’ knob is how the shutter behaves with respect to the current frame value.

• centered: acts as a snapshot in the middle of the frame, so motion blur would be shown as if you paused halfway through the frame

• start: opens the shutter at the start of the frame, so you see the motion blur ahead of the geo animation

• end: opens the shutter at the end of the frame, so you see the motion blur after the geo animation

• custom: opens the shutter at a time specified by the user

Nuke has always defaulted to ‘start’ and going forward in time, so at a given frame the shutter is open. However often it can be useful to change this to ‘end’ when you want a motion blur trail to an impact point on a specific frame.

Shutter Segments

The ‘Shutter Segments’ knob is the number of time 'segments' used to interpolate motion blur. The greater the number of segments the greater the quality of rotational motion blur.

This helps with rotational motion blur, which gives more realistic results for motion blur on objects with rotational movement like, car wheels, helicopter blades etc.

Shutter Bias

The ‘Shutter Bias’ knob moves your motion blur to be weighted more to the start of a frame or end of a frame, or one end of the shutter.