Re:Vision effects has released a version of its Twixtor retiming software for Softimage|XSI. The plug-in runs as an FxTree operator within XSI and allows imported footage to be slowed down or sped up to fit with 3D elements within a scene.
Twixtor calculates the motion vectors of every pixel and allows the warping and interpolation of frames to 'time warp' input footage. Retiming can be keyframed by frame number or speed, and the tool has the ability to mark cuts points so that material with edits can be retimed without breaking the material into pieces first.
As well as working automatically, users can set up to 12 manual tracking points to help with difficult scenes. An extra four tracking points can be brought in from UFO tracker operators. There's support for a foreground-background separation matte for when cross objects make tracking problematic.
Remapping can be set to follow supplied motion vectors – for example, from a shader - and be guided by 3D points and curves taken from elsewhere in the 3D scene.
Twixtor for Softimage|XSI costs $695 (around £400). XSIbatch nodes for rendering cost $165 (around £95). It runs under the Essentials or Advanced versions of Softimage|XSI 4.0 or later, on Windows and Linux.