Introduction

The TWIXTOR technology is now available in Softimage|XSI version 4.0 and above.
You will need the FXtree to use TWIXTOR and MOTION VECTORS Create.
We strongly recommand to use XSI 4.2 or 5.0 or over (XSI 4.2 is a free upgrade from 4.0).

TWIXTOR for xsi is composed of two ufo's that works in the FXtree :

• TWIXTOR : Intelligently slows down and speed up your image sequences.
• MOTION VECTORS Create : Allows you to export the motion estimated optical flow of an image sequence.

Documentation index

• installing TWIXTOR
• license info
• using TWIXTOR in XSI
• using TWIXTOR with Motion Vectors in XSI
• tutorials and exemple scenes
• helping TWIXTOR with 2D and 3D Geometry (points and curves)
• more about motion vector format
• rendering motion vectors with Mental Ray

How Twixtor Works?

Twixtor enables you to "time warp" your image sequences with visually stunning results. In order to achieve its unparalleled image quality, Twixtor synthesizes unique new frames by warping and interpolating frames of the original sequence... employing RE:Vision's proprietary tracking technology that calculates motion for each individual pixel.

Twixtor Features:

• Calculation of motion vectors at each pixel
  
• Warping and interpolation of frames to "time warp" input footage
  
• Compatible with XSI processing of fields providing more options for multi-frame rate outputs
  
• Time stretching of a sequence using a single scaling parameter
  
• Keyframeable retiming for complete control on a frame-by-frame basis.
  
• Ability to mark cut points so that material with edits can be retimed or transcoded without breaking the material into pieces first
  
• Twixtor allows you to guide Twixtor's tracking on problematic footage via multiple complementary methods.
  
• Ability to separate the source material into a foreground and a background layer that are inbetweened individually. Layers in Twixtor Pro are specified through the use of a matte channel that you create (independently of Twixtor). Separate layers are particularly useful when objects in the scene cross each other. With the export background only or foreground only option, one can also cascade the process through different Twixtor if more layering is needed
  
• Up to 12 user defined tracking points can be specified to help guide Twixtor's motion estimation. As well, 4 UFO trackers operator result can be piped into Twixtor. By using the tracking points you can explicitly tell Twixtor where a pixel moves from one frame to the next in order to guide Twixtor's calculation of motion vectors. You can set the position of each point at each frame by hand, but more importantly, these points can be positioned from frame-to-frame using the host application's point-tracking features, when available.
• The Motion Vectors Create operator provides the option to output the per-pixel motion vectors that are calculated.
  
• Twixtor can remap time using motion vectors supplied. Motion vectors can come from many places, such as a 3D animation system or from the Motion Vector Create output plugin.
• Twixtor can as well be guided by 3D points and curves coming from the 3D Scene, for example if you have 3D tracked a sequence, laying down registration lines in 3D will enhance Twixtor precision or simply permit more extreme view changes.
  

Twixtor supports both 8, 16 bits and floating point pixel processing. The latest information about RE:Vision Effects products is always available on our website.

Please Note, when the plugin is loaded in FXtree, a menu item "About TWIXTOR" shows up in XSI main Help menu. This will give you easy access to the latest info, doc and tutorials.