This is an area in which C-Motion and VICON agree to disagree.

A few Visual3D customers have requested that we export C3D files containing information pertinent to Polygon. If it weren't for these requests from our customers, we would not have done this because we do not approve of putting PROCESSED data into the C3D file.

POLYGON requires additional information than that contained in a typical C3D file. Visual3D exports LINK_MODEL_BASED signals, and context dependent EVENT LABELS to POLYGON allowing Kinematic and Kinetic data to be reported in POLYGON. Animating objects in POLYGON requires additional data and an additional file to be created by Visual3D. Visual3D, therefore, creates additional landmarks for defining the position and orientation of a segment, and an MKR file defining which wireframe objects are associated with the segments.

Select the following option under the File Menu:

Export –> Export C3D File for Vicon Polygon

or use the Export_Polygon_C3DFile pipeline command.

Remove_Prefix_From_Point_Labels
! /OVERWRITE_C3D_FILE=FALSE;

Vicon Corporation's Workstation software provides an option to add a prefix to all of the marker labels. This causes Visual3D a big problem because Visual3D assumes that markers are named consistently between files, especially between the standing trial and the movement trials. The following commands allows the user to remove the prefix from the marker names.

The C3D file format is a public document (http://www.c3d.org) that most hardware vendors currently export. We are only aware of one implementation of the format that has an inconsistency that Visual3D must handle explicitly.

The FORCE_PLATFORM:ORIGIN parameter (within the PARAMETER SECTION of the C3D file) describes the location of the working surface of the force platform relative to the force platform coordinate system. For AMTI force platforms the z-value of the origin should be a negative value. Visual3D can correct this value automatically should it read a positive value.

Should the user not want to have the program correct this value automatically, a dialog is available under the Properties menu item labeled “Use correct FORCE_PLATFORM:ORIGIN vector”. In this dialog the user can select the check box “Perform automatic correction”(the default).