User guide

Charnwood Dynamics Ltd. Coda cx1 User Guide – Coda Basics I - 1
CX1 USER GUIDE - COMPLETE.doc 26/04/04 36/162
When creating alignment transforms for two Codas, place the marker boxes flat on the
floor. Or, if you get warnings of markers going out of view when aligning each Coda
separately, point the control boxes at each Coda in turn. (This may happen if you are
using the Codas in a very large space with a high ceiling. During the alignment
procedure, each Coda strobes separately.)
Using an Alignment Transform
The use of a (stored) alignment transform when displaying or acquiring marker co-
ordinates is determined in the Acquisition Setup dialog by the Co-ordinate Transform
selection (CODA menu: Acquisition Setup… command).
After creating and storing alignment transforms, the Co-ordinate Transform selection is
automatically set to ‘CodaAlignment’. This selection is stored in the Codamotion Analysis
Setup file (Setup: Save Setup…).
When Codamotion Analysis is started with an ‘Aligned’ configuration of two Codas, the
stored transformation matrices are re-loaded and will be used automatically if the
Acquisition Setup specifies ‘CodaAlignment’ in the Co-ordinate Transform box. Data
acquisition is disabled if the ‘CodaAlignment’ transform is not selected or is unavailable
when using an ‘Aligned’ configuration.
Remember that the transform matrix will be invalid if either Coda has been moved.
There is no automatic warning of misalignment of two Codas, but the real-time marker
display will show a large error value (in the fourth column) for markers visible to both
Codas.
Checking the Alignment
For markers visible to both Codas simultaneously, an error value is displayed in the real-
time marker display. This is the Euclidean distance between the co-ordinates of the
marker measured by each Coda. However, for a marker to be visible to both Codas
simultaneously, it may be at a high angle to one or both, and so the co-ordinate value may
be inaccurate.
Aligning Multiple Codas
Multiple Codas must be aligned to each other and to a room (walkway) co-ordinate frame
by creating alignment transformation (rotation) matrices for each Coda.
If alignment transform matrices are created, they are stored in text files
C:\Codamotion\Coda\CXxxxx-Alignment.dat (where xxxx is the Coda unit serial number)
and can be used in subsequent measurement sessions if the Codas have not been
moved.
Creating an Alignment Transform
When the Codas are positioned in an arbitrary orientation to the room and/or to each
other, and the markers defining the co-ordinate axes are made visible to all Codas, it is
possible to create alignment transforms for all Codas simultaneously by selecting the
Align Coda… command on the CODA menu, and checking the appropriate boxes in the
Alignment dialog.