Plot Frame

RTSX Help: Plot frames in a transformation chain


PlotFrame( ) provides a more systematic way to visualize a sequence of homogeneous transformations than trplot( ). A tranformation chain must be passed to the function instead of a homogeneous transformation matrix.


  • PlotFrame(fc, options)

Input Arguments

  • fc  — a chain of completed coordinate frames created by SerialFrame( )

Output Arguments

  • none


Note : options in [ ] must be passed to the function in pairs.

  • ‘grid’ — show grid
  • ‘oinfo’ — show origin location (could look messy when several frames are condensed together)
  • [ ‘figure’, fnum] — command the plot to a particular window indicated by fnum


To study robot kinematics, one must understand clearly the basic of kinematic chain connecting coordinate frames together. PlotFrame( ) serves as a convenient graphical tool to visualize such a chain. The function accepts a completed chain created by SerialFrame( ) . An incomplete chain must be resolved first by ResolveFrame( ), if possible. Unlike trplot( ) where a user has control over a frame’s axis color and line style, PlotFrame( ) assigns colors to frames automatically depending on their positions in the chain.


The example below shows the necessary steps from frame creation to plotting. The result is shown in Figure 1 below.

// first create a sequence of frames
clear F;
F(2)=Frame(trotx(pi/2)*transl([0 1 1]),'name','V'); 
F(3)=Frame(trotz(pi/4)*transl([2 3 -1]),'name','W');  
fc=SerialFrame(F,'name','Chain 1');

Figure 1: transformation chain plot example with PlotFrame( )

See Also