Algorithm (Workflow)

This function, VLofT, is designed to extract the origins of a list of 4x4 transformation matrices, which represent frames in 3D space. The function can handle both regular matrices and cell arrays of matrices.

Input Parameters

• TL: A list or cell list of 4x4 frames. It can be an [n*4 x 4] matrix or a cell array containing these matrices.

Output Results

• VL: A vertex list of the frame origins. This is a list of the translation components (the last column) of each 4x4 matrix in the input.

Algorithm Steps

1. Store the input TL in TLO for potential future use.
2. Check if TL is a cell array using iscell(TL):
• If TL is a cell array:
  • Convert the cell array to a regular matrix using cell2mat(TL).
  • Extract the first three rows of the matrix, which correspond to the rotational and translational components.
  • Identify the columns that contain the translation vectors (every fourth column) and extract them.
  • Transpose the result to get the vertex list VL.
• If TL is not a cell array:
  • Directly extract the fourth column of each 4x4 matrix, which contains the translation vectors.
  • Reshape the extracted data to ensure it is in the correct format.
  • Extract the first three rows, which are the x, y, z components of the translation vectors.
  • Transpose the result to get the vertex list VL.
  • Use squeeze(VL) to remove any singleton dimensions.
3. If no output argument is specified (nargout==0), visualize the result:
   • Call SGfigure(-30,30) to set up a figure for plotting.
   • Use hold on to allow multiple plots on the same figure.
   • Calculate the size of the bounding box using sofBB(BBofVL(VL)).
   • Plot the frames using tplot(TL,s/4,'','',''), where s/4 scales the plot.