Algorithm (Workflow)

This function, SGisinternalframe, determines whether a given frame is internal to a solid geometry. It is part of the SolidGeometry library and was introduced in version 5.0.

Input Parameters

• SG: Represents the solid geometry. It can be a single solid or a cell array of solids.
• T: A 4x4 transformation matrix representing the frame to be checked.
• varargin: Additional optional parameters, though not used in this function.

Output

• VIL: A binary indicator where 1 means the frame is internal, and 0 means it is external.

Algorithm Steps

1. Call the function SGisInterior with SG and T to determine if the frame is internal. This function returns a cell array.
2. Convert the cell array result from SGisInterior to a matrix using cell2mat and cell2cellarray.
3. If no output is requested (nargout==0), proceed to visualization:
• Set up a figure with SGfigure and plot the frame using tplot.
• Add annotations to the plot indicating internal frames in green and external frames in other colors.
• If SG is a cell array, iterate over each solid:
• Use SGplotalpha to plot each solid with transparency, using green for internal frames and other colors for external frames.
• If SG is a single solid, plot it with SGplotalpha using green for internal and red for external frames.

Example Usage

Load a set of frames from a file and check if specific frames are internal or external:

load ADAM_Aframes.mat; SG=ADAM_Aframes
SGTcut(SG,'KL',0.1); X=ans
SGisinternalframe(X,SGTget(SG,'KL'))     % KL is outward frame for one solid
SGisinternalframe(X,SGTget(SG,'AL'))     % AL is an internal frame