Algorithm (Workflow)

This function, SGvaryfrom, is designed to modify a solid geometry by slightly adjusting its vertex coordinates. This adjustment helps to mitigate issues with boolean operations and numerical precision in MATLAB's 64-bit environment, particularly when using Delaunay triangulation.

Input Parameters

• SG: The solid geometry object that needs modification. It is expected to be a structured data type representing a 3D solid.
• varargin: Additional optional parameters that can be passed to the function, though not explicitly used in the provided code.

Output

• SGN: The modified solid geometry object with slightly adjusted vertex coordinates.

Algorithm Steps

1. The function begins by calling SGofSG(SG), which likely creates a copy or a new instance of the solid geometry object SG. This is stored in SGN.
2. The vertex list of SGN is then modified by calling VLvaryfrom(SGN.VL, varargin{:}). This function is responsible for adding small deterministic values to the vertices, effectively "jittering" them to avoid precision issues.
3. If no output is requested (i.e., nargout == 0), the function will plot the modified solid using SGfigure(-30,30) and SGTplotalpha(SGN). This visualization step is useful for verifying the changes made to the solid.

Example Usage

The function can be used with different types of solid geometries:

• For a natural solid, such as ADAM_Aframes, the function will likely make only minor changes.
• For an ideal geometry, like SGbox, almost all coordinates may be adjusted.

This function is part of a set of functions aimed at improving the robustness of geometric operations in MATLAB, particularly when dealing with complex boolean operations.