Algorithm (Workflow)

This function, VLswapY, is designed to mirror a list of 2D or 3D vertices along the y-axis. It is part of the SolidGeometry library and was introduced by Tim Lueth in 2013.

Input Parameters

• VL: This is the input vertex list. It is a matrix where each row represents a vertex. The columns correspond to the x, y, and possibly z coordinates of the vertices.

Output Results

• RVL: This is the resulting vertex list after mirroring the input vertices along the y-axis.

Algorithm Explanation

The function begins by copying the input vertex list VL to the output variable RVL. This ensures that the original list is not modified.

The core operation of the function is performed in the line:

RVL=[RVL(:,1) -RVL(:,2) RVL(:,3:size(RVL,2))];

This line constructs a new matrix for RVL by performing the following operations:

• RVL(:,1): This extracts the first column of RVL, which corresponds to the x-coordinates of the vertices. These coordinates remain unchanged.
• -RVL(:,2): This negates the second column of RVL, which corresponds to the y-coordinates of the vertices. Negating these values effectively mirrors the vertices along the y-axis.
• RVL(:,3:size(RVL,2)): This extracts all columns from the third to the last, which correspond to the z-coordinates (if present) and any additional dimensions. These coordinates remain unchanged.

The function does not contain any conditional statements or switch cases, making its operation straightforward and efficient for the task of mirroring vertices along the y-axis.