SGgetCenterPoint

by Tim C. Lueth, SG-Lib Toolbox: SolidGeometry 5.6 - Analytical Geometry
Introduced first in SolidGeometry 3.1, Creation date: 2016-12-04, Last change: 2025-09-14

returns a point in the center of all vertices

Description

used as simple mass center approximation. At later stage it makes sense to calculate it using SGarea and facet based

See Also: SGarea

Example Illustration

Syntax

p=SGgetCenterPoint(A)

Input Parameter

A: Solid Geoemtry

Output Parameter

p: point

Copyright 2016-2025 Tim C. Lueth. All rights reserved. The code is the property of Tim C. Lueth and may not be redistributed or modified without explicit written permission. This software may be used free of charge for academic research and teaching purposes only. Commercial use, redistribution, modification, or reverse engineering is strictly prohibited. Access to source code is restricted and granted only under specific agreements. For licensing inquiries or commercial use, please contact: Tim C. Lueth

Algorithm (Workflow)

This function, SGgetCenterPoint, calculates the center point of a solid geometry based on its vertices. It is a simple approximation of the mass center.

Input Parameters

A: A structure representing the solid geometry. It contains a field VL, which is a matrix of vertices.

Output Results

p: A point representing the center of all vertices in the geometry.

Algorithm Steps

Calculate the bounding box of the vertices using the function BBofVL(A.VL). This function returns the minimum and maximum coordinates in each dimension.
Compute the center point p by averaging all the vertices in A.VL. This is done using the expression p = (sum(A.VL) / size(A.VL, 1)), which sums all vertex coordinates and divides by the number of vertices.
If no output is requested (i.e., nargout == 0), visualize the geometry and the center point:

Initialize a figure with SGfigure and set the view angle with view(-30,30).
Enable axis display with axis on.
Plot the solid geometry using SGplot(A, 'w'), where 'w' likely specifies the color or style.
Use zoompatch to adjust the view.
Add lighting with VLFLplotlight(1,0.5).
Plot the center point p as a star with size 5 using VLplot(p, '*', 5).
Draw lines from the bounding box edges to the center point using lplot for visual reference.

Algorithm explaination created using ChatGPT on 2025-08-18 23:11. (Please note: No guarantee for the correctness of this explanation)

Last html export of this page out of FM database by TL: 2025-09-21