FEofSG
by Tim C. Lueth, SG-Lib Toolbox: SolidGeometry 5.6 - FS/Feature Surfaces
Introduced first in SolidGeometry 3.8, Creation date: 2017-04-06, Last change: 2025-09-14
returns FE and optional VL of a solid geometry or of gca
Description
ATTENTION: Matlabs feature edges need not to have the same direction even if there is only feature edge contour. To create a closed polygon CVL you have to resort the edges first.
See Also: VLFLofgca
, FEplot
, ELsort
, ELreconnect
Example Illustration
Syntax
[FE,VL]=FEofSG([SG,ang])
Input Parameter
SG: | | if empty; VLFLofgca is used |
ang: | | angle; default is 0.4 ~ pi/8 |
Output Parameter
FE: | | Feature edge list |
VL: | | Vertex list for embedded SG |
Examples
FEofSG(SGsample(3))
A=SGsample(19); FEofSG(A); EL=ans; VLELplots(A.VL,EL,'r-',4,2); view(80,-10)
A=SGsample(19); FEofSG(A); EL=ELsort(ans); VLELplots(A.VL,EL,'r-',4,2); view(80,-10)
Copyright 2017-2025 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, FEofSG, is designed to extract feature edges from a solid geometry (SG) object. It can also work with the current axes (gca) if no SG is provided.
Input Parameters
- SG: The solid geometry object. If empty, the function uses
VLFLofgca to obtain vertex and face lists from the current axes.
- ang: The angle threshold for detecting feature edges. The default value is 0.75 radians.
- nf: Not explicitly used in the function, but can be provided as a third argument.
- esort: A boolean flag indicating whether to sort the feature edges. It is determined by the fourth argument or defaults to true.
Output Results
- FE: The list of feature edges detected in the solid geometry.
- VL: The vertex list associated with the solid geometry.
Algorithm Steps
- If no input arguments are provided, the function retrieves vertex and face lists from the current axes using
VLFLofgca.
- It extracts the vertex list (VL) and face list (FL) from the solid geometry using
VLFLofSG.
- A triangulation object,
TR3, is created using the face and vertex lists.
- Feature edges are detected using the
featureEdges function with the specified angle threshold.
- If
esort is true, the feature edges are sorted using ELsortFE.
- If no output arguments are specified, the function plots the solid geometry and its feature edges using various plotting functions.
Algorithm explaination created using ChatGPT on 2025-08-19 08:08. (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