edgeNormal

by Tim C. Lueth, SG-Lib Toolbox: SolidGeometry 5.6 - Geometric Queries
Introduced first in SolidGeometry 2.4, Creation date: 2015-08-01, Last change: 2025-09-14

returns the edge normals of surface boundaries

Description

This function is in fact "edge-starting-vertex-orthogonal-vector" and returns a list of the selected vertices vi
In case of a planar or freeform surface that is not closed(!) there exist a border line (freeBoundary). This function calculates the normal vectors of the edge list vertices, i.e. the cross product of the line from the previous to the next vertex of a vertex of an edge with the normal vector of this vertic on the surface.

See Also: edgeNormal , CPLedgeNormal , VLedgeNormal , PLnorm , PLELnorm

Example Illustration

missing image of edgeNormal(VL,VNL,EL)

Syntax

[VOL,c]=edgeNormal(VL,VNL,[EL])

Input Parameter

VL: Vertex list (nx3)
VNL: Vertex normal list (nx3) (i.e. vertexNormal)
EL: Edge list (i.e. freeBoundary)

Output Parameter

VOL: Vertex orthogonal vector of the starting vertex in the edge list
c: starting vertex index list = EL(:,1)

Examples

[SG,FLW]=SGsphere(10,'',pi/3,-pi/3); SG.FL=FLW;
SG=SGtransR(SG,rot(pi/6,0,0)); SGfigure(SG); view(-30,30); VL=SG.VL; FL=SG.FL;
[VL,FL]=PLFLofCPLdelaunay(PLcircle(1)); VL=VLaddz(VL);
TR3=triangulation(FL,VL);
NL=vertexNormal(TR3);
EL=freeBoundary(TR3);
edgeNormal(VL,NL,EL)
h=SGplot(SG); setplotlight(h,'w',0.1);



Copyright 2015-2025 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

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