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[zell_winston <>]

Hi houssen, 

As far as my knowledge goes, geometric libraries dont usually provide the "Intersection of a pair of 3D lines". This is because the high possibility that 3D lines are not intersected at all. 

Instead, in computational geometry theory, we usually discuss the closest distance between two 3D lines. If the distance is smaller than your predefined tolerance, you can assume it to be intersected. 

I haven't check the CGAL context for detail. Hope this quick message will help you.

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zell_winston

 

From: houssen

Date: 2015-11-13 01:38

To: 

Subject: [cgal-discuss] Intersect lines with lines, and, polygons with polygons in 3D space

Hello,

 

I need to intersect polygons, or lines, made of 3D points : is this

possible with CGAL ?

 

I am new to CGAL.

 

First, I checked out the doc to intersect polygons, or lines, made of

2D points (x, y):

http://doc.cgal.org/latest/Sweep_line_2/index.html

http://doc.cgal.org/latest/Boolean_set_operations_2/index.html (in

particular section 3.3)

I went accross the tutorials without any problem using Point_2,

Segment_2 and Polygon_2.

 

Then, I looked at the doc related to using 3D points instead of 2D

points (http://doc.cgal.org/latest/Polygon/index.html - section 2.3): it

seems at least some operations are possible (for example, is_simple).

 

Now, I try to turn my basic tutorial into 3D space : basically, I tried

to replace Point_2 by Point_3, Segment_2 by Segment_3, Polygon_2 by

Polygon_3 the "naive" way, this seems not to be possible.

CGAL::compute_subcurves turns out to be unable to support Segment_3,

right ? Also Polygon_3 does not seem to exist ! :D

 

Can I compute intersections of polygons, or lines, made of 3D points

(x, y, z) with CGAL ?

 

Franck

 

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