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[Vahid Azizi <>]

Sorry, i tried to keep the message so short. anyway, I am doing following steps:

1) I have some points which they are supposed to be a polyhedron, It is the result by delaunry triangulation over these points: polyhedron

2) i have another set of points which they are supposed to be a plane, after delanury triangulation over this set I have: plane

3) in last step i want to find the subsurface of the plane which is not in intersection with polyhedron. My idea here is to iterate over all triangles and keep all intersection points in a list, then i can create a convex hull out of intersection points. So, i have the subsurface which is in intersection with polyhedron. I did these steps for another purpose before and it works. I didn't try to extract the subsurface which is not in intersection but there must be a way for that.

Now, the problem is with explained idea as you see in this image, intersection function doesn't return any intersection points for upper red triangle(upper part of the plane) . But there are two intersection points for down red triangle which are marked with blue star. As i spent some time for finding the reason it seems the problem is this triangle doesn't have any intersection with edges of triangles in polyhedron. I think if i could change the resolution of triangulation i could solve this problem. If i have more fined triangles in polyhedron with high probability there will be intersection with their edges. As i searched it seems there is not any option for modifying resolution of triangulation. Also the fig file for this issue is uploaded here, maybe it could give you better view. 

My questions are:

Is there any better way to find the subsurface of the plane which is not in intersection with polyhedron? Here just assume i have to two 3D polyhedrons which i want to find the part which doesn't have intersection. 

if there is not any better way, how could i solve the current issue?

Thanks in advance,

Best,

On Tue, Nov 1, 2016 at 3:36 AM, Sebastien Loriot (GeometryFactory) <> wrote:

It is not clear (at least to me) what you are trying to do.
What are you looking for? An intersection function for 2 triangle soups?
A 3D constrained triangulation?

Sebastien.

On 11/01/2016 03:40 AM, Vahid Azizi wrote:

Hi all,

I have a geometry volume and a plane(their vertices), the Delaunry
triangulation is applied on both of them(their vertices). For the
geometry volume i get 16 facets and for the plane i get two facets. I
need to find intersection between these two. It seems in some case the
plane which is inside the volume doesn't have intersection with any
facets of volume. I searched for changing resolution of triangulation
but it seems there is not such a option. I've attached an image which
depicts the situation and also a fig file which you can rotate the image
to see what is the problem. The blue stars are intersection points for
down red triangle.

images:
https://drive.google.com/drive/folders/0B6aDrBbewOPBR2gwTE5JZm4yNnc?usp=sharing

Is there anything that i can do, maybe with resolution or with
intersection or do i need to go with another approach?

Thanks in advance!

Best,
--
/Vahid/

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Vahid