Detect polygon and polyhedron from lines in 3D

Hello

I have a lot of lines in 3D,and want to find the closed loop to detect polygonal surfaces.

After i get polygonal surfaces

How to find close space to detect polyhedron?

What the concept is ?

By the way, the lines are large number.

I attach the node .csv file ,and it means the start point and endpoint of the line.

Thank you for any advices.

Attachments:

node1.csv, 428 KB
node2.csv, 426 KB

Replies to This Discussion

Permalink Reply by Laurent DELRIEU on May 14, 2016 at 2:55pm

Hello

not an easy task ! The first one was to put your points in Excel and to Grasshopper. Internalize date in grasshopper it is more simple for helping.

At the moment I have no clear solutions, I began to make a bit of topology. Here is the script, it is similar to sandbox. It gives relation between points (line 1 is with point X and Y)

Point YY is linked with points a b c ...

So an algorithm could be begin with a point, choose 2 lines connected to this point find next point connected to these line and not to far from the plane generated by the plane defined by the first 2 lines continue until you close the loop or before counting xx points so you will have faces and after that ??

Attachments:

Excel_read_polygon.gh, 230 KB

Permalink Reply by Laurent DELRIEU on May 16, 2016 at 4:01am

Hello,

I continue to work a bit on this. It is not simple, it works now for a low (very low :() number of lines.

I changed the logic, I choose first a point, then 2 points connected to it. So it is used to calculate a direction of a plane containing the 3 points. After that next points are tested if they have quite the same direction as the first plane. There is a recursion if it works. Recursion end

if limit in size is obtained (no polygon with more than xx points)

if angle is too big

if the next point is the same as the beginning of polygon.

The problem now is that it generates many polygons on the same place. It could (must) be filtered.

Here an example with 3 twisted hexagon (5°, 10° and 15°). Depending on angle threshold there is not the same number of same hexagon on each one.

Attachments:

lines_to_polygons_published.gh, 233 KB

Permalink Reply by Tommy Su on May 18, 2016 at 3:04am

Thanks for your reply.I have to spend more time to understand your code.

I try another way that is from another discussion.

Use the Weaverbird's mesh and then split the mesh,

but the problem is that it got only triangle and quadrangle.

Attachments:

lines set.gh, 8 KB

Permalink Reply by Kim hauer on May 18, 2016 at 4:51pm

Yikes! .....I don't understand what you are trying to derive out of this plethora of Planes Tommy, however it does make for an interesting cube of stuff :)