About the intersection of planes

[ivanotero76]

I review other topics but, I didn't find information about this:

What about intersect of planes (I am interesting to intersection of three planes).

First of all I will try to extrack planes from my point cloud.

Then I will try to get points.

The points that are the intersection of those planes for example in a square classroom. Calculate the 8 points.

Could you type me some links that talk about this?

Thanks and best regards.

[daniel]

Well, CC will help you to fit the planes ont the point cloud... And that's about all ;)

You could of course sample points on one plane and then compute the distances to another plane to get the points that are close to 0 (approximately).

And for the maths there are many sites that will explain you how to compute the intersection between two planes (resulting in a line... or nothing). And then you can compute the intersection between the line and the third plane. It's generally full of degenerate cases so it's a little bit cumbersome.

[ccadiou01]

What about intersect of planes (I am interesting to intersection of three planes).

First of all I will try to extrack planes from my point cloud.

Then I will try to get points.

Hello,

You can use the RANSAC tool http://www.cloudcompare.org/doc/wiki/in ... n_(plugin) in order to extract the planes.
Then, export your plane in .dxf format.

plan.png (44.01 KiB) Viewed 4598 times

Then, open your planes with Sketchup pro (if you have Sketchup pro of course). Sketchup allows you to compute the intersection of three planes.
If you can't see any intersection between the plans, you can make them bigger in Autocad before exporting them in Sketchup.

Planes_in_Autocad.png (29.92 KiB) Viewed 4598 times

Indeed, the scale tool in Sketchup makes the planes bigger but it also modifies the orientation of the plane. You have a bigger plane, but it's not the same plane anymore. Autocad doesn't modify the orientation, only the size.

I only know this method, so I hope you have sketchup pro :p

[daniel]

Interesting. You can now also extend the plane size in CC (with the latest versions). See the 'Edit > Plane > Edit' method (or right click on the plane entry in the DB tree).

[ccadiou01]

You can now also extend the plane size in CC (with the latest versions).

Version 2.9 alpha?
I have version 2.7.0. I don't really trust alpha and beta versions. But maybe I'm wrong.
A few weeks ago I had version 2.6.3 beta and this version crashed sometimes, maybe because of the size of my clouds. Now with version 2.7.0, I don't have any problems.

[daniel]

The official version is now 2.8 (but for once 2.9.alpha is very good as it's mainly bugfixes of the 2.8 ;).

The 2.6.3 version is very old. 2.7 has more than 6 months.