Grasshopper

algorithmic modeling for Rhino

Average plane / plane fit

Hi

 

Does anyone have a good idea on how to find an average/mean plane through a surface?

The surface is doublecurved and has 4 corner points.

 

I've previously used the following three methods, but I need some inspiration on other methods.

 

1: Corner points

I've used corner points, both diagonal and consecutive points to create x and y vectors and created a plane from these.

 

2: Summation of normals vectors from sampling points

I've tried to create a grid of 50x50 points on the surface. Used each point to sample the normal vector in it. Add'ed all vectors and used this as normal vector for a plane,

 

3: Galapagos

I used Galapagos to rotate a bounding box around the surface until I got the bounding box with the smallest height. I then placed a plane through the mid of the height of the the box.

 

In the project I'm working on I cannot use Galapagos. Do you have any suggestions of other methods to approximate an average plane through a surface.

 

EDIT:

I know the plane fit component but I'm searching for manuel ways to do it. Does anyone know how it's done in the plane fit component?

 

Regards,

Thomas

Views: 5303

Replies to This Discussion

Permalink Reply by Danny Boyes on October 21, 2011 at 3:22am

Have you tried the component [Plane Fit]

Permalink Reply by Thomas Bildsøe on October 21, 2011 at 3:23am

 

Thanks, Yes I know it. Do you know how it works? I want to create the functionality manually?

Permalink Reply by Danny Boyes on October 21, 2011 at 3:40am

I did answer your original question :)

Have you come across either Least Squares or Principal component analysis? Heavy maths if you're up to it.

Permalink Reply by Thomas Bildsøe on October 21, 2011 at 3:45am

 

Yep, you did :)

 

And thanks for the two links, I think this is what I'm looking for. I will have to see if it proves too difficult for me, but I'm gonna try :)

Permalink Reply by Danny Boyes on October 21, 2011 at 3:48am

I also came across this on Stack overflow

Permalink Reply by Thomas Bildsøe on October 21, 2011 at 4:40am

Thanks, this is really usefull :)

Permalink Reply by Sam Wood on October 21, 2011 at 3:23am

Hey I don't know of a manual way of doing it like you say, but this can easily be done on Kangaroo - hope this helps.

 

Attachments:
Permalink Reply by Thomas Bildsøe on October 21, 2011 at 3:32am

Thanks,

 

I really like this method, but I still need the manual way of doing it. But I'm definetly going to use some more time on Kangaroo.

 

 

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