NURBS surface from points

Replies to This Discussion

Permalink Reply by Michael Pryor on December 15, 2011 at 5:15pm

make it 21. U+1.

because you have 20 divisions in the U direction, but 21 points, because of the end points on the surface edge. 

Permalink Reply by Ivy Hume on December 15, 2011 at 5:19pm

20 is my U+1. Anyway, I tried 19, 20, and 21-- I tried everything and all I see is red. I'll try to upload it again. Do I need to include some sort of vector conversion?

Permalink Reply by Chris Tietjen on December 15, 2011 at 5:44pm

Hi Ivy,

Flatten the point list at the surface input.

Chris

Permalink Reply by Ivy Hume on December 16, 2011 at 10:20am

That worked, but now I have a flat plane. I would like my plane to conform to the grid points as they are set after I moved them. This is why "flattening" does not achieve the final product I'm looking for. I would like the surface to curve... How else can I manipulate the points of a nurbs surface?

thank you! 

Permalink Reply by Brian Harms on December 16, 2011 at 11:00am

You could interpolate a curve through each row of your grid of points and then loft the curves. The surface would then update as the points move.

Permalink Reply by M NICK on February 21, 2012 at 10:34pm

Brian, 

Could you please tell me how to make a NURBS curve through each row of a grid of points? or through a list of points?

Thanks

Permalink Reply by Brian Harms on February 21, 2012 at 10:50pm

Sure, it would be easier if you could upload a file you are working with - just because I'm not sure exactly how you are generating your points.

In general it's just list management. You can do this a few different ways (using series + list items, sublists, path mappers...)

Permalink Reply by M NICK on February 22, 2012 at 5:58pm

Brian, 

I have for example a text files, like the file I uploaded, these are a series of numbers generated randomly, I want make a NURBS curve for each row. 

Thanks for your help:)

Permalink Reply by M NICK on February 22, 2012 at 6:24pm

This is a text file

Attachments:

• points.txt, 1 KB

Permalink Reply by Chris Tietjen on December 16, 2011 at 11:21am

I thought you were just stuck on getting the surface to generate.  Here it is with unique Z-vectors.  If you need more help it would be good if you posted your definition.  Guessing is the hard part.

Chris

Attachments:

• UndulatingSurface.gh, 5 KB

Permalink Reply by Chris Hanley on December 16, 2011 at 12:04pm

Chris T has described the solution you are looking for.  

Here is a very minor variation on that theme, using the good old image sampler.  Attached are the example files with some notes on what is going on.  

if you want, you can read through the notes.  They are intended to explain a few things, as well as pose a question or two!

Attachments:

• SurfaceFromPoints_ExampleCAH.3dm, 26 KB
• SurfaceFromPoints_ExampleCAH.gh, 119 KB

Permalink Reply by pwdarden on September 18, 2013 at 3:54pm

Hi Chris, 

I am also working with a similar issue.  I have a list of points (in text format), and i'd like to make a surface with them, ensuring that i can change the z value as needed.  I'm looking at your gh file at the moment and I am confused by the image sampler and its role in the script.  Basically, I'd just like to do what I've stated above.  With this script is it possible to change it so that each point can be assigned different values in the z direction?  Seems simple, but I'm unsure how to make it happen.  Any advice would be helpful!  

Thank you, 

Prentiss