NURBS surface from a list of points

Replies to This Discussion

Permalink Reply by David Rutten on September 20, 2013 at 11:56am

If your points form a rectangular grid, then you can use the [Surface From Points] component. You only have to count how many points you have in the X direction.

If your points do not form a grid, then they cannot be used as surface control-points. In that case you'll have to use [Patch]

--

David Rutten

david@mcneel.com

Tirol, Austria

Permalink Reply by pwdarden on September 20, 2013 at 1:11pm

hi david, 

thank you for your response.  i have now installed and am using ghowl to read my excel spreadsheet with x,y,z coordinates.  i am just running a test now with 9 points.  the points show up successfully, but now i want to use the [surface from points] component and i have set the u value to number of points + 1 (10) because i've read this is what i should do, but i receive the error message that the u count is not valid for this number of points. 

do you know what i'm doing wrong?  

thank you 

Attachments:

• points.xlsx, 8 KB
• coordinates from spreadsheet.gh, 9 KB

Permalink Reply by pwdarden on September 20, 2013 at 1:26pm

ok, i received help and have a solution!

Permalink Reply by pwdarden on September 20, 2013 at 4:24pm

and i'm stuck again.  i'm working from the definition given in this discussion thread http://www.grasshopper3d.com/group/ghowl/forum/topics/x-y-z-co-ordi... 

however, when i make the surface, it is twisted.  i think this is happening because as the points are computed, the surface morphs.  as an alternative, i'd like to make 5 curves and loft those curves.  the first 7 points = 1st curve, next 7 = 2nd curve, etc. 

does anyone have a suggestion how to do this?

thank you.

Attachments:

• coordinates from spreadsheet.gh, 9 KB
• points_005.xlsx, 9 KB

Permalink Reply by pwdarden on September 20, 2013 at 7:00pm

problem solved.  just needed to put a line component on the end of the point component and loft the lines together.