Surface from end line points

Grasshopper
1

I’m trying to make a surface from this intersection points the points does not match with the initial surface because I had to rebuild some curves so what could be the correct way to make a surface from this points to get match with the new rebuilded curves.

I tried to search in forum but with all mixed topics was a little bit complicated search.
surfa fp.gh (39.1 KB)
surface fp

2

How close does the surface need to match the points?

In regular Rhino I would use Patch. Create a new surface using pnly bounding curves, probably using Loft. RebuildUV to add a sufficient number of control points between the edges. Patch with points as the input,the surface just created as the start surface, and edges fixed.

3

totally close, I don’t understand what you are trying to wrote :confused:

4

There’s essentially four ways to ‘fit’ a surface to a set of points.

  • The points are in a rectangular array and you can just place the surface-control-points on top of them. This tends to result in a smooth surface, however it will not actually intersect any of the original points. The surface will merely approach them.
  • The points are in a rectangular array and you interpolate them. This can result in weird bulges or stretched surface regions, but at least you’re guaranteed the surface intersects all the points exactly.
  • If the points are not in a rectangular array then the surface needs to be fitted some other way. For example by using Patch (as @davidcockey mentioned). Patch tends to result in smooth surfaces, and you have control over the accuracy, but there is no guarantee that the surface will in fact intersect all the points.
  • You can always try to do this in stages. For example you could first try to generate curves from your points and then loft those curves. This approach can be complicated and very case-specific.

Your points aren’t now organised in a good grid, but it looks like they could be if some of the lists are cycled:

grid
grid.jpg1159×823 332 KB

1 Like
5

This approach uses Curve interpolation and then lofting the result. I had to manually fix the point ordering.

interploft
interploft1254×797 271 KB

surfa fp.gh (47.8 KB)

6

@DavidRutten, From the ways you listed above to fit a surface through a set of points (intersecting those), do you know which one is used in the command SrfPtGrid from Rhino?

Thanks!

7

#2. It interpolates the points.

8

Well, I am trying to proceed this way (#2) to obtain a surface that matches exactly a SrfPtGrid, but unfortunately I can´t find an interpolation that fits the edge curve. Is there any other way to do so? My goal is to implement a component that gives in GH the same output that Rhino would give with SrfPtGrid.

SrfPtGrid and interpolated curves
SrfPtGrid and interpolated curves1197×702 103 KB

SrfPtGrid and interpolated curves.3dm (73.9 KB)

9

how do you do that ? sorry I think is a very noob question.

10

I used the Shift List component with a custom crafted list of offsets (the numbers typed into the yellow panel).

1 Like
11

thank you master I did notice that list I assumed that were the custom list but I can´t figure out how the order corresponds to the correct points but actually I’m noob and I just involving in path mapper and data structure so maybe with more knowledge I will be able to deduce it.