A subdivision surface

Hello all，We know that we can calculate a subdivision surface form a delaunay surface by weaverbird，but the subdivision surface don't fit the control points,Can we make a surface that come across the control points?

Thank you a lot!

Replies to This Discussion

Permalink Reply by zhouningyi on September 2, 2012 at 9:32am

Permalink Reply by Vicente Soler on September 2, 2012 at 10:38am

Change the S input to 0 or Fixed.

Permalink Reply by zhouningyi on September 2, 2012 at 10:50am

Thank you

The S input in picture above is 0，But only boundary points are fixed...

Permalink Reply by Vicente Soler on September 2, 2012 at 10:52am

Aren't the boundary points what you are trying to keep fixed?

Permalink Reply by zhouningyi on September 2, 2012 at 11:13am

I want to fix all the points in the input mesh（a delaunay mesh） ..

Permalink Reply by Vicente Soler on September 2, 2012 at 11:23am

If you fix all the original mesh vertices, nothing will smooth out using WB subdiv components. You'll to use another method. For example:

Use the split polygon component to create a subdivided mesh without modifying the original shape, then use Kangaroo to smooth out the mesh by using the original mesh vertices as anchor points and the subdivided mesh edges as springs with 0 rest length.

Permalink Reply by zhouningyi on September 2, 2012 at 11:56am

Thank you Vicente Soler very much！ I will have a try，Hopethis method can create a smooth mesh!

Is there any quick solutions？I think maybe this is a very general interpolation problem？

Permalink Reply by Giulio Piacentino on September 4, 2012 at 4:23am

Yes, this is definitely a general algorithm difference (approximation vs interpolation). I am have been on and off busy coding the Butterfly Subdivision scheme, which keeps the previous points and thus would always pass through the previous Delaunay points in this case.

Permalink Reply by Vicente Soler on September 2, 2012 at 4:43pm

If you've got an unordered set of data points (in this case height data), the best way to create smooth interpolation between them is with natural neighbor interpolation. There is no direct component for this but it might be possible to do using a combination of components. I'm using the phone right now, when I get access to a PC I'll try to put together a definition.

Permalink Reply by zhouningyi on September 2, 2012 at 9:47pm

okay thank you very very much！

Permalink Reply by Vicente Soler on September 3, 2012 at 4:52am

Here you have:

Left - delaunay

right - natural neighbor using the delaunay mesh subdivided twice.

Not the most elegant definition but works without scripting components. It's slow since it's doing region intersection and area calculation. You could speed it up by instead of region intersection, placing random points inside the voronoi cells and calculating what perecentage falls in each of the neighboring cells, you could then toggle speed/quality by increasing or descreasing the number of points.

Permalink Reply by zhouningyi on September 4, 2012 at 11:16am

Thank you very much，very nice of you

Using voronoi to caculate the weight of points is difficult to understand，Spent a lot of time to find the reason...