Feature access to NURBS surface control points weights and knot vectors

[Britton Ward 0]

I'm trying to build a feature that takes in two surfaces of the same parametrization and produces a third surface that is the difference between the two for use in a delta surface image transformation.

 

Does anyone have an example of a feature syntax that shows how to access the control point matrix, knot vectors and weights for a surface?

 

Thanks,

 

Britton Ward

[Jörg 29]

Hi Britton,

 

Please find attached a quick attempt to demonstrate some of the possibilities.

 

Does this help?

 

Cheers

Joerg

nurbsdifference.fdb

[Mr. Claus Abt 14]

Hi Britt,

 

Here is another example which includes two features:

- one that creates a nurbs surface with the real delta of the vertices (which would collapse to 0,0,0 if surfaces are identical)

- one that creates the delta y for constant xz values

 

There is another option for arbitrary surfaces with different number of vertices and degree, if you are really just interested in the delta surface itself. Create a metasurface built on a generic curve that uses the difference between iso parameter curves on the one and on the other surface.

 

Cheers

Claus

 

surfaceDifferences.fdb

[Britton Ward 0]

Claus/Joerg,

Thanks so much for these examples. It certainly helps clarify how to use the interfaces and some of the options available. That will be a big help in the future.  I have spent some time working with the solutions today and I'm thinking that Claus's suggestion of a meta surface generated from the difference between the iso parameters may be the best solution. I'm playing with the curve engine now to create this meta surface and will see how I get on..

 

Thanks,

Britt