Idea for rebuild a surface (nbrU, nbrV)

Replies to This Discussion

Permalink Reply by David Rutten on January 27, 2011 at 8:13am

Hi RG,

 

what are nbrU and nbrV? Changing the Domain of the surface does not equal rebuilding it.

 

If you want to change the domains of a surface, you'll need to assign these new domains like so:

 

srf.SetDomain(0, New Interval(0, 10))    

srf.SetDomain(1, New Interval(0, 10))

 

--

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by RG on January 27, 2011 at 8:57am

Verry interesting, what is the difference between rebulding and change the domain?

Thanks:)

Permalink Reply by David Rutten on January 27, 2011 at 12:37pm

Changing the domain does not in any way change the surface shape. It maintains the number of control-points, the weight of control-points, knot ratios and degrees. Rebuilding creates an entirely new surface with potentially different degrees, control-point-count, parameterization etc. etc.

 

The easiest way to imagine a Rebuild is to divide the surface into a grid of points, then create a new surface with the control-points at these locations. It is quite a bit smarter than that, but that is the basic idea.

 

--

David Rutten

david@mcneel.com

Poprad, Slovakia

 

Permalink Reply by David Rutten on January 27, 2011 at 12:38pm

Incidentally, both operations are available as standard Rhino commands, so you can see the difference quite easily. Compare the outputs of the _Rebuild and the _Reparameterize commands. You can use the _What and the _List commands to examine the data structure of any given surface.

 

--

David Rutten

david@mcneel.com

Poprad, Slovakia