Weights for curve and surface design - how common?

How common is the explicit use of weights to modify the shapes of NURBS curves and surfaces? For example increasing a weight to increase curvature of part of a curve. My impression is editing weights is common in illustration and graphic arts but not common in other uses of CAD.

The most dommon use of weights with NURBS is to create exact conical curves such as circular arcs, parabolas, etc. I’m asking about a different use of weights with users modifying weights to change the shape of curves and surfaces.

This question is due to curiosity, nothting else.

Hi David - that is my (under-informed) impression as well.


Hi @davidcockey

all you said is also my impression .
from my experience in rhino … I have never found significant weight utility. for successful freeform surfacing.
I always avoid the use of rational geometry …

I think their usefulness is to create more complex shapes without needing to increase the number of control points. their only handicap is that these surfaces are not compatible with the match command

The main problem with using them, I in my experience, for freeform surface design is that they make your surfaces behave unpredictably, you can’t “tell” that a point has its weight set some different way just by looking at it, you’re just going to notice that something acts weird, and the weights only mean anything relative to surrounding points. More points where you want sharper detail, that you can see.

Yes exactly. the match command messes up the checkpoints. and reposition them badly …