From surface with weighted control points to non-weighted

just match a surface to a weighted nurbssurface and do the same with an unweighted one. Count cps and you know the difference. Same for other cad softwares.

VSR was great, but as far as I know they simply sold not enough licenses. The same reason why Surf and Alias are so expensive. People rather believe in sub-d surfaces :confused:

TomTom, when you refer to position matching the initial shapes, it’s the same principle as this?

(Thanks to Lagom for the link to this page…)

yes its pretty much the same approach a bit lazy executed, but with a good eye its enough to just extend them to visually spot it. The intersection basically just determines the point for pulling them back equally spaced. If you would pull them to the intersection you would have a so called “theoretical” edge. Sometimes two surfaces never match or the theoretical edge is very unclean. Then you need to adjust both surface first before blending.

Ok, I have always done this anyway. just seemed like working cleanly. That’s why I didn’t understand the explanation. Just seemed like something for which there would be no other way to do it…

In addition, its also a good idea that in matching direction both base-surface have equal curvature at the point of intersection. Another trick. Apply acceleration when blending with curvature. And always align cps if possible. A nice control polygon often yields a nice surface

I always align control points. in fact, I don’t align them like being on the same horizontal / vertical line. I make sure they are in the same plane. the plane itself can be at angle to the orthogonal grid.

Like this image, again the same hull. Points seem not to be aligned from the side,

However, they are aligned within each plane. The planes themselves also twist and rotate gradually, following the shape.

what do you mean by applying acceleration when blending with curvature? is it some option one can set within the blend tool? Doesn’t each blend (C1 and C2) have acceleration anyway as a default?

Hi Arman – all of the fields in the Weight dialog accept typing.

-Pascal

awesome! I never tried, just because I thought I would not be mathematically possible.

Rebuild will create a non-rational surface (all weights = 1). You will need to select the degree and number of control points in each direction, trading off deviation from the original surface with the number of control points.

Thanks for your input!

I might try. Adding control points, then deleting some afterwards where they aren’t needed.

Hi Arman - use RemoveControlPoint rather than deleting the points so maintain good (uniform) surface structure.

-Pascal

understood, that’s what I meant to say. Sorry for not using proper terms. Some of the tools I don’t even know what their name is, just where they can be found and what they do. it’s just an icon in the tool bar to me.

Or use RemoveKnot which will minimize changes to the shape but shift the location of the remaining control points.

:ok_hand: