# Are Rhino curves vectors?

Forgive me if this is a … stupid question but are Rhino curves, lines etc. “vectors”? I know that surfaces and solids are nurbs, but are Rhino curves vectors?

Thank you.

absolutely vectors

Rhino curves are NURBS. Rhino surfaces are interpolations of NURBS curves in two directions.

When people speak of “vector” they are usually referring to the difference between vector and raster data structures; vector type graphics meaning that the curves are determined by some sort of mathematical definition as in NURBS or B-Splines, raster graphics meaning pixel based (images). In view of the above, Rhino can be considered to be a “vector” based program. Photoshop would be a typical “raster” based program. Something like Illustrator can do both.

In the very literal sense Rhino curves are not “vectors” as a vector is simply a mathematical structure indicating magnitude and direction.

–Mitch

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hi Mitch
can you help me in this post?

Not much I’m afraid. As far as Grasshopper is concerned, you might want to post this on the Grasshopper forum, there are a lot of computerheads who hang out there, they might be able to give you more info…

Best regards, --Mitch

thank you Mitch.I have also post help on there,I’m waiting for some reply.

Thank you @Mitch. I wonder if I can extend the question to what is the difference between Rhino and subd modeling program. Are they raster?

Is Sketchup a subd modeling program?

Hi Allyson - ‘raster’ does not really apply, as far as I know, to 3d modeling , but it is more analogous to meshes than anything else I suppose, when comparing to ‘NURBS’. A key thing about raster (pixels) is that it has a finite amount of info at a pixel - it is one color, period - meshes are somewhat like that in that you only have accurate information at the vertices. A vector curve or a NURBS curve or surface, on the other hand, has accurate information anyplace on the curve. Think of a sphere - as a mesh it might have, let’s say 256 vertices - you could get an accurate 3d location of any of the vertices, but between vertices you’re out of luck - the best you can do is a linear interpolation between two adjacent vertices. On a sphere defined as a surface - either NURBS or some other exact definition, you can ask about position (and other) info anyplace on the sphere and get accurate results- the entire surface is defined, not just some subset of points on the surface. SubD makes, you might say, a better guess at smoothly interpolating mesh information than a linear interpolation between points. Sub D are less constrained in certain ways than surface structures - they can branch in multiple directions like a mesh,and have more flexible topology than surfaces. Surfaces are constrained to rectangular structure, so in a way it makes it trickier to build complex but smooth ‘organic’ shapes from these than with Sub D.

SketchUp is a mesh modeler.

-Pascal

Thank you, Pascal. I really appreciate the explanation.