B Spline points correct rotation

vvvv beta question
1

Hi. Congrats on the new site to whoever’s responsible :)

I have a bspline question for y’all

I want to use a bspline to arrange a load of quads along the spline but don’t know how to get the rotation values I need for each quad. I need the quads to rotate correctly along the length of the spline as if forming a piece of ribbon or tape.

I’ve tried using the bspline (3d surface normals) but can’t get any values to come out of the normals pin. How do I do this and once I get these values, how do I use them to rotate the quads?

Can I just feed the normal values into a rotate (vector)?

(patch attached)

Thanks

2

(patch actually attached)

bspline point rotation.v4p (7.1 kB)

3

Ok, just realised that I can only get normals out if the spline is actually a surface, so having a ‘width’ greater than one.

plugging the normals straight into a rotate (vector) doesn’t do the job though.

Any idea how to turn these normal coordinates into correct rotations?

bspline point rotation v2.v4p (7.5 kB)

4

this could be a start:

bspline point rotation v2.v4p (11.3 kB)

5

Thanks!

6

There is a bug somewhere regarding the rotation of the normal vectors. They seem to be flipping axis when the surface goes between concave and convex shapes.

See attached file.

Any ideas?

bspline point rotation v3.v4p (21.0 kB)

7

I think the problem is that the direction of the normal is flipping from one side of the surface to the other.

So I suppose I need a way to always ensure the normals point out of one side of the surface, regardless of the shape of the surface.

Cheers