Ribbons and spline-following uv texturing

General TouchDesigner Discussion
1

Hi guys,

I can’t wrap my head around how I can do that, so posting here, perhaps it will help someone too.

If needed, I can write to support too.

So, I have a loooooot of ribbon-like arbitrary 2D shapes (think 60) used for mapping on the real structure with those shapes.

The idea is to grow these shapes (generatively I must say) so the tangent would be always (sort of) perpendicular. Basically, it should follow the shape.

And because there are 60 of those, I was set to do the following:

  1. I have a bunch of spline from illustrator and I’m using Loft in C4D to create surfaces with nice point distribution.

  2. In TD I’m parametrizind UV so it would use just 1 pixel (then stretched to the whole cross-section).

  3. I’m generating my UV map 60px x 1000px and with GLSL multi component moving those line in real-time.

  4. Applying this texture to the model. Rendering just once and Voilà!

I couldn’t have imagined it would be such a pain to get those UV correct. For some reason, TD just doesn’t want to paramtrize those ribbons (via Basis)-I’ve tried everything I could think of.

Is there a better way to do it? What would be your solution?

I thought about 1 myself, but it’s very consuming:

  1. Basically, I need to create center splines and use the LineThick to create coverin ribbon which is already parametrized in row and columnes.

  2. I render fully colored original geometry and use my newly created matte geometry with the same UV trick I wanted to use previously to reveal rendered composition.

The problem with this method is that the shapes are tightly packed and very intricate and with LineThick there’s no control about ebb&flow of the shape.

I tried rails, polypatch for my splines, just doesn’t wanna cooperate :frowning:

It just seems that there must be a better way to do it directly on the original geometry.

What do you think?

Please, help :slight_smile:

Best
sH

2

If I understand your project correctly, you might have better luck with a Limit SOP generating lofted geometry from a spline (fed in as CHOP channels, e.g. tx, ty, tz, radius). Then on the output page be sure to enable “Apply texture” and scale the generated UV map as needed.

derivative.ca/wiki088/index … =Limit_SOP

3

Hi CutMod,

Thanks for the reply. I’m actually unmounting this project already, but thanks for the idea. It’s funny, I’ve never thought about Limit Sop. I’ll try it out, it’s always fun to learn.

The thing is, I tried it every possible way, but the ribbons were just not regular enough, so I did all the lofting and divisions in the 3d package to make sure the ribbons behaved the way I wanted them to. I think this is the best way even though it takes whole lot of time, I even needed to develop a special script to number correctly polygons so TD would use the correct order.

So, to anyone working with ribbons, it all depends on the regularity. If it’s an artwork, like in my case, there’s no way to do it in automatic way unless you have an AI.

Actually, thinking about it, I used 2 ways - the first one I’ve just described (the texture is applied directly to the geometry). But when the ribbons had too many twists and irregularities, I used the false geometry (I think it was tubes) for the uv texture and the original geometry alpha as matte and it worked out beautifully!

Best
sH