I want to find a procedural material/texture for white polka-dots on solid colored fabric … for use with dresses and various props. I did find one video that seemed to discuss it but found it extremely difficult to follow. What would be ideal is an actual .blend file for the current version of Blender, so that I can de-construct it myself and see how it works.
Anyone got one handy?
(It doesn’t have to be exactly that … just enough to show the principles of how to do this sort of thing.)
Voronoi texture with zero Randomness plugged into ColorRamp with “constant” interpolation (or MapRange with “Stepped Linear” interpolation and “1” step).
Should give you an array of round shapes that can be used as a mask.
Is that what you need?
That will be very close, yes.
Try this:
And the file: polka-dots.blend (720.6 KB)
You can tweak various settings like the “less then” threshold, which removes unnecessary values to get a clean look.
Excellent – thanks, Blutag. That’s a little more intricate than what I had first come up with but it looks very nice indeed. Just what I needed.
I’m a bit puzzled by one thing – the texture seems to be coming out as stripes.
Now, the the object is the canopy of an umbrella, built using the techniques described in my thread on “low-poly umbrella” over in Modeling. It consists of a single vector, to which the Screw modifier has been applied to make an eight-sided shape. I’ve been fiddling with the Texture Coordinates input node but I’m still seeing stripes coming out of the Voroni node. Is this a consequence of the fact that the canopy is topologically-speaking “a vector?”
I think coordinates are generated at the end of the modifier stack so it shouldn’t be a problem. Try applying rotation & scale, that’s usually the main culprit with deformed materials.
Good idea. I know that there are coords because I see pretty stripes (which will do in a pinch). The vector is rotated slightly now. I’m just wondering why it isn’t dots. 
Anyhow, maybe it’ll be a striped umbrella, and that’s fine too.
Here is one that generates a length output which can be “greater than”'ed for hexagonal patterned polka dots over a 2D coordinate system (like UVs):
Thanks for that! (Where’s a good one-liner mathematical formula when you need one?) 
Heere’s a simplified version of “polka dots” applied to my umbrella, a cube, and a filled circle. (The latter two UV-unwrapped.) The umbrella proved to be interesting because it consists of a “screwed” vector – you can’t UV-map it, and the Voroni texture shows up properly only if it is slightly-random and at a very small scale with “object” coordinates. (Not shown here – what’s her is to make the circle look right.) I couldn’t find any “Texture Coordinates” option to make the umbrella-top look like the circle does. Nonetheless, I was able to decorate my little girl’s umbrella. Thanks for the help!
I think if you set your Voronoi to 2D it will project the texture on Z-axis…
You won’t have those concentric circles on the umbrella this way
Good call. I thought I’d fiddle with “2D” already but must have missed it. Indeed, this did even-out the pattern, eliminate the spiral pattern and remove the need for “random > 0.0.”
Coming up with lots of procedural possibilities now for decorating that umbrella. It might or might not wind up with polka-dots.
FYI, here’s the blend-file showing the umbrella, cube and circle. The umbrella is a simplified version of the one described in the video tutorial linked in the “Low-Poly Umbrella” thread in Modeling – omitting niceities like drivers and such which I didn’t need to bother with for my project. Nor did I need for it to actually look much like “fabric.” Furl the umbrella by rotating the empty at the top. (The “2D/3D” setting does make a difference between a flat-umbrella or flat-circle and a 3D cube, but that’s obvious enough.)
Umbrella.blend (922.1 KB)
