"Seamless" fabrics are tiling

[Streetwise]

Is there a trick to get a supposedly seamless material not to tile? These are images from Textures.com. The burlap wall looks horrible. I'm not using any UVW's on the geometry, but scaling the material.

I've always wondered this, but never asked until now.

[leo.surrealismo]

maybe is seamless but the sample is no that big enough

[Streetwise]

maybe is seamless but the sample is no that big enough

I always thought that "seamless" is BECAUSE the sample isn't big enough! If not, what are seamless textures useful for?

[Franx]

Seamless means that the edges of the map blend seamlessly when tiled. If the map is not large enough in relation to the surface you want to texture, tiling will be evident, unless you have a really, really regular texture with no distinctive area popping out within the texture.

[Rens]

Yes, and here's the trick to making tileables work over large areas:

Have several of the same tileable map, but with different UV offsets, then blend them together with different noises (somewhat high contrast so it doesn't just become a soft blurry mess). Works for most stuff.

If you step the UV offsets correctly you can have all the offsets line up correctly, meaning if you have 10 burlap strands visible in the image, then you increment your U for example with 0.1 so that the strands all line up on all of the offsetted images.

Then use a world or local space noise as UV space won't work here (unless you baked world coords into a map channel).

Usually 4-6 offsets work. May need more depending on your scene.

[Streetwise]

Yes, and here's the trick to making tileables work over large areas:

Have several of the same tileable map, but with different UV offsets, then blend them together with different noises (somewhat high contrast so it doesn't just become a soft blurry mess). Works for most stuff.

If you step the UV offsets correctly you can have all the offsets line up correctly, meaning if you have 10 burlap strands visible in the image, then you increment your U for example with 0.1 so that the strands all line up on all of the offsetted images.

Then use a world or local space noise as UV space won't work here (unless you baked world coords into a map channel).

Usually 4-6 offsets work. May need more depending on your scene.

Interesting! So you'd use a VRayBlend material with each instance offset a bit. Hmmm... So where does the noise map come in? Something like this?

[joconnell]

Do it in a composite map, having 6 vray shaders blended causes a lot more calculations!

[flino2004]

go to https://www.poliigon.com/search?category=fabric

get all the maps, specially bump, normal and/or displacement...then work on your diffuse if you need it.
Substance Sources is a good one too.

[Streetwise]

Do it in a composite map, having 6 vray shaders blended causes a lot more calculations!

What type of blend mode do you use for each of the layers then? I'm a bit hazy on how the whole things should be set up. Is it just the U coordinates I want to "step", or the V as well? Also, there's "Crop" and "Place" as options.
Thanks.

[Streetwise]

go to https://www.poliigon.com/search?category=fabric

get all the maps, specially bump, normal and/or displacement...then work on your diffuse if you need it.
Substance Sources is a good one too.

Yes, but what is the sample size? They don't tell you that. So it looks like it would need to tiled too....

[joconnell]

What type of blend mode do you use for each of the layers then? I'm a bit hazy on how the whole things should be set up. Is it just the U coordinates I want to "step", or the V as well? Also, there's "Crop" and "Place" as options.
Thanks.

So you put one copy as the base material, put another copy over the top in normal mode with slightly offset uv coordinates. Since this will block the map underneath you need to use some kind of map in the mask slot of your new layer of the composite map with a very contrasty noise as Rens suggested so you can see through layer 1 to the layer below in places. Keep doing this a few times.

[Morne]

So you put one copy as the base material, put another copy over the top in normal mode with slightly offset uv coordinates. Since this will block the map underneath you need to use some kind of map in the mask slot of your new layer of the composite map with a very contrasty noise as Rens suggested so you can see through layer 1 to the layer below in places. Keep doing this a few times.

Remember to ALSO offset your mask on each copy of the base layer, otherwise you'll only ever see 2 copies no matter how many layers you have

[Streetwise]

Remember to ALSO offset your mask on each copy of the base layer, otherwise you'll only ever see 2 copies no matter how many layers you have

So with the noise map mask offset: Do I use Object XYZ and offset those, or it better to use Explicit Map Channel and offset UV by the same amount as the map?

[Streetwise]

So you put one copy as the base material, put another copy over the top in normal mode with slightly offset uv coordinates. Since this will block the map underneath you need to use some kind of map in the mask slot of your new layer of the composite map with a very contrasty noise as Rens suggested so you can see through layer 1 to the layer below in places. Keep doing this a few times.

Thanks John. So when you say "very contrasty", is that to say quite small and granular? Default is 25. I have it set to "Regular" and "1" for starters.

[Ihno]

So with the noise map mask offset: Do I use Object XYZ and offset those, or it better to use Explicit Map Channel and offset UV by the same amount as the map?

You could also simply use a different phase for the noise. (I.e random seed) What ever gives you a different result.
I think if you offset the noise by the same amount as the texture map you will likely get repeating patterns again.

Wouldn't that whole setup be a cool osl? So one wouldn't need to set this up.
Just an osl with one parameter for the count of levels one parameter for the noise size and one for the noise contrast.