Bitmaps are square and meshes aren't!?

Support Materials and Textures
1

Hey people!

The Confusion

One thing has been bothering me a whole lot and it’s this. When I make bitmaps in Substance designer (which means they’re all tileable), they’re 1:1 or square and even though I can change the ratio and give them any other rectangular form what puzzles me the most is that no mesh is like that. The texture won’t tile if the UVs are out of the 1:1 ratio right? The seams would be visible as was the case with me when I tried unwrapping when I exported a bitmap from Designer.

I watched Blender Guru’s UV unwrapping and I get it, I understand the concept and I did the same. UV islands are present and then he just jumps into Texturing without adhering to the fact that these UV’s aren’t perfect square even though the maps are! And goes on without talking about it either. I understand the fact that textures don’t have to tile where there are great angle differences in edges.

But, having multiple UV islands and none of them fitting the 1:1 size of outline of the bitmap I’m loading, how will they tile? I think that’s such a lack of control of how it’s appearing on my mesh.

Maybe I’m looking at it wrong. I really hope I am.

So, I’m super confused :smiley: Please help me with this!

2

UV maps don’t necessarily have to just be the source for the texture coordinates, they can also be the target. They’re used for painting textures directly on the model and the pixel information land on their corresponding coordinates on a new image, or used for baking which gathers material assigned texture information or other source and puts them on an image.

An area can be isolated on a model to only show a portion of a image texture by using different materials, where the UV map covers that and a larger area. Or the other way around by using one material but using multiple UV maps. A bit like matching wood pattern on two halves and then cutting the shape of the part out of it.

Having an image with just one black line on it, there’s no way to have that line be continuous over an area if that area is cut to two UV islands. You would have to use the image to paint on the model where they’re side by side, or by using coordinates that cover both and then split them on the two. Same thing.