What's the best practice for tiling textures?

[matthiasbasler 2]

Back in the time when Google was keen to have modelers create real building with Google SketchUp, I would create large uniform faces (typically sloped tiled roofs, chimnes or brick walls) by using small generic textures which would tile (repeat) automatically when applied to a face. Often such textures are available are free from texture libraries the web. This worked well, because I could use as many textures as I wanted and Google would later care about generating a single master texture from the (aka texture baking).

To my knowledge Cities Skylines requieres your model to have just one texture ... otherwise the FBX file won't load in the asset editor. There is this SCSH mod for Blender mentiond in another thread which is supposed to take care of texture baking, but unfortunately I have found this Blender extension to not work for me. Thus, so far I do the texture baking manually.

My question to more experienced C:S modellers is: If you need to have all your images in one texture file, how to cope with large faces you would normally use  a tiled texture for?

So far I have only come up with two suboptimal workarounds:

• Make the single texture larger and place an image of the complete roof into it by manually copying and "tiling" the original image as often as needed to cover the whole face
• Only add a single instance of the tiling image into the master texture, then split the face (e.g. the roof) into smaller rectangles and triangles and UV map every one with the same small roof image section. This results in a lot of tedious work, a lot more triangles and a hard-to-maintain 3D geometry, but a smaller master texture.

What's your recommendation?

[Clus 24]

Hello !

Just use the feature that uv - mapping outside of the 0 - 1 area is possible. Use a seamless roof texture f.e. and uv map the whole roof face over it.

That way you won't add any additional geometry to your model and you will have a perfect result without any seams. 

Ronyx69 put a lot of work in to the csl modding guide. Take a look it.

https://cslmodding.info/asset/building/#uv-mapping  <--- that's the uv mapping part for buildings. 

 

I hope that I understood u correctly and that this will help you. 

 

Greetz.

[matthiasbasler 2]

Thanks for your answer.

I tried the approach with the seamless roof texture and tiling during the last days. It works, but is only just practical for several reasons:

Since you have to pack all the images in one single texture, you can only fill a part of this texture with the roof image. So you have to decide whether to tile horizontally or vertically, but you can't have both. Moreover if tiling horizontally (for instance) you have to fill the whole width of the texture with this one image which wastes a lot of space.

What I did as a compromise is to use a 1024x2048px rectangular texture and basically fill the complete upper one third with two rows x two colums of the roof texture image. This way I could utilize the unlimited horizontal tiling and minimize the number of vertical breaks in my roof faces to one. However, using one third of the texture just for one image surely feels like a waste of space.

Looking at the "LOD Mesh" section of the guide you linked I can see a sample models which clearly shows that other modelers choose the other approach, which is to split their faces into rather small sections in order to get a maximum texture re-use and small textures on the expense of many more triangles. The sample buildings in the guide show triangle counts between 4000 and 9000 - my models usually have 500-1000 tris. (One additional reason being that I don't model the windows in 3D.)

Long story short, it seems there's no perfect approach, but I can live with that.