Question regarding tiling textures/texel density

jordank95

I have determined that I want my game to have 5.12 pixels per unit (or 512 per meter). Now, with Maya, I can select all my UV shells in my entire modular kit and have them all scaled to 5.12 texel density for whatever size map I decide to use. Great, now they are all the same texel density. But my question is, how do you determine what size texture map to use? Are all tiling textures usually about 2k? If a tiling texture is really anything less than 1k, it starts to get blurry. What if I have some props I want to share the same texture map...how do I determine what size map I should be using?

Obscura

"texel density" and texture resolution is pretty much the same thing, at least in this context. One determines the another. When you set your modular mesh uvs to use 512p/m, it means you assume that uv space 0-1 will be filled up with a 512 texture, and this 512 or whatever resolution texture will fill up space equal to 1m on the mesh. So parts bigger than 1m will hang outside of 0-1 space. This works with tiling textures. If you apply a 2048 texture to the same unwrap, you get density of 2k/meter.

Maintaining consistent texel density without wasting uv space with a mesh that requires a unique unwrap, is more complicated. But thats where non square textures can come in.

Alex_J

Use the minimum amount that achieves the aesthetic you need. 

A garbage can in a sprawling city... maybe that is ok to be a bit blurry. 

A sports car that the player is driving... that should probably use a high enough texture resolution that it looks as crisp and detailed as you need it to. 

If not sure, just go with a larger size, and reduce it later if necessary. 

jordank95

Obscura said:

"texel density" and texture resolution is pretty much the same thing, at least in this context. One determines the another. When you set your modular mesh uvs to use 512p/m, it means you assume that uv space 0-1 will be filled up with a 512 texture, and this 512 or whatever resolution texture will fill up space equal to 1m on the mesh. So parts bigger than 1m will hang outside of 0-1 space. This works with tiling textures. If you apply a 2048 texture to the same unwrap, you get density of 2k/meter.

Maintaining consistent texel density without wasting uv space with a mesh that requires a unique unwrap, is more complicated. But thats where non square textures can come in.

So if I have a modular asset thats 2x2 meters, and my texel density is 512 per meter, I should use a 1024 texture map on that modular asset?

Should I basically know the size of each of my assets to determine what size texture map I should be using? For example, if I have a bicycle, should I roughly measure the size of the bike and determine the texture map size based on that?

Obscura

If its a 2x2m plane, then yes. And yes. Well. Kinda. Dimensions isn't just 2 axis, a bike would have wrapping shapes, cylinders. Imagine you unfold them without changing the size or proportions. It will fill up some space, and compare texel density to that. So a 1m box, depending on the unwrap can end up being 4 meters if you unwrap it as a cross or T shape. If you separate all faces, you could pack them better so overall size would end up being ~3m. Hope this makes sense. Like whats the size of it when its unwrapped.

jordank95

Obscura said:

If its a 2x2m plane, then yes. And yes. Well. Kinda. Dimensions isn't just 2 axis, a bike would have wrapping shapes, cylinders. Imagine you unfold them without changing the size or proportions. It will fill up some space, and compare texel density to that. So a 1m box, depending on the unwrap can end up being 4 meters if you unwrap it as a cross or T shape. If you separate all faces, you could pack them better so overall size would end up being ~3m. Hope this makes sense. Like whats the size of it when its unwrapped.

Hmm. Sort of. So what would be a good general workflow if I have my whole environment blocked out and everything is pretty much ready to be UVd and I know that I want 512pix per meter? 

Im just still really confused as to what size texture I should be using for tiling textures. If I have a 512 tiling texture, its really low res and does not look good. But if I have a 2k tiling texture, this looks good for my assets that I applied the 5.12 texel density to. Im just confused as to how to tell and know what texture sizes to use for tiling textures.

If you have any pointers on the breakdown of steps to this process, that would be great. I learn better by breaking things down in steps.

poopipe

Texel density is tied to texture size.  

If you unwrap an object at 5 px/cm on a 1k map and apply a 2k map you end up with 10 px/cm.

The best thing to do is unwrap an object, normalise the scale of the uvs, pick a texture size, set the density by either using a script or working it out in your head and see whether they fit or not.  
If not,  change the size until they do

CarlCraft

This is the best article I've found explaining texel density
https://80.lv/articles/textel-density-tutorial/

When working in Maya there is a tool that estimates your texel density. Selec your UVs, set px/cm, hit scale and Maya will give you as close to that texel density as it can. It's a good starting point for your UV sizes.

jordank95

CarlCraft said:

This is the best article I've found explaining texel density
https://80.lv/articles/textel-density-tutorial/

When working in Maya there is a tool that estimates your texel density. Selec your UVs, set px/cm, hit scale and Maya will give you as close to that texel density as it can. It's a good starting point for your UV sizes.

Thanks Carl, I’ve seen this article and it’s quite helpful. Though I’m still not understanding one portion of it, which is how do you know what size texture map to use? Maybe I’m just not understanding here. But what makes someone use a 1k over a 2k tiling texture map? and also if I unwrap a bicycle for example, and choose my texel density, then have Maya scale my UVs, if it’s anything under 2k the UVs are very outside of the 0-1. I HAVE to scale them down to fit. Then my texel density of off. Just still confused as to the proper steps how to do this. 

poopipe

If it won't fit at the desired density then you know you have to use a bigger map or get creative with your UVs

Thats how we know 

jordank95

poopipe said:

If it won't fit at the desired density then you know you have to use a bigger map or get creative with your UVs

Thats how we know 

After a couple days of doing this, it finally sunk in. I now understand all of this! Thanks!