Texel Density 5.12/10.24

Cirmius

Hi

I read that the most common texel density for the games are 5.12 for TPP and 10.24 FPP. I've been using this parameters for a while on 2k/4k textures and I'm not sure if i'm doing it correctly. Am I downscaling the textures actually and should the UVs have 20.48 density on 2k textures etc? I also heard that you should use a half texel for the texture size, like 20.48 for 4k texture.

Eric Chadwick

Which software are you referring to?

Cirmius

Blender, but the thing is not refered to specific software

poopipe

The point of setting a texel density number is to ensure that each pixel is the same size in world space. 

At 5.12 px/cm a 512x512 texture covers 100x100cm
A 1024x1024 covers 200x200cm

Doubling texture size without adjusting UVs doubles texel density

Doubling UV scale without adjusting texture size will halve Tezel density


If you're using a tool to set texel density just put the correct numbers in 

sprunghunt

The goal is to have as high a texel density as you can fit into memory. This involves having a memory budget and a target platform. Questions about any of these things are always difficult to have if you're just making a single asset without any knowledge of the budget of the rest of the scene. 

gnoop

Smaller texel size  doesn't mean  better looking materials .   Smaller it is  fewer actual individual details  you can afford in a texture  and more tricks and time it needs to be looking natural : decals , alternation. macro layers, material  blending  etc.      Especially on walls  etc where you can't hide an ugly and primitive looking   repeating  with lots of 3d geometry.     I think 5 pix /cm is already too small

Alex_J

my approach to this is just go with the eyes first and foremost. If it looks good, it's good. 

I try to keep the math simple - or I just try to avoid math altogether. Like if I am looking at a wall on a building and it looks good, first half of battle is done. It looks good. Next question is can we use less memory and have it still look good? So for that just reduce size of textures. This can be done non-destructively in the game engines. Is there a difference? If not then go with the lower resolution. 

The common resolutions are powers of two so you really don't need to do much math. Just chopping a square into equal sized chunks. If you are going to be re arranging some UV layouts and want to know what the texel density is that works you can do math... or you can just interactively scale the UV shells and look for the resolution you need with your eyes, then copy and paste the texel density value to other shells. 

Obviously this is a quick and dirty way to work and there is value in having a deeper knowledge about what is going on, but I think for the artist just trying to get some work done it's good to have an intuitive, efficient approach and not get sidetracked on details too much. Similar to how when modeling it can become like an OCD thing to make edges all perfectly line up and everything rounded to exact values - but in effect this 1. distracts mind from the important goals of the art and 2. makes a mathematically perfect model which subconsciously creates that "cg" look.

Just opinion of a generalist but I always have to be careful about focusing on wrong areas otherwise my productivity gets killed.

poopipe

One of the primary reasons for setting a texel density is so that when teams make textures, the  features are at a consistent scale.  Eg. you can place a prop made of bricks next to tileable made of bricks and the bricks are similarly scaled.

my team don't refer to materials  by their resolution, instead we describe them by their physical size  .. 2m, 4m etc. 
We do this because it's the only factor that remains consistent -resolution changes by platform, between material channels and increasingly we generate materials by manipulating UVs and blending maps

sprunghunt

gnoop said:

Smaller texel size  doesn't mean  better looking materials .   Smaller it is  fewer actual individual details  you can afford in a texture  and more tricks and time it needs to be looking natural : decals , alternation. macro layers, material  blending  etc.      Especially on walls  etc where you can't hide an ugly and primitive looking   repeating  with lots of 3d geometry.     I think 5 pix /cm is already too small

How well made the texture is has nothing to do with how small the texels are. Well made textures don't look like they're repeating. And repetition of texture features has nothing to do with texel size. 

You can run into a performance issue where if you have too small pixels it causes problems with the fill rate. However in my experience this is extremely rare because you run out of texture memory before you can hit this limit. 

gnoop

sprunghunt said:

 And repetition of texture features has nothing to do with texel size. . 

If you are doing some rocks texture  2x2 meters sized  with  tiny texel size  up to microbes distinguishable   such a thing would never look real  until  you are doing  lots of features  in   geometry.   

    

 Since typical games modelling  involves replacing  geometry with normal mapped  fakes   you can't really  use 2x2 meters textures for a number  of   nature related things.  You perhaps can for  cloth texture or some even looking wall , some natural tiles   but not anything  true complex. 

  Anything having  big cracks  or dry streams  , tree roots . tire tracks   etc .

 Gazillion of  decals  or layers blending wouldn't  hide  2 meters repeating .   Well , gazillion  maybe  but not what you could realistically  do.

 

Kanni3d

^ Might be referring to two different situations or issues.

e.g. two assets with the same texel density - one is using a 512x512 tileable, and the other is using a 2048x2048 tileable. The 512 one will repeat MUCH more, but those will have the same sharpness in texture fidelity.

sprunghunt

gnoop said:

sprunghunt said:

 And repetition of texture features has nothing to do with texel size. . 

If you are doing some rocks texture  2x2 meters sized  with  tiny texel size  up to microbes distinguishable   such a thing would never look real  until  you are doing  lots of features  in   geometry.   

    

 Since typical games modelling  involves replacing  geometry with normal mapped  fakes   you can't really  use 2x2 meters textures for a number  of   nature related things.  You perhaps can for  cloth texture or some even looking wall , some natural tiles   but not anything  true complex. 

  Anything having  big cracks  or dry streams  , tree roots . tire tracks   etc .

 Gazillion of  decals  or layers blending wouldn't  hide  2 meters repeating .   Well , gazillion  maybe  but not what you could realistically  do.

 

You seem to assume that the only way to get a high texel resolution is to increase the tiling of the texture. 

Have you tried not tiling the textures? You can just make a baked rock texture for each rock. If you run out of resolution for a single texture you can have multiple baked textures for a single model. (this is called UDIM in the film industry) 

And yes, if your tiling textures obviously tile, then maybe you need to work on making them not obviously tile. That is purely a texture authoring issue. Don't make textures have detail that is easy to detect as being tiled. Sit down and look at a tiling texture on a flat plane and see what makes you notice that it's tiling - then fix that. 

gnoop

sprunghunt said:

  Don't make textures have detail that is easy to detect as being tiled. Sit down and look at a tiling texture on a flat plane and see what makes you notice that it's tiling - then fix that. 

Yeah,   it's exactly what I meant  when said that many mother  nature materials looks bad  when done that way .  You deprive them from some very distinctive  features  like   any big cracks  for example  or some   wheel tracks  on a road  .       UDIM is out of question for environment texturing   except  distant backgrounds maybe . 

   

What I wanted to say is that  going too small texel size is a trap an artist may fall.  You think that  hi res materials would look cool and great and  end up castrating  all your tiling textures off anything  that make it look natural. 

it's especially obvious when you work with  photogrammetry captured things .  Once you start to weed them out of visibly repeating features  you instantly  notice how they  gradually turns into something opposite to initially real thing.       You have to do it anyway   but smaller texel size is  less of mother nature left.

sprunghunt

gnoop said:

sprunghunt said:

  Don't make textures have detail that is easy to detect as being tiled. Sit down and look at a tiling texture on a flat plane and see what makes you notice that it's tiling - then fix that. 

Yeah,   it's exactly what I meant  when said that many mother  nature materials looks bad  when done that way .  You deprive them from some very distinctive  features  like   any big cracks  for example  or some   wheel tracks  on a road  .       UDIM is out of question for environment texturing   except  distant backgrounds maybe . 

Why do you think it's out of the question? If you have the available texture memory there's absolutely nothing stopping you from making a tree out of 10 uniquely baked textures or a rock out of five different baked textures. 

   

What I wanted to say is that  going too small texel size is a trap an artist may fall.  You think that  hi res materials would look cool and great and  end up castrating  all your tiling textures off anything  that make it look natural. 

it's especially obvious when you work with  photogrammetry captured things .  Once you start to weed them out of visibly repeating features  you instantly  notice how they  gradually turns into something opposite to initially real thing.       You have to do it anyway   but smaller texel size is  less of mother nature left.

Again you're insisting that smaller texel size means more tiling and not bigger texture files. Why do you think this is the only way to do things?  

gnoop

sprunghunt said:

Why do you think it's out of the question?

Why do you think this is the only way to do things?  

Files bigger than 2048x2048 ?    No way.  Sometimes  few 512x4096  maybe  for something long stretched .      UDIMs  for  a few big  assets  and unique macro layer on distant terrains sometimes.   Never for , ground  , walls  .     It's just  from my practice.   

With   unlimited memory budget  there are other ways for sure.      I am talking about typical game  for current hardware.         

sprunghunt

gnoop said:

sprunghunt said:

Why do you think it's out of the question?

Why do you think this is the only way to do things?  

Files bigger than 2048x2048 ?    No way.  Sometimes  few 512x4096  maybe  for something long stretched .      UDIMs  for  a few big  assets  and unique macro layer on distant terrains sometimes.   Never for , ground  , walls  .     It's just  from my practice.   

With   unlimited memory budget  there are other ways for sure.      I am talking about typical game  for current hardware.         

This is the problem I outlined in my original post the amount of texture memory you can use depends heavily on exactly what you're putting in the scene. 

You might not be able to have textures that big because memory is being used somewhere else. But I've shipped at least one game for ps4/xboxone where every single surface had a 4096x4096 on it. 

But if you were making a fighting game you could easily use very large unique textures on every single surface because you have a fixed camera position and didn't have to worry about loading things that you can't see or having huge draw distances etc. 

You don't have to do these things by feel or by guessing. You can draw up a budget based on how much memory you have and how many unique objects you have but there are no hard or fast rules because each game can have completely different needs.