A question about materials, textures, and their creation

Development Asset Creation
1

Good day UE4 world!

I have hit a bit of a bump.

The tutorials are informative and have helped my understanding of varied aspects of UE4 by leaps and bounds. This has, however, brought me to a bit of a bump (and I expect many more to come).

I don’t quite understand the function of components of materials, and how they effect what I am creating. I can make a texture ‘work’ and I can muddle my way through making others (using the tutorial less and less each time).

So far, I have encountered four components of which I understand each at different levels: Base colours, normals, UVs, and noise.

Could someone explain (in simple terms) what each of these are and how they function in relation to each other? Such as, what does noise do to the texture, how does adding UVs change it, and what is the difference between them?

Here are my guesses based on previous experience working with 2D photo manipulation:
Base colours are textures that we are familiar with (such as, grass, or green, or clouds, or snow).
Normals are negatives, similar to 35mm film before it’s developed into a photograph (where white is black, etc).
UVs are directly responsible for how light is treated on the texture/material (this is as far as I’m able to guess).
Noise adds granular distortion (based on a pre-set value).

I realize that my understanding may be skewed and incorrect, or partially correct… but try as I might, I can’t find a clear description of each component and how they relate to each other (when referring to materials) and how they interact.

I don’t need a detailed document, I can run with simple explanations. I am just missing something, and I don’t know how else to ask the right questions to find the information through an internet search.

Ah, and before I go, one more thing… I’ve heard people talk about 2x2 (or 2 by 2) when referring to creating textures… I presume this has something to do with Mipmaps/scales… it seems to be the “ideal” scaling, but I don’t know exactly what it refers to. Could someone point me in the right direction?

Ta~!

2

For a basic material, all you need is a base_color, metallic , and roughness. With a phyiscally based engine like UE4, you’ll probably want to reference real world values for your base_color, there’s some mentioned in the wiki below. Base_color is the main color of an object, realistic values range from 0.02 for coal, and 0.81 for snow, with a lot of materials falling around .1 to .5. You can use a Constant3Vector in the material editor if you want to change the value and see it update with a quick save. Metallic determines if a material is going to act like a metal, typically you’ll want this a 1 for metal or 0 for non metal, it basically uses the base_color to determine the look of the metal, from gold to copper, chrome or iron, etc. You’ll want to look up those values to use in the base color from PBR refence guids. roughness controls how shinny or dull a material is. 0 is a mirror like polish, very tight highlights, 1 is completely rough.

For metallic and roughness, you just need a black and white texture or a constant1vector to control the values. For basecolor you will use an RGB image or constant3.

The UV map controls how the texture is going to be applied, there’s 2 main approaches, uniquely unwrapping and unwrapping for a tiling texture. UVing is a long topic, but basically all you are doing is making a 3d object flat so you can apply a 2D image to the model. uniquely unwrapping typically has textures that are unique for that model, unwrapping for tiling textures involves setting up the UVs for a more generic and versatile can be used. Tiling normal maps can have worse seams, and have less model specific details, they are normally used for ground textures, wood, rock, patterns, or anything you want to reuse.

UVing has norming to do with lighting

Normals and normal maps have everything to do with lighting.

Normal maps is a huge topic. Each vertex on a model has at least one normal, which controls how a polygon receives light. With a normal map, that value is controlled by the color of a pixel in the normal map combined with the normals on that polygon. You can create a high polygon model and bake or generate a normal map to a low poly model, that’s a unique normal map that will only work for that low poly model (or parts of it). You can also create tiling normal maps that are created in various applications through filters or height maps, that can be tiled onto any mesh that’s setup for one.

3

you mean power of 2 and yes it does have to do with mipmaps, I’m not great at explaining it but basically start with 2 then multiply by 2 and then multiply the result by 2 again and so-on, so 2x2=4 4x2=8 8x2=16 16x2=32…ect, here is a list of the most commonly used power of 2 texture sizes 32/64/128/256/512/1024/2048/4096, you can also mismatch them like having a texture 128x256 and then when it drops in res it will go to 64x128 texture.

4

Err… Did you mean “nothing” ?
If that is the case, the statement is kind of wrong.
UVs are important to lighting in terms of lightmap UVs (and the necessity of creating them manually if the in-situ creation on import doesnt get it right).

5

Thank you for that detailed reply, this will give me a considerable amount to chew on and will help move me in the right direction. I know I have a lot to learn, so every pointer helps.

6

Thank you for clearing up that question ~ this helps as I have a bit of understanding from way back in the day working with Quake 1 texturing. Things have since become considerably more complex, so to have clear and simple answers like yours is very useful. Much appreciated.

7

Your right, I should of said UVs don’t directly effect how a material is lit, until you bake the lighting, but baking lighting and lightmass setting up a scene to be lit is a huge topic on it’s own. If you are just learning how to make materials for the first time, I’d just use one of the example scenes, with decent lighting, and start throwing in your models or preset models, and making materials and textures for them.