Material Definition: Advice, Challenges and Presentation
polycounter lvl 14
How do you recommend improving your ability to define materials? I've seen many people present materials on spheres, boxes, chamfer boxes, cylinders, heavily chamfered cylinders, etc., but to be honest I'm confused by them.
Advice: What is most important to show or achieve in displaying materials by themselves without a model? What should I work on most? What is most lacking in my own work that I need to fix or add? Any thoughts? What does a portfolio need? What should I research more than less?
Challenges: I have been told that my material definition is a weakness to my work so I intend to destroy that weakness. Almost every time I start something new I ask for material definition critique. I am planning on starting a thread soon to simply make materials by themselves without full models to attack that weakness head on. I want to address several types of materials, from plants, dirt, metal, stone, brick, concrete, wallpaper, etc. Admittedly I don't know where to start without doing a model first. What do I go to for reference? What do I make? I'm drawing blanks. Any thoughts?
Presentation: How are they putting these "scenes" together? Are they simply taking these primitives immediately from the modeler as is? Without altering UVs, I've failed to recreate such "scenes". A sphere by nature results in a very stretched texture so I"m confused as to why or how they are being used for this purpose. It looks bad to me. Are people painting directly onto a sphere? That would seem to contradict the point of making a reusable texture. Why would a sphere be an ideal way to display a material? When using chamfered primitives, I'm confused as to get such an even tiling across the bevels? Wouldn't it make more sense to simply use a box or plane? Any thoughts?
This is an example of what I'm talking about and what I'm shooing for:
https://cdn.artstation.rocks/p/assets/images/images/000/519/586/large/erin-mckown-tile-1.jpg?1425420539
Thanks
Advice: What is most important to show or achieve in displaying materials by themselves without a model? What should I work on most? What is most lacking in my own work that I need to fix or add? Any thoughts? What does a portfolio need? What should I research more than less?
Challenges: I have been told that my material definition is a weakness to my work so I intend to destroy that weakness. Almost every time I start something new I ask for material definition critique. I am planning on starting a thread soon to simply make materials by themselves without full models to attack that weakness head on. I want to address several types of materials, from plants, dirt, metal, stone, brick, concrete, wallpaper, etc. Admittedly I don't know where to start without doing a model first. What do I go to for reference? What do I make? I'm drawing blanks. Any thoughts?
Presentation: How are they putting these "scenes" together? Are they simply taking these primitives immediately from the modeler as is? Without altering UVs, I've failed to recreate such "scenes". A sphere by nature results in a very stretched texture so I"m confused as to why or how they are being used for this purpose. It looks bad to me. Are people painting directly onto a sphere? That would seem to contradict the point of making a reusable texture. Why would a sphere be an ideal way to display a material? When using chamfered primitives, I'm confused as to get such an even tiling across the bevels? Wouldn't it make more sense to simply use a box or plane? Any thoughts?
This is an example of what I'm talking about and what I'm shooing for:
https://cdn.artstation.rocks/p/assets/images/images/000/519/586/large/erin-mckown-tile-1.jpg?1425420539
Thanks
Replies
Material definition takes into account the albedo color(s) of the surface, the shapes in the normal map and the model, the gloss/roughness values, and other aspects such as reflection/specular, sub-surface scattering, and tiling detail like cloth texture. Material definition tells you what you're looking at in the same way a dictionary definition of a word tells you its meaning.
To show off materials well, you need two primary things:
- A good shader
- A good lighting setup
A good shader is necessary because without it, you're going to have really weird color behavior and whatever you're presenting isn't going to look right no matter how good your individual textures are. A good lighting setup (such as a 3-point lighting with a good image-based ambient solution) will show off the different properties of your material and it will give an idea of how the material can be used on an object.This: https://www.artstation.com/artwork/cerberus-m-13-raptor
...is a good example of materials that could use better definition. It's hard to get an idea of what materials the gun is made of because there isn't much lighting information to show off things like specular highlights, glossy areas, tiny details like scratches that might reveal underlying layers of different material, etc.
If that gun is supposed to be painted metal, you need to show that. If it's plastic, or composite, or crazy space materials, you need to somehow represent that. One of the best ways to do that is to have varying levels of gloss on different parts so that you can differentiate what different parts do.
In addition to changing things like gloss, you should also invest time in getting a better lighting setup as I mentioned before. Good lighting will highlight problems as well as good areas, and it will make content creation much easier. If the thing you're trying to render is still a work in progress, you should view it under many lighting conditions.
You should show off your skills at making the things you're most interested in making. That said, there are areas of game art that are harder or easier to get into, depending upon your experience level or how specialized they are. If you want to get into environment or prop art, though, you should be putting props and environments in your portfolio.
Research the real world. Look up things like PBR systems and their differences, the best ways to represent materials using a given shader/system, and investigate how professionals do their work.
The real world is your reference library. If you have a camera or smartphone, you can take reference photos anywhere you go.
If there's a material you're trying to replicate, first look online to see how other people have done it. That can give you a leg up. If there aren't PBR value tables and such for what you're trying to do, then go and find similar stuff in the real world and photograph it. Take note of sizes of specular highlights in different lighting, pay attention to how worn certain parts are, look at where dirt collects, pay attention to small details like fingerprints and scratches. It's all in the details.
When people have scenes with primitives to show off materials, they're almost always just taking that simple primitive and slapping the texture on it with very little regard for UVs. Most primitives that you generate in modern software come with pre-made UVs, so you shouldn't have to worry too much about that unless you have some specific UV-related stuff in mind.
If you want to show off tiling materials on a cube, you may have to do some very quick UV mapping to get all the faces to the correct scale, but that shouldn't be an issue.
Take a second look at the spheres used in the Order material presentation images. They very deliberately don't show the poles of the spheres. The point is not to show that it works specifically on a sphere, but rather to show how the material catches the light on curved surfaces.
When using a cube to display materials, you can remap each face to fill the 0-1 UV area completely. This will make any material applied to the cube tile perfectly at the edges of the cube. You would typically UV the cube first, and then bevel/chamfer it so it has round edges.
As far as using non-beveled cubes, the reasoning behind that is pretty clear. Just like when using a sphere, you're doing it so you can see how the material reacts to different lighting across a smooth curved surface. A beveled cube has both flat areas and curved areas, so it's very versatile. It's a much better way to present materials than just slapping them onto a cube.
Although I agree with everything else Swizzle said. That gun in particular would benefit from a re-texture.
When I approach textures, I try to find the exact material I'm trying to recreate. Am I doing a metal on a gun? What kind of metal is it? Does it have a treatment applied (blue'd steel is common on guns). What are the three main parts that make up the material (details specific to that material)? What kind of scuffs appear on that material (think tiny scratches on metal vs. maybe big, larger scuffs on a latex/leather).
@beefaroni: thanks!
One thing I like to do before I start texturing, is identify each surface type (which I break down from the highpoly stage and assign materials to, and bake that out as a color mask). Once you know the sort of material you're going for, it gets a lot easier.
I made this lens for a Marmoset TB2 tutorial, and before I did any real texture work I set up simple spheres. Some of these have textures (pulled from Quixel Megascans data), others are just simply color values in TB2's material editor.
Once I had those base materials reading well on the sphere object, I knew they would look good on proper model, and is was just a matter of layering them together in a logical way. By that I mean, the base material is brass, on top of that is nickel coating, primer, and then a glossy coat of paint, wear naturally occurs on the sharp edges/high use areas, and that's just a matter of masking back to the lower layer.
Part of me is thinking, "am I just making it worse the more I paint it? Should just leave it with a two second substance generator and walk away?"
http://www.polycount.com/forum/showthread.php?p=2289498#post2289498