Advanced Materials Hints

I have been using Blender for a few years now and if there is one thing that I am really stagnating on, it’s my materials knowledge. I can make the basic wood, cloud, image textures, but much beyond that I am really pretty poor and although my modelling continues to grow, it feels like the materials hold me back. I’ve seen what Blender materials can do in the right hands and I want to work towards that.

Would some of the better materials users here at Elysiun be willing to share tips/tricks for learning to create better materials? Thanks.

Sure i’ll give you some tips. You can use some of the varonai (can’t spell it good) textures or noise algorithms or ramp shading to create organic material. And full OSA helps a lot if you want a high nor value for a crusty rough surface.

no? really? you think? maybe he should use colors too! but it’s not very helpful is it?

I suggest looking for tutorials - there are many out there.
I also suggest understending how the blender material system works…
Just looking at stuff and look for farmilier patterns that can be mimiked using blender procedurals and outher features.
Experimenting works for me (though it’s quit hard to do so with complex files).
I don’t like using everything at once - use some features together so every feature of the material could be seen - instead of a mess of textures and reflection and ramps and blah blah blah.
Using UV maps can make an image superb especially when you make layers for bump, spec, disp and so on (this is really good for organics).

Here’s an effect that I have seen used a few time, but I can’t figure out. A material where there is a metal surface that in some places is rusted. In the places where the rust is present, the color of the material is rust colored, as opposed to the rest which is the paint color of the metal. I’m totally stumped on that one.

If someone could offer an example of this that would be great as a start. Thanks again.

That sort of effect was probably acheived by using the Alpha value of an image texture. And some really careful texture-making. If the rust was in places like the edge of the metal, then it was probably UV-mapped with alpha.

For good material practice, you should just draw and color stuff a lot. Try to make everything (colors, shading, lighting, etc.) in the drawings look as realistic as possible. Then you could start drawing textures and UV-mapping them. I know someone that does that… But he’s “professional” (by that I mean he sells his work). Obviously, if drawing’s not your thing, you probably shouldn’t do this. Just a thought.

Here is an excellent tutorial on painting human skin from scratch. It isn’t for Blender, but the same principles still apply:

http://www.3dtotal.com/team/Tutorials/dr_julians_texturing/dr_julians_texturing_01.asp

Also, at the top of that page are a few links to a topic on another forum that talks about procedurals and texturing for photorealism. I suggest you check it out. :smiley:

-Laurifer

Thanks Laurifer, I remember seeing those photorealistic tutorials some time ago and didn’t take the time to read them. They are printing now and I will definately go through them now.

I still think it would be beneficial for some of the more advanced users to share some insights on complex materials in Blender specifically.

as always, look beyond blender. there are tons of tutorials for other packages which apply in a similar way to blender. in many cases, good materials have little to do with the material editor in a certain program, but rather depend on well painted textures. the same applies to rusted metal.

just visit 3dtotal.com, or highend3d.com, or even cgtalk, google, look around… really there’s a lot of stuff, waiting to be picked.

Good small tutes to be found on deviantart

One thing to remember is that a “material” can consist of more than one “texture.”

A better word for “texture” in this case might be signal generator, because each texture is really a function that has inputs and outputs. (Add more than one texture to a material on the default cube, zoom in a little and play around with it.) You can map the texture’s output to lots of different characteristics of the material. You can blend textures’ influences together. You can become very subtle with textures.

I encourage you to really study and explore all of the widgets on the Texture and the Material pages… You’ll quickly go beyond the tutorials when you do so. Just take that default cube and fiddle with it for an hour or two. Or three… four… :smiley: (Much more entertaining than Presidential Debates. :wink: )

And just to get ready, practice your lines: “Holy :o !!”

First you need to understand the difference between materials and textures. Then, second, it’s easier to understand how they relate to one another.

Materials: use two basic factors to come up with a given value; 1)The diffuse and 2) the specular.
Diffuse = diffusion… dic: the angular distribution of radiation by scattering.
In Lambert it uses only reflection, in O/N it uses reflection and roughness.

This defines only how much light is reflected by the material (equally smooth and polished silver and marble will reflect different amounts of light, just as polished silver will reflect more light than tarnished silver will).

Specular = specularity (dictionary is useless but it means) the way in which the reflectivity is scattered. In Cook/Torr and Phong it uses Spec and Hardnes and in Blinn it uses Spec, hard and Refraction

This uses the reflection value to define where and how much the light bounces back and how intense, confined and/or defined the specular quality (zones of high and low reflection) of the reflections are.

See this for better explanations:

http://leigh.cgcommunity.com/tutorials.htm

So, the polished silver will reflect more light than the marble, but their specular values will be more alike than, say, that of hard plastic. Though the plastic may be just as smooth, its mollecules are bigger and so it scatters the light more and therefor has less hardness and less specularity (the area of specularity is wider and more diffuse whereas the silver has sharply defined highlights that shine like the twinkles in a diamond)

Now textures. They simply give color to the material. That is, unless you use their color values (MapTo Tab) to affect the material.
Nor: will affect Difuse and Spec values because it will progressivly wrinkle the surface as you increase the value thus progressivly scattering the light.
Csp, Spec and Hard: will affect the Specular value (Csp actually only the color).
Ref: will affect the Reflection

Obviously RayMir, Alpha and Emit will affect Diffuse and Spec, but their influence is global (across the whole object, or more correctly, across the whole of the material).

So, if a texture is set to Col, then only the Ref settings in the Materials Tab are used, but if it’s set to Col and Ref, then the whitest parts of the texture will reflect more than the Material settings and the blackest parts less. If you set the Ref setting in the Diffuse slider to 0.00, then the reflection values will be taken from the (greyscale) values of the texture… where the whitest parts of the texture are where the material will reflect, where the blackest parts are there will be no reflection, and in-between will reflect something in-between. This same principle applies to all the MapTo options; it allows you to map the diffuse and Spec values to to the material using textures.

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Here’s something I just found out. When using textures, you can fake the effect of a hyper or volemetric texture by stacking planes of the same object very close together and clicking the global button in the texture buttons. Don’t forget to have the alpha all the way to 0, have the texture affect the alpha value and have Z-transparency checked.

Only prob. is that a high res effect with the planes very very close together for a good height is that it takes even a simple stack a good length of time to render. :-?

For rust effects, you can use the “Stencil” setting. It’s hard to describe in words, but is sort of like a mask that allows the textures above(or below?) to be visible ONLY through the stencil areas. Like was said before, set some time aside and experiment. change one parameter at a time and watch what happens…

I used the stencil function in my Penn Station image to make somewhat of a dirt map for the walls and floor. The thing I didn’t like about the stecilling is that you have to use the Blend function to combine the dirt map with the color map of the floor. The thing that was bad about this was that you had to use either Sphere, Diag or Halo. I wish there was a Blend option that covered the whole texture so that the corners of a square object didn’t look cleaner than the center, for instance.

If there is a way around this, I would be interested to know.