Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member

Making sense of mental ray shaders

From: Creating Textures and Shaders in Maya

Video: Making sense of mental ray shaders

In this movie, we are going to talk about making sense of some of the mental ray shaders that come with Maya. Some of these shaders can be quite complex and especially when you are first learning mental ray they can be difficult to use. They are good for simulating a variety of materials but they can give you a lot of headaches. So, my goal for this movie is to help you eliminate some of those headaches. I am going to talk about how these shaders work and also some alternatives that can make your life a bit easier. In this rendering here I have three teapots and each one has a different mental ray shader apply to it.

Making sense of mental ray shaders

In this movie, we are going to talk about making sense of some of the mental ray shaders that come with Maya. Some of these shaders can be quite complex and especially when you are first learning mental ray they can be difficult to use. They are good for simulating a variety of materials but they can give you a lot of headaches. So, my goal for this movie is to help you eliminate some of those headaches. I am going to talk about how these shaders work and also some alternatives that can make your life a bit easier. In this rendering here I have three teapots and each one has a different mental ray shader apply to it.

Up here, in the far left I have a DGS shader applied to this teapot. That's the Diffuse, Glossy, Specular shader. In the center, I have the dielectric shader applied and this is meant to simulate glass or liquid. You see it has very nice refractive qualities to it. Then down here on the lower right I have an MIB network applied to this shader. The MIB stands for Mental Images Base shader. So, let's take a look at what's going on in this scene. I am going to store this image in the Render View and minimize the Render View.

I am going to start with the DGS shader. So, I am going to select this object, open the Hypershade by choosing Windows > Rendering Editors > Hypershade. In the work area of the Hypershade, I am going to right-click and choose Graph Materials on Selected Objects. And here we see the dgs_material1. So, I'll select this material and open up the Attribute Editor. Let's just take a quick look at it. The material here it doesn't have too many settings.

The main settings are the Diffuse, Glossy and Specular channel and then below this we have additional settings that allow you to adjust the Transparency, Index of Refraction as well as the quality of the Specular highlight. Now, the Diffuse channel is fairly straightforward. This is where you determine the color of the objects. So, if I click on there. I can choose a color so I'll just choose green for this. But,what's confusing where the shaders we have a Glossy channel and a Specular channel and both of these have different ways of controlling the reflective qualities of the material and it's slightly redundant.

So, for example if I set these both to black the Glossy channel controls the specular highlight, the color of it and it's overall brightness, but it also controls some of the reflective qualities of the shaders as well. So, if I hide the lower two parts, I am just going to select them and press Ctrl+H to hide them and zoom in and I'll do a quick rendering. You can see that we have reflection and we also have specular highlight.

But if I select this material and turn the Glossy to black and turn up the Specular aspect of it and then do another render, now we see a nice reflection but no specular highlight. So, where this gets confusing is that the Glossy channel controls both the specular highlight and the reflectivity and the Specular channel controls just reflectivity. So, which one do you use? How do you get the proper reflection out of your material? It gets a little bit confusing and can spend a lot of time doodling with this and not get way the results you want.

On top of this you have a Shiny setting which controls the blurriness of the reflections. So, it's an okay material but I don't use it very much in my own work because I find it very non-intuitive. So, I am going to select the dielectric_pot here in the outliner and choose Display > Show Selection and I'll select the dgs_pot and do Ctrl+H to hide it. Let's take a look at this material. I am going to do another quick render here. To the most pot of this material does a good job of simulating glass but you'll notice that the shadow cast by the object is opaque.

This can drive you a little bit crazy because you have to jump through a number of hoops in order to get a transparent shadow going that's effective. So, if I select the dielectric_pot object in the outliner, right-click in the Hypershade, and choose Graph Materials on Selected Objects. I can select the material and open up the attribute editor. There are several channels to control the color of the object. You have Color and Outside Object and Outside Color. You also have two settings for Index of Refraction and the idea is that material is meant to accurately simulate light as it passage through multiple surfaces.

So, for example the Index of Refraction here would control the index of refraction for the glass. Outside Index of Refraction would control say the index of refraction of the air. So, if I set this to 1 that will be the index of refraction for the air. Then the Phong Coefficient controls the specular highlight. What makes this material particularly difficult to use is in order to get that transparent shadow you have to either create some workflow that involves render passes or render layers. So, one render layer would have the dielectric material and no shadows cast and another render layer would have an object that has a transparent material applied but the object is hidden and then you could composite the shadow.

You can see it starts to get more and more complicated. The other alternative would be to select the dielectric_material shading group node and connects the dielectric_ material Photonic node to the photon shaders slide down here in the shading group node. Again, very complicated and on top of this you have to start messing with caustics. It becomes a pain in the neck. So, again not a material that I use very often. Then finally I'm going to display the MIB_pot.

I'll select it, right-click in the Hypershade, and choose Graph Materials on selection. You can see for this material this shader has actually created of a network of two other materials. We have the mib cook_torrance which determines the diffuse quality as well as the specular highlight but does not have any settings for the reflection. Reflection is controlled by the mib_glossy_reflection node. So, in order to set this up I need to connect the mib cook_torrance to the Base material of the glossy_reflection_node.

You'll notice if I select in the Hypershade under Materials that there are a number of MIB nodes. We have a Blinn, Cook-Torrance, Lambert, Phong, Ward and so on and so forth. All of these shaders control the diffuse quality and the specular highlight but they need to be connected to an mib_ glossy_reflection node or to indicate a transparent material you need to connect it to a mib_glossy_refraction node. Then to get the look that you want you need to basically adjust the settings on both nodes.

So, there's a lot of jumping back and forth and adjusting these settings until you get what you want. Again, it can be a kind of a headache especially if you are just hasn't come up with something fairly simple. So, what is the alternative? Well, these shaders are from an older version of mental ray that has been integrated into Maya. The reason they still exist is largely to provide legacy support for people using older shaders or older workflows. There is an alternative to using these shaders that can make your life a lot easier. So, I am going to show these objects again and I am going to set Diffuse back to dark gray color for the dgs node.

I am going to select the mia_pot 1, 2 and 3 objects in the Outliner and I'm going to choose Display Show Selection. So, what I've done in this scene is I've created three alternate pots here in the back behind these in the front. These pots all have different variations of the mia_material applied to them. So, again if I open up the Hypershade the mia_materials found under mental ray > Materials and it's this material right here, mia_material.

I use the mia_x_passes material most of the time. This material is an awful lot of settings but at the same time these settings allow you to simulate just pretty much anything you want to without the headaches of the other more complex shader networks. So, if I do a render here you'll see that what I've done is I've quickly used mia_materials to imitate the same look that I created with the other mental ray shaders. I'm just trying to drive home the point here that for the most part you don't need to use the DGS, the Dielectric or the MIB shading networks to create good-looking materials.

You can skip those altogether and just start working with the mia_materials. You can see like for instance this transparent glass shader that I've created using mia_material. It looks extremely as similar to the Dielectric shader. I think it's a bit more physically accurate we don't have these over bright reds here. This to me looks more realistic than this does and you'll also notice nice transparent shadow has already been created and it's part of the material. I don't need to jump through any extra hoops to create a transparent shadow for this shader.

Diffuse glossy shader, I've imitated very quickly using an mia_network and same with the MIB-based network. Again, I think this shader to me looks more realistic than what I've created with the MIB Base material. So, the bottom line as an academic exercise it's a good idea to learn about how these materials work. But if you really want to get some work done and you what to create a good-looking render which I'm assuming is your actual goal, then skip these shaders, go straight to the mia_material and master that maternal.

You'll be able to simulate pretty much anything you can think of. mia_ stands for Mental Images Architectural shading node and the purpose behind it is for simulating hard surface objects. But I've actually used it to simulate a wide variety of shading types. I've used it for insects. I've used it for translucent plastic. I've used it for special effects for things like you know scanning electron, microscope shaders. Pretty much anything you can think of with the exception maybe of human skin the mia_material is perfect for it.

Show transcript

This video is part of

Image for Creating Textures and Shaders in Maya
Creating Textures and Shaders in Maya

37 video lessons · 8017 viewers

Eric Keller
Author

 
Expand all | Collapse all
  1. 2m 19s
    1. Welcome
      1m 6s
    2. Using the exercise files
      1m 13s
  2. 17m 49s
    1. Explaining diffuse reflections
      2m 39s
    2. Defining glossy and blurred reflections
      2m 32s
    3. Looking at refraction
      4m 20s
    4. Describing the Fresnel effect
      1m 56s
    5. Understanding anisotropy
      1m 10s
    6. Identifying ambient and reflection occlusion
      1m 49s
    7. Defining sub-surface scattering
      2m 4s
    8. Simulating translucency
      1m 19s
  3. 1h 8m
    1. Using Maya's standard shaders with mental ray
      7m 2s
    2. Comparing mental ray and Maya shader nodes
      9m 12s
    3. Creating mental ray shaders
      2m 32s
    4. Making sense of mental ray shaders
      10m 35s
    5. Introducing the mia_material
      9m 16s
    6. Creating a custom mia_material preset
      9m 17s
    7. Looking at car paint materials
      6m 43s
    8. Using subsurface scattering shaders
      13m 33s
  4. 1h 5m
    1. Understanding UV coordinates
      4m 26s
    2. Comparing NURBS and polygon UVs
      4m 48s
    3. Mapping polygon UV surfaces
      13m 1s
    4. Using texture maps for color and other shader channels
      8m 1s
    5. Applying and projecting 2D procedural texture nodes
      4m 0s
    6. Applying 3D procedural texture nodes
      7m 1s
    7. Using ramp textures
      8m 12s
    8. Setting up utility nodes
      6m 29s
    9. Using file texture nodes
      9m 41s
  5. 22m 36s
    1. Applying the turbulence texture
      9m 37s
    2. Considering the round corners texture
      4m 17s
    3. Improving skin detail with ambient occlusion
      4m 27s
    4. Applying reflection occlusion
      4m 15s
  6. 33m 6s
    1. Painting bump maps
      4m 14s
    2. Creating normal maps
      5m 24s
    3. Applying normal maps
      6m 17s
    4. Creating displacement maps
      9m 14s
    5. Troubleshooting displacement maps
      7m 57s
  7. 33s
    1. Goodbye
      33s

Start learning today

Get unlimited access to all courses for just $25/month.

Become a member
Sometimes @lynda teaches me how to use a program and sometimes Lynda.com changes my life forever. @JosefShutter
@lynda lynda.com is an absolute life saver when it comes to learning todays software. Definitely recommend it! #higherlearning @Michael_Caraway
@lynda The best thing online! Your database of courses is great! To the mark and very helpful. Thanks! @ru22more
Got to create something yesterday I never thought I could do. #thanks @lynda @Ngventurella
I really do love @lynda as a learning platform. Never stop learning and developing, it’s probably our greatest gift as a species! @soundslikedavid
@lynda just subscribed to lynda.com all I can say its brilliant join now trust me @ButchSamurai
@lynda is an awesome resource. The membership is priceless if you take advantage of it. @diabetic_techie
One of the best decision I made this year. Buy a 1yr subscription to @lynda @cybercaptive
guys lynda.com (@lynda) is the best. So far I’ve learned Java, principles of OO programming, and now learning about MS project @lucasmitchell
Signed back up to @lynda dot com. I’ve missed it!! Proper geeking out right now! #timetolearn #geek @JayGodbold
Share a link to this course

What are exercise files?

Exercise files are the same files the author uses in the course. Save time by downloading the author's files instead of setting up your own files, and learn by following along with the instructor.

Can I take this course without the exercise files?

Yes! If you decide you would like the exercise files later, you can upgrade to a premium account any time.

Become a member Download sample files See plans and pricing

Please wait... please wait ...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ.

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

Join now "Already a member? Log in

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed Creating Textures and Shaders in Maya.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member?

Become a member to like this course.

Join today and get unlimited access to the entire library of video courses.

Get started

Already a member?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferencesfrom the dropdown menu.

Continue to classic layout Stay on new layout
Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Are you sure you want to delete this note?

No

Your file was successfully uploaded.

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.