Mental ray FAQ

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Contents 1 mental ray FAQ 1.1 What is mental ray? 1.2 Is it any good? 1.3 How much does it cost? 1.4 Where can I get it? 1.5 Maya, 3DS Max and XSI all have mental ray ... which is better or worse? 1.6 Are there official mental ray books? 1.7 Are there official mental ray training DVDs? 1.8 I don't need to render anything of super photorealistic quality, can I just use mental ray for 'normal stuff'? 1.9 I really like mental ray! Can I set it to be my default renderer in Maya? 1.10 What does mental ray have that the Maya Software renderer doesn't have? 1.11 I keep on hearing about this or that mental ray shader, that does <insert potentially confusing term here>, what are these shaders? 1.12 Ok, so where do I get some of these 'cool' shaders from? 1.13 Wait a minute, I'm having a revelation! If 3DS Max, XSI and Maya all have mental ray integrated now, does that mean a mental ray shader created for Max or XSI will work in Maya? 1.14 Does Maya come with any mental ray shaders? 1.15 Err, I don't see them! 1.16 Cool, what do they do? 1.17 How do I use them? 1.18 Are new mental ray shaders easy to create? 1.19 I want a shader that creates pink firey water! Can you make it for me? 1.20 Has mental ray ever been used to render a full length CG film? 1.21 Can mental ray do 'toon/cel/anime' style rendering?

mental ray FAQ

A modified version of Jared Martin's original "mental ray FAQ", tweaked by Zap; feel free to correct and modify, it's a wiki, afterall ;)

What is mental ray?

mental ray is a renderer that has been created by mental images. It's available both as a stand-alone application (which then renders .mi files) or integrated into many many 3D applications, such as 3ds max, Maya and XSI, as well as CAD software like AutoCAD, Solidworks, etc.

Is it any good?

Yes! It is regarded as the industry standard renderer for doing photorealistic rendering. It can do all the fancy things that a renderer needs. mental ray has been used to render scenes from movies such as the Matrix trilogy, Panic Room, Fight Club, The Hulk, the Starwars movies, The Day After Tomorrow, Poseidon...

How much does it cost?

Well, for the average user, nothing! If you own XSI, Maya (from version 4.5) or 3ds max (from version 6), mental ray is free as part of the software. mental ray can also be bought as a stand-alone rendering application, which is what you'd need for advanced studio pipelines.

The stand-alone version is not required to do rendering on lots of computers (ie a render farm) - you can use the satellite feature for that - but it is more flexible when doing this.

Where can I get it?

If you own any of the above mentioned applications, you already have it. It's built in as one of the standard renderers, although it may or may not be selected for you by detault.

Maya, 3DS Max and XSI all have mental ray ... which is better or worse?

Well, who most recently released a product? They are most likely the ones w. the currently most mature mental ray implementation. Today both Max and Maya both have mental ray 3.5 integrated into them, with XSI's mental ray 3.5 driven product released around end of year 2006. mental ray is mental ray no matter what it looks like integrated into a 3D package. However, the integration is what you can describe as better or worse.

I don't think many people would argue with me when I say that XSI has the 'best' integration of mental ray. Why? Because XSI has used mental ray as it's sole renderer since version 1. mental ray is completely integrated into every aspect of XSI, it's fast and easy to use (if you like XSI).

Maya's current integration (in Maya 8) is very good, but has room to improve. Most of Maya's features are supported for rendering in mental ray, and most of mental ray's main features are accessible through Maya. For a list of limitations, see the help files.

The 3DS Max integration tends to be more "automated", hiding some complexity from users. For example, when a 3ds max user uses the photometric lights, all photon emission calculation is automatically correct and set up with no user intervention, whereas in Maya one tend to need to consider ones photon shader and energy values. One of the selling points of the 3dmax integration is that a single license of 3dmax gives you an unlimited number of mental ray licenses as long as you use Autodesk's render queue called Backburner.

The bottom line is, that each integration has a slightly different "focus", and it is nigh impossible to grade them on a "better" or "worse" scale, until you answer the question "better for what?"

Are there official mental ray books?

Yes. Mental Images has written two books on mental ray. They are called 'Rendering with mental ray and 'Programming mental ray. The latter book requires programming knowledge (ie C++), but the first book is just a good handbook. Something you really need to know is that there are first and second editions of each of those books! Make sure you get the second editions if you can because you don't really want to buy an outdated book. Unfortunately the second editions are named the same as the first ones, and look nearly identical too (I think!). You can buy the books by clicking here !

A 3rd edition of 'Rendering with mental ray has been released. Not only is it updated for mental ray 3.4, it also contains the entire second edition of 'Programming mental ray on the CD that comes with it!

Are there official mental ray training DVDs?

Not by Mental Images themselves, but Alias Gnomon and digital tutors has created some::

mental ray Custom DVDs

I don't need to render anything of super photorealistic quality, can I just use mental ray for 'normal stuff'?

Yes you can. mental ray is an all-round good renderer, not just for photoreal film animation/effects. It's fast and reasonably simple to use for every-day renders of your models and scenes. However, if you're just starting out in Maya and like to experiment with all of Maya's great crazy features, you might be better off sticking to the Maya Software renderer. Just so that you don't have to worry about any compatibility issues.

I really like mental ray! Can I set it to be my default renderer in Maya?

Yep! Go to:

Window > Settings/Preferences > Preferences

From the left hand side list of catagories, click on Rendering. Then in the main section on the right, select mental ray as your preferred renderer. Note, if you don't have the mental ray plugin set to 'autoload', next time you start Maya there could be problems because it won't be able to find it's preferred renderer!

What does mental ray have that the Maya Software renderer doesn't have?

Well, a lot of things really. Some of the more significant features are Global Illumination through both radiosity and photon mapping, Caustics, motion blurred shadows and reflections, volume caustics, Final Gather, photometric lighting.......and lots more.

If you went "wuh??" to any of those terms, don't worry. There is a glossary type of thing further on in this post/thread.

I keep on hearing about this or that mental ray shader, that does <insert potentially confusing term here>, what are these shaders?

mental ray shaders are a big part of mental ray's power. Unlike the normal use of the word 'shader' that you probably know about, describing a material that looks like concrete, or grass or whatever, mental ray shaders can do many more things than these traditional shaders.

A shader in mental ray could still make something look like grass, but it could also create a light! Or create geometry! It could change the lens on your Maya camera, or apply an effect like fog or depth blur to your scene. mental ray shaders basically make up most of your scene. Of course, you don't really need to know that because Maya takes care of most of these shaders in the translation of your Maya scene at render-time.

However, if there's an effect or look that you need to achieve, and Maya doesn't already have a feature for it, say for example Sub-Surface Scattering, Ambient Occlusion or a a Telephoto Lens (sorry for the technical terms, more on them later), a mental ray shader can often come to the rescue.

To sum all that up, mental ray shaders are cool and can do lots of useful things!

Ok, so where do I get some of these 'cool' shaders from?

The internet. Or if you're really smart and know how to program, you could try writing them yourself. Now that mental ray is becoming a lot more mainstream, more and more shaders are being created by artists, and posted for free on the internet. Which is really great! They're a bit scattered around on message boards and personal websites though, so if I (or you) find any cool ones we should post them in this thread for easy access.

Wait a minute, I'm having a revelation! If 3DS Max, XSI and Maya all have mental ray integrated now, does that mean a mental ray shader created for Max or XSI will work in Maya?

Basically yes! Not right away though. There are a few files that make up each shader (more on that later), and only the mental ray specific parts will be compatible straight away. The other files for the shader tell the specific 3D program how to use them, and what the interface for the shader should look like. Someone needs to create Maya specific versions of those files in order for them to work properly (or even load) into Maya. Luckily, if a great shader is created for Max or XSI, chances are that someone will soon port it over to Maya.

Isn't that kinda nice? Shaders re-uniting the global community and breaking down the barriers between 3D apps? Ehem, just forget I said that part.

Does Maya come with any mental ray shaders?

Yes. If you look in the Hypershade, or that popup window that appears when you click on a mapping slot next to an attribute of a shader, you should see a section called mental ray (how surprising!) that has quite a lot of shaders in it.

Err, I don't see them!

Yes I know, hehe. If you have Maya 4.5 or even 5, chances are you won't see these mental ray shaders. They need to be specifically loaded. I have a tutorial on loading these shaders here! Maya 6 should definitely have them loaded by default.

Cool, what do they do?

Umm, stuff. There are too many to explain each one here, and depending on your version of Maya, some of them might not work properly anyway. The best way to learn about them is to just follow tutorials on mental ray that you think look cool. If a tutorial requires you to use one of the shaders, it should hopefully tell you all about it. (I know I do in my tutorials)

How do I use them?

That's a similar question to the one above. Just follow tutorials and they'll tell you how to use each the different shaders.

Are new mental ray shaders easy to create?

Well....generally no. Not for the average user. In order to create a brand new shader you need to know how to program in C, compile the code etc.

I want a shader that creates pink firey water! Can you make it for me?

Sorry love, the pink firey water will have to wait. I'm afraid I don't know much programming at all, therefore I can't write you a new shader! Cheer up, someone who does will surely need pink firey water some day too.

Has mental ray ever been used to render a full length CG film?

Sure, movies done 100% using mental ray include:

- Arthur and the Minimoys

- Happily N'Ever After

- The Magic Roundabout

- Pinocchio 3000

In addition, many tv series have used it exclusively, too, including:

- Beast Wars

- Dragon Booster

- The New Adventures of Spiderman

- Reboot (2nd season and on)

Other animated productions have used mental ray partially:

- Most recent Studio Ghibli productions (Princess Mononoke, Spirited Away, etc)

- Most recent films from Production I.G. (Innocence, etc)

Or as a complement to a propietary in-house renderer:

- Shark Tale

Besides this list, mental ray has also been used to render literally thousands of special effects shots in movies since the 90s.

Can mental ray do 'toon/cel/anime' style rendering?

Yes, in mental ray this type of effect is called Contour rendering.

End of FAQ for now!