Maya Exterior render tutorial (Mental Ray)

Posted by Antonio
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Here we are going to see a very simple but effective technique to lit and render your exterior scenes using Maya and Mental Ray renderer. The Mental Ray built-in Sun and Sky system is one of the more powerful tool inside maya. Some people are tempted to think that it's something for noobs and starters... believe me it's not!

TYPE: Free maya render tutorial
CATEGORY: Maya exterior render, Mental Ray Exterior


We are going to take a look to one of the most useful features in Mental Ray: Physical Sun e Sky.
If you enjoy in creating exterior renders in Maya this simple guide will help you understand and use the best tool that mental ray have to achieve exterior renders.

Let's get started!



Open the exterior scene you want to render in Mental Ray but be sure to make it the more simple that you can. For this first step we need something very light, a heavy scene can drammatically increase your working time...keep the details for the final renders!

I kept the main building and a small number of proxy trees (those wireframed cubes), just to give a starting sense to my exterior scene.

Open maya exterior render scene


Assigning a base material to the whole scene will help us creating and tuning the overall light setup. My advise is to use a native Mental Ray shader. I will go for a mia_material_x_passes......Why you should use a mia_material instead of one of maya shader?

Mia_materials are the most complete shaders in the mental ray's family. You can use these shaders to make every kind of material (from glass to iron), they are fast, stable and supports multipass outputs (with the mia_material_x_passes shader). Mia_materials are also known as "Arch & Design" materials, that's because they have many characteristics that makes these materials both physically accurate and flexibles.

These settings for the Mental Ray's mia_material could be a good starting point (gray diffuse and 0 reflectivity):

Assign base material for exterior render

Assign a material to the glass surfaces also (go with mia_material_x_passes again) but this time you can load one of the maya's presets (REPLACE 100%). NOTE: when working with glass/transparent surfaces be sure to increase the raytracing render settings or you will see weird things!

mental ray material preset in maya Mental ray render quality tab in maya

If you hit render you should get something of horrible like that:

Maya exterior render tutorial base


Create Physical Sun and Sky from Mental Ray render options tab:

Create Mental Ray physical Sun and Sky in Maya

Now if you click render, you should go from that:

Maya base exterior render

to that

Maya exterior render with mental ray sun and sky enabled

How Mental Ray made this magic possible in a single button click? Let's take a look at Mental Ray Physical Sun and Sky's nodes:

Mental Ray sun and sky nodes

That's what Mental Ray does:
1) Create a Physical Sky Dome 2) Create a directional light (Sun) 3) Create a tonemapper 4) Enable indirect light calculation (Final Gather)

What are these nodes and what they does? Let's take a deeper look to them....


Mental Ray's Physical Sky is connected to the persp camera trough the Mental Ray's environment tab

Mental Ray physical sky camera connection in Maya


A Sky Dome is an hemisphere that surrounds our scene. That hemisphere has a light emissive textured attached to, that texture is based on a Physical Sky model (Mental Ray should use the Preetham sky model ).


Mental Ray physical sky dome schemeExterior render Prethaam model skylight

A Physical Sky Dome is very important because its light contribution is HUGE, in quantity and quality therms:
a sky dome emit an extreme soft type of light (the opposite of the harsh direct sun light), that kind of light is very eye-pleasing. This is the reason why professional landscape photographers try to take their pictures just when the sky dome light contribution is higher than the sun power.

The combination of that 2 light sources (sun and sky) creates the typical and realistic daylight

Exterior render physical sky Mental RayExterior render physical sun Mental Ray
Physical Sky light contribution only                                             Physical Sun light contribution only

Exterior render physical sky + sun Mental Ray
Sun light + Sky light

What makes the Physical Sky Dome a soft light source lies in it's nature: it is an indirect type of light.
Infact the sky is enlighted by the Sun (a direct light source) this light travels and scatters through the athmosphere and finally hits our scene. After all this journey the indirect sun light has become an omnidiectional / very diffuse light.

Sky light scattering schemeSky light scattering in atmosphere scheme

IMPORTANT NOTE: You won't see any Physical Sky effect if you don't turn on Mental Ray Final Gather (indirect lighting computation),
so be sure to put Final Gather ON when you work with Physical Sky.

Exterior render sky (Final Gather off)Exterior render sky indirect illumination (Final Gather on)
Final gather OFF                                                                             Final gather ON


The sunDirection node is created at the center of the scene and it has the apparence of a standard directional light... but it's much much more!

Mental Ray Physical Sun in Maya nodeMental Ray Physical Sun in Maya node chain

Mental Ray Sun is directly connected to Physical Sky, driving the overall aspect of the environment.

By simply rotating the sunDirection light you can change the time of the day.
This aspect of the overall illumination should be the first thing you should figure out: find the right time of the day can drammatically enhance your renders.

I often set the time of the day using the IPR render fetures in Maya, in that way I get an instant feedback of what I'm doing.

Mental Ray exterior render physical sky and sun time of the day


A tone mapper is created (mia_exposure_simple) and connected to the camera through the Mental Ray's lens shader tab.

Mental Ray tone mapper connection to maya's camera

A tone mapper simulates the real camera behaviour. If you are familiar with real photography you know that your camera is responsible of many fundamental aspects such exposure, depth of field, grain, white balance and so on.... the most of that things are driven by tone mappers.

One of the one tonemapper's primary duty is to balance the luminance between high luminance and low luminance pixels coming from our renders.

Mental Ray tonemap response curve

The tone mapper elaborates the full spectrum of the image to make it more eye-pleasing (in tech terms it converts an HDRI image in a low dynamic range image, to make it easly readable by our eyes trough our displays). It has to do with response curves, parameters and types...but for now just keep in mind that tone mappers are essentials for any convincing computer generated images.

Mental Ray exterior render tone mapper offMental Ray exterior render tone mapper on
Tone mapper OFF                                                                               Tone mapper ON


Mental Ray physical sky attributes tab in maya

Let's take a look at the controls that I tweak in the most of the cases when working on exterior render scenes. If you are looking for a deep explanation of every single attribute and connection please refer to some technical sheet.

MULTIPLER is the overall strenght of the sky light emission. The default is 1.0. I often leave it as is, this parameter can help you in complex light situations (for example when you are doing evening scenes where you have to combine natural and artificial light).

HAZE: it sets the amount of haze/fog in the air. The range start from 0 (clear day) to 15 (overcast/desert storm). The haze parameter influences the apparence of the sky and horizon, but it's also drive the softness and the strenght of the sun light. Use this parameter to give a more realistic appeal to the overall environment, I dislike extreme parameters (0 and 15).

Mental Ray for Maya physical sky haze for exterior renders

RED/BLUE SHIFT: it is a tonal correction (from blue to red). You can easly correct the warmth of the atmopsphere. The default value is 0.0, values higher than 0 will make your atmosphere more red (warmer), values below 0 will make the atmosphpere bluish (colder). I correct it very little to avoid unnatural effects (expecially in the sky).

Mental Ray for Maya physical sky red/blue Shift for exterior rendersMental Ray for Maya physical sky redness for exterior renders
RED/BLUE SHIFT +0.3                                                                       RED/BLUE SHIFT -0.3

SATURATION: I guess it's self explanatory... 0.0 black and white, 2.0 extremely saturated! This parameter will allow you to control how much color will cast the sky dome/sun.

NOTE: if you tune sky's saturation you will probably obtain a very unnatural sky, so remember to replace the sky in post...this parameter is intended to use for an artistic control over the casted light, or small changes.

Mental Ray for Maya physical sky saturation attribute (desaturated) for exterior rendersMental Ray for Maya physical sky saturation attribute for exterior renders
Saturation 0.0                                                                                    Saturation 2.0

HORIZON HEIGHT: sets the "level" of the horizon. This parameter has to be fine tuned to fix horizon issues when doing exterior renders from a high camera point of view.

Mental Ray for Maya physical sky horizon height attribute for exterior rendersMental Ray for Maya physical sky horizon height (less) attribute for exterior renders
Horizon height 0.00                                                                             Horizon height -0.62

SUN DISK INTENSITY: do you think is the luminance value of the disk sun? No! It's something like sharpeness. The more this value, the more visible will be the sun disk. This parameter will not alter the overall casted light, it's just a sun apparence setting.

Mental Ray for Maya physical sun disk intensity for exterior renderingMental Ray for Maya physical sun disk intensier for exterior render
Sun disk intensity 1                                                                            Sun disk intensity 50

: sets the size of the visible sun disk. Like the "Sun Intensity" this parameter will not alter the overall light casting, it's just an apparence setting.
A fun fact: the real sun scale should be 1.0 but people always misunderstand the real scale of the sun so, for good looking reasons, this parameter is set
to 4.0 by default :) Feel free to tune this parameter following your tastes!

Mental Ray for Maya physical sun disk scale for exterior renderingMental Ray for Maya physical sun disk scale (bigger) for exterior rendering
Sun disk scale 1                                                                                  Sun disk scale 4

: glow_intensity is the intensity of the visible sun glow. This parameter will not alter the overall light casting, it's just a sun apparence setting.


Mental Ray for Maya physical sun disk glow for exterior renderMental Ray for Maya physical sun disk glow (bigger) for exterior rendering
Sun glow_intensity 0.2                                                                        Sun glow intensity 4


Mental Ray Physical Sun is connected to the Physical Sky node. If you open up the attribute parameters of mia_physicalsun you will notice some values enlighted by a yellowish color: those attributes are driven by Physical Sky node's attributes so if you change, for example, "horizont height" in Physical sky the relative attribute of the Sun node will automatically get the same value.

Mental Ray for Maya Physical Sun attributes tab

SHADOW SOFTNESS: controls the softness ammount of Sun light. Higher values will soften Sun's shadows.
The physical accurated value is 1.0, but I often put this numer higher (something around 2 or 4).

NOTE: This is a scene scale dependent effect, so you have to fine tune this parameter everytime in all your scenes...there's no magic-one-time-set value parameter! Bigger scenes will require higher values to get the same effects of the small ones.

Mental Ray for Maya Physical Sun softness attribute for exterior rendersMental Ray for Maya Physical Sun softness attribute (more) for exterior renders
Softness 1.0                                                                                     Softness 4.0

SAMPLES: it controls the quality of the Physical Sun's soft shadows. If you notice grainy sun shadows then put that number higher
(the less than you can or your render times will go crazy!)

Mental Ray for Maya Physical Sun samples attribute for exterior rendersMental Ray for Maya Physical Sun samples attribute (more) for exterior renders
Samples 4 (0:51 min)                                                                         Samples 128 (4:30 min)


Let's take a look at the tone mapper created by Mental Ray Physical Sun and Sky: mia_exposure_simple

Mental Ray for Maya mia_exposure_simple attributes tab

GAIN: it represents the exposure knob. Raise or lower this value to set the overall brightness.
This is the first parameter to set, the other parameters are related to this one.

Mental Ray mia_exposure_simple gain for exterior renders in mayaMental Ray mia_exposure_simple gain (more) for exterior renders in maya
Gain 0.5                                                                                           Gain 1.5

: this control will manage the highlights of your render. The more the value, the less the highlights.
A value of 0.0 means no compression at all (so lots of highlights and probably lots of burned areas). Values around 2-4 are advised.
Don't compress to much or you will loose all the contrast (even if you will recover burned areas).

Mental Ray mia_exposure_simple compression for exterior renders in mayaMental Ray mia_exposure_simple compression (more) for exterior renders in maya
Compression 0                                                                                   Compression 10

: sets the gamma correction of the resulting tonemapped images.
We should have a long talk about gamma.... but for now be sure to set something between 1,8 and 2,4 (gamma changes the response of the mid-low tones).
Take a deeper look to gamma speech if you are interested in linear workflow.

Mental Ray mia_exposure_simple gamma (2.2) for exterior renders in mayaMental Ray mia_exposure_simple gamma (1.8) for exterior renders in maya
Gamma 2.2                                                                                       Gamma 1.8

PEDESTAL: it tweaks the "black level". A positive value will add some light, a negative value will make your blacks deeper. Use it just as an artistic option.
I often use this parameter to crush blacks.

Mental Ray mia_exposure_simple pedestral (0.1) for exterior renders in mayaMental Ray mia_exposure_simple pedestral (-0.1) for exterior renders in maya
Pedestral 0.1                                                                                     Pedestral -0.1

Tone mappers are essentials in exterior render tecniques because exterior scenes have a lot of unbalanced lights (tons of highlights and deep blacks), Mental Ray's tonemappers are our best friends to balance and tweak our rendered images.

Be sure to spend some time in tweaking mia_exposure_simple, this will enhance your exterior renders a lot.


Now that we had setup the overall light parameters we are ready to assign materials. My advise is to use mia_materials (simple, x or _x_passes).
When tweaking start with 0 reflections and refractions, tune your diffuse channel (with a base color ), play with roughness and try to achieve a good looking result with base parameters.

Mental Ray exterior render base material setup

After that assign a texture to the diffuse channel.

Mental Ray exterior render diffuse texture in mia_material

Go with a bump map to enhance the level of detail.

Mental Ray exterior render bump map texture in mia_material

Activate ambient occlusion to add some contact-contrast.

Mental Ray exterior render Ambien Occlusion (AO) in mia_material

When you think these parameters are pretty good, start play with reflection.

Reflections are essentials to achieve photo realistic looks. Keep that in mind: every object in real life is reflective, there is no 0 reflective objects in the real world... you just need to set reflection parameters properly (I know.. it's not so easy!).

Mental Ray exterior render reflections fine tune in mia_material



In this tutorial we will not cover an in-dept guide to make garden and plants, but I hope to write a specific tutorial soon.

We can't get a nice exterior render if we don't take care of the environment, in particular grass and plants. This step is crucial.
To make a decent natural environment the first step is find good references, so go on google and steal some ideas...because, as the good old Picasso said:
"Good artists copy, great artists steal!"

I usually make a base grass carpet and then I place the other plants. I highly recomend you to take a look to the Maya Mental Ray Proxies Tutorial where I explain an effective tecnique to populate maya scenes with hundreds of complex objects (like grass and trees!).

Get pratique in gardening and your exterior renders will jump many quality levels. A great garden can make an horrible scene become very good!


Have properly set up lights, materials and environment? Then you just need some final touches and a good background!

Mental Ray exterior render with physical sun and sky no cloudsMental Ray exterior render with physical sun and sky with clouds

A nice background is very important, sometimes a good background can bring life to a dead render. The Mental Ray's sky background is a simple / boring colored gradient. You can easily get rid of it in post production.
NOTE: Physical Sky supports a BACKGROUND slot allowing you to insert a background directly in you renders, but I find the post production approach more effective.

Be sure to launch you final renders with Mental Ray High Quality render settings (and high resolution), then make some adjustments in post production.
There's no rules in post production (you can do anything you like), I often adjust levels and do some color corrections.
I come from the old school "Do the most of the job in the render phase and just little adjustments in post-production". But you are free to find your own approach.


Exterior render scenes are one of the most difficult challenge for a 3D graphic Artist, that's because not just for its complexity but also because of its weight (in power calculation therms). Mental Ray Sun and Sky is the fastest and powerfull way to enlight you exterior renders in Maya, so I hope you will spend much time to learn how master all its features.

When playing with that kind of scenes keep always in mind that exterior render scenes are very heavy, they will overload your CPU and your RAM (expecially when you are going to add nature and trees), this will make you waste a lot of time just to get render feedbacks during your work, even if just for small changes... it can be very frustrating and, above all, it will make your job a hell !

That's why I VERY advise you to...

1) Keep things simple, add details and heavy geometry just in the final stages
2) Setup a little Render Farm, this will allow mental ray work much faster (and happier!!)

Adding a Mental Ray render node into your pipeline can massively improve your workflow,
that's why you should take a look at Setting Up a Render Farm in Maya and Mental Ray Tutorial .

We took a first look to Mental Ray Sun and Sky, but there are still a lot of different approaches that we can use to make great exterior renderings.
I think Mental Ray Sun and sky is VERY good for the 80% of the exterior render jobs, for the remaining 20% we should take a look at different/advanced tecniques.

In the future (I hope a near future!) we will take a look at other effective exterior render tecniques in Maya and Mental Ray. We will also go deep in Mental Ray Physical Sun e Sky to see how it can be combined with other tecniques and how you can achieve special (and very cool!!) athmosphere render effects.

Happy rendering!


exterior render tutorial mental ray maya



#1 +1 Tzadi 2013-04-18 14:31
Looking forward to it. Keep up the good work.

#2 +1 Antonio B 2013-04-19 08:59
It would be the next ;) thx for the support!
#3 +1 Marcos Ribeiro 2013-04-26 10:19
Hi Antonio, when can we expect this tutorial? This will cover just mental ray sun and sky or some materials too?

#4 0 Antonio B 2013-04-26 11:20
Hi Marcos,I'll probably write this tutorial in the next 1/2 weeks. I'll discuss about enlight efficently an exterior scene using mr sun&sky with mr materials. This tutorial will be a starting point for further and advanced tutorial that will cover materials, plant/grass creation, tonemappers, post production and more. Hope to make all this stuff soon!
#5 0 Marcos Ribeiro 2013-04-26 13:59
Alright, keep going the excellent work! By the way, thanks for the olive trees update (turbosquid), works like a charm!
#6 0 Ian 2013-04-29 08:44
Really expect this :D
#7 0 Richie Pichler 2013-06-10 17:11
Can't wait to see this tutorial!! Do you know, when you will have time to finish it?!? thanks alot!
#8 +1 Antonio B 2013-06-16 14:13
Hi guys, sorry for the late. I'm working hard on too many projects!
I'm setting up the scene for the tutorial on these days! Hope to have the full tutorial for the first weeks of july. Thx for the support!
#9 0 Andres 2013-07-06 03:11
thanks for taking time to do this tutorials,cant wait for this one!!!
#10 0 Tzadi 2013-08-26 11:47
We will wait patiently for it! Thanks in advance and good luck with those projects you´re working on. Cheers
#11 +2 Antonio B 2013-08-31 15:32
Tutorial Up!! Thanks for your patience!
#12 +3 jayzu 2013-09-02 16:49
Very Helpful,
Thank you Good sir ;-)
Will be tryin these techniques to improve my work and be looking forward for more Cookies :lol:
#13 0 Vitalik 2013-11-27 03:30
#14 0 Subin Antony 2014-03-12 05:25
:lol:thank thank.................good very well i do not know what to say
#15 0 Leandro Pozo 2014-05-18 19:45
Thanks for the tutorial. great job. o/
#16 0 Abdo 2014-09-17 16:10
Amazing man, thanks a lot...
#17 0 rahro 2014-11-20 18:36
hi for best software for rendering? maya-max-rhino-cinema4d-modo
#18 0 Antonio B 2014-11-20 18:47
Hi Rahro, any sotware has pros and cons! But I prefer maya over any other software ;-)
#19 0 kahpoh 2015-03-06 03:38
Hi, your tutorial is amazing. But my things always look flat when I render with physical sunlight, I do follow your tutorial, maybe my models and textures not good enough. I'm waiting for the grass and plant tutorial!!!!!!! Thank you!
#20 0 M 2015-04-26 08:36
hello! Great tutorial, explains everything in great detail. I jave one question are you able to explain how you created your grass?? Or at least point me in the right directon?

#21 0 Antonio B 2015-05-15 09:22
Quoting M:
hello! Great tutorial, explains everything in great detail. I jave one question are you able to explain how you created your grass?? Or at least point me in the right directon?


Hi "M", maya paint-fx is great for grass creation ;-)
#22 +1 - Luc - 2015-06-01 17:56
Hi Antonio,
what a great & useful MR tutorial!
many thanks for your effort.
#23 0 mancaps 2015-06-21 20:54
Thanks for finally writing about >Exterior render tutorial
in Maya and Mental Ray
#24 0 Parrot 2015-11-23 12:32
Thank you very much!!
#25 0 Francois Zab 2016-06-20 18:21
Hi Antonio,
Thank you for your very nice tutorial. I'm switching from 3DSMAX and Vray to Maya and mental ray. I'm actually doing an external render and your tutorial is great. Unfortunately i'm blocked at the beginning because my glass material remain black without GI, and then a minor aspect with GI. I'm sure it is nothing but painful ;-)
Can you help with this?
#26 0 Antonio B 2016-06-21 19:06
Quoting Francois Zab:
Hi Antonio,
Thank you for your very nice tutorial. I'm switching from 3DSMAX and Vray to Maya and mental ray. I'm actually doing an external render and your tutorial is great. Unfortunately i'm blocked at the beginning because my glass material remain black without GI, and then a minor aspect with GI. I'm sure it is nothing but painful ;-)
Can you help with this?

Hi Francois, did you raise the Trace Depth parameters under render options?
#27 0 ally 2016-06-22 21:05
great tutorial. even tho i am using 3ds max 2010, mental i finally got an understanding of the basics.
i hope you have more tutorials somewhere saved.

especially mental ray tutorials concerning external rendering

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