Mental Ray Interior Lighting Setting Tutorial

Hello! Today let's talk about Mental Ray. What is mental ray? Mental Ray is a production-quality rendering application. Just like Vray but, in my opinion, rendering time is much smaller. So if your computer resources not helps you too much , my advice is to learn both rendering engines and use the one that suits you best.

This is a simple tutorial. I made a small room, with a few object, I already choose materials, mental ray materials and Arhitecture materials(you can do this after you set the mental ray parameters or from beginin) and i will show you the Mental Ray settings. We will using "natural" light casting through a single window.
If you ever hope to achive good-looking 3D scenes you need to know a couple of things about lighting in general. 

This is my initial scene. From here will begin with our light and settings.

In this tutorial , we going to use dow lights, since we'll be using Mental Ray's Global Illumination algorithm. Go to 3DS Max's Systems tab ans place in your scene a Daylight system. Set the time about to 9 AM. When you select Daylight you will recive a message. Ignore and click OK.

Go to 3DS Max's Render Setup(F10 on your keyboard), click the Common tab, scroll down and roll-out the Assign Renderer panel. Assign the mental ray renderer as the default production one. You can render to see the result(press F9). Not that impressiv.. but don't worry will fix it.

Click the Daylight System and set the Sunlight to mr Sun and the Skylight to mr Sky. Click OK on whatever pops up.

Switch to Perspective view and render again. 

A little bit better already. To get the light photons to bounce, open 3DS Max's Render Setup window (F10), go to Indirect Illumination tab, scroll down and enable the Global Illumination. Also set the Average GI Photons to 50 000.

Switch to Perspective view and render again. 

Almost there. Riht now the scene is a bit dark. To fix this, click the Daylight system, and set the Multiplier to 3.2 .

Now to emphasis the area that the light hits we are going to create a pseudo fill light. Place a mr Area Omni in the center of the room and:
- un-check the Shadow box
- set the Multiplier to 6
- the Decay to Inverse Square
- the Start of Decay to 1500

Render again.

Looks good, but we've lost the reddish tint that we were trying to get. To fix this, click the Daylight System, the Modify tab, scroll down to the mr Sky Advanced Parameters and set: 
- the Red/blue tint to 0.7
- the Horizon height to -1 to make sure it converse the entire scene
- the Saturation to 1

Render again

Finally, to prepare for the final rendering, open up 3DS Max's Render Setup, Indirect Illumination tab, and set the Gather Precision to low or medium. 

Switch to Perspective view and render again.

Hope this will be helpful to you. Don't hesitate to play with settings and to practice for better or different results. Bye!