Mental Ray Titles Dec13

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Mental Ray Titles

Welcome to an exciting tutorial on creating photorealistic lighting in 3ds Max. It’s exciting because it is not just about creating renders that look great. The focus is on creating better renders without exponentially increasing the time it takes to render. So, this tutorial is really about getting the best balance between rendering time and photorealistic results.

3d computer lighting is not the same as lighting in the real world. A beginner must understand that if you are trying to generate photorealistic images that 3d programmes are actually setup for you to fail.

default vs. photorealistic

default vs. photorealistic

For example, almost every single light source in a 3d package DOES NOT produce light like the lights you encounter in real life. One tell tale sign is the shadow. Computers like crisp definitions… real life lights, however, cast soft decaying penumbras that aren’t very crisp.

far vs. close

far vs. close

Another problem with computer lights is how they react to the polygons in a scene. For example, if you take a real-life light source and bring it closer to an object… that object appears brighter. BUT, if you take most 3d lights closer to an object, that object actually appears LESS LIT because there are fewer polygon faces actually facing (ie. visible to) the 3d light.

Now, there are a couple of lights that do behave like real-life lights. The first set uses a database of illumination values based on actual lab-controlled benchmark tests: photometric lights. They use a table of data that conforms to the IES or Illuminating Engineering Society standard. Another, are computer-systems of light groups: for instance, 3ds Max’s daylight system.

When thinking about lighting a scene, it’s handy to use proper photometric/system lights for the main fill, or ambient light, and then use regular-nonrealistic lights as CHEATS to enhance specific elements in a scene. After all, a well-lit scene shouldn’t be a point-and-click snapshot… a well-lit scene should draw attention to certain elements as well as create pools of shadow-casting areas for contrasting emphasis and realism… these highlights and “shadow casting” lights are best handled with cheats from regular 3d lights.

An example of a well lit scene that uses cheats and shadow-casting lights as much as proper photorealistic illumination can be found here:ladybug

TUTORIAL

Mental Ray is used here for a few reasons.

First, it’s available within 3ds Max without the need to purchase additional plugins. This makes my tutorial more accessible.

Second, Mental Ray integrates better into 3ds Max than the other rendering plugin. 3ds Max has a number of tools that deal exclusively with managing your numerous assets in a scene. For example, the Light Lister is a tool that provides a one-stop panel for managing all lights in a scene. It allows you to change light values quickly, and provides fast on-and-off buttons for you to use as you fine tune your scene. Mental Ray lights saves you time by integrating well with this tool… V-Ray, not so much.

Third, V-Ray (the defacto alternative to Mental Ray) on animated sequences for film has been known to have alpha matte issues around the edges of objects rendered under daylight systems. This means, you can spend plenty of time tweeking your 24 fps animated scene just right, only to find out that you need to clean your mattes in post during the compositing phase. This problem happens less frequently using Mental Ray. So, this tutorial will not be using V-Ray.

Step 01 Initialize your Settings
A separate colour grading package will be used on our images. There is a lengthy discussion about using gamma curves that are different than the curves used for your computer monitor. In short, my image will be created using a logarithmic 2.2 gamma curve for processing in a separate colour grading package.

The first preferences to adjust are the Gamma/LUT (ie. Look-Up Table) settings (Customize > Preferences > Gamma and LUT tab) according to the following:

  • Enable Gamma/LUT Correction: CHECKED
  • Display: Gamma DIAL ON
  • Display: Gamma: 2.2
  • Materials and Colors: Affect Color Selectors: CHECKED
  • Materials and Colors: Affect Material Editor: CHECKED
  • Bitmap Files: Input Gamma: 2.2
  • Bitmap Files: Output Gamma: 2.2
Initialize Preferences

Initialize Preferences

Step 02 Create a Studio Backdrop
Create a plane (Create panel > Geometry > Standard Primitives > Plane) in the top viewport. Modify the Plane (Select > Modify panel) according to the following:

  • Length: 70
  • width: 70
  • segments: 8
create a plane

create a plane

Apply a Bend modifier (Modify panel > Modifier list > Bend) according to the following:

  • Angle: 180
  • Bend Axis: X
apply Bend modifier

apply Bend modifier

Step 99 Save Render Settings as a Preset
One reason that I created this post was so that I could have a reference to go back to in case I forgot any individual setting. Of course, the easiest way for you to accomplish the same task is to save the render settings as a preset. Presets saves more than just the render tab information. Decisions about logarithmic exposures, effects and other render tabs are saved in one convenient spot. Your preset is saved as a menu item that is easy to use in future projects.

preset

preset