mental ray Workflows in Maya: Global Illumination

Learn creative practices for utilizing global illumination and time-saving rendering techniques that can be used in a multitude of applications. Software required: Maya 7 and up (Maya 2008 required for project files).
Course info
Level
Intermediate
Updated
Feb 4, 2008
Duration
2h 9m
Table of contents
Description
Course info
Level
Intermediate
Updated
Feb 4, 2008
Duration
2h 9m
Description

Learn creative practices for utilizing global illumination and time-saving rendering techniques that can be used in a multitude of applications. Contains 2 hours of project-driven training - Perfect for intermediate artists. Popular highlights include: Global Illumination Overview; Understanding Photons in mental ray; Emitting Photons from Various Light Sources; Controlling Photon Energy; Controlling Decay Rates; Altering Photon Color Attributes; Separating the Effects of Direct Lighting; Separating the Effects of Indirect Lighting; Tuning Global Illumination Scale; Tuning Global Illumination Radius; Tuning Global Illumination Accuracy; Photon Tracing with Transparent Surfaces; Global Illumination Photons Maps; Global Illumination with Final Gather; Using the Map Visualizer; Global Illumination Overrides; Photon Interaction with Maya Materials; Photon Interaction with mental ray Materials. Software required: Maya 7 and up (Maya 2008 required for project files).

About the author
About the author

Kyle was one of the first authors for Digital-Tutors (now a Pluralsight company) and has been a part of the team for over 10 years. Kyle began his career in computer graphics education as a college instructor and worked as a Digital-Tutors rendering tutor and curriculum manager since 2002.

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Section Introduction Transcripts
Section Introduction Transcripts

Introduction and Project Overview
[Autogenerated] Hello and welcome to the series of mental ray work flows in Maya Global Illumination presented by digital tutors and Auto desk authorized publisher. My name's Kyle and I'll be your instructor, guiding you through the process of using global illumination and mental ray to achieve a very high level of realism in your rendered environments. Now in the world around us, direct illumination only makes up a portion of the light that we perceive. A large amount of light that we see actually comes from indirect elimination or like that bounces off of the surface is to laminate our surroundings. Now in metal rate, this indirect lighting can be simulated with a feature called Global Illumination. And mastering this feature is an essential step toward creating highly realistic renders that closely mimic the weight. Light interacts with objects in the real world, so we'll begin our training by exploring photons and mental ray and the processes they used to simulate in direct elimination. From there, we'll take a look at the attributes used to control exactly how these photons interact with various materials and you're seen such as metal, wood, glass and cloth. We'll also explore some features usedto optimize your rendering times as well as many other practical lighting examples that are specifically designed to give you a stronger knowledge of global illumination in mental ray. So let's go ahead and get started with our first lesson on using photons. So within metal Ray, the term photon actually correlates exactly to what a photon doesn't really life, right? So in real life of photon is more or less a packet of energy that gets carried on individual light particles. Now, whatever, like particle strikes an object in real life, the photon of that light particle was actually able to capture lighting and color information from the surface is that it interacts with. So if a light particle were to strike an object, the photon of that light particle is gonna be able to carry the information or the color information on to the next surface that it strikes. So in real life, if you've ever taken any kind of a brightly colored object like a red ball or something and hold it up to a nice white surface, you're gonna notice that that white surface is gonna have a very distinct red tint to it, or a red coloring to it. And that's because the photons that we see in real life for the photons that are bouncing around in real life you're gonna be able to bounce off that red object and cast a red light onto the surface is that it interacts with. And this is exactly what photons do, and metal rays will. So just like in real life, a photon in metal ray is emitted from a light source. So in order to actually start to get any kind of food tons in our scene, we first need to add a light. Now, the food on could really pretty much come from any of these light types that we have available to us. But we do have to be somewhat careful as faras, which type of light that we want these actual photons to admit from. So, for example, if I were to choose a point light and drop this into my scene, this point light is going to actually emit photons out in the same sort of a pattern or the same distribution that it would admit normal direct lighting. So in the case of this point light, it's actually gonna be casting photons out in all directions. Now, in some situations that may be good in some situations that actually may not be so good. And here's the reason why the photon calculation within metal Ray or any kind of a rendering application is not going to be able to simulate the true number of photons that you were. I see on any point in time. So we have to actually be very careful about the number of photons that we admitted to our scene in order to keep a rendering time somewhat fast. So if you have a light source that's gonna actually be out in the middle of your room and casting these global illumination photons out evenly this point light worked quite well. But if I had a situation where the light source is gonna be more along the window or along the side of the room, or even outside this point, light is still gonna be casting photons out in all directions. And what that means is we're gonna wind up with a lot of wasted photons that are gonna be contributing nothing to the overall illumination. So if we had some kind of a light source out here. We would not want to use a point light has the photo on emission source. In this kind of a situation, we would probably want to use something like a spotlight or an area light. So that way we can actually focus these photons in a particular direction. So if I really use a spotlight in the same exact way that a spotlight is gonna be emitting light in a cone type pattern, it's also going to emit photons in that same conical shaped pattern. So what? This means I could take this spotlight, move it just outside, or align it with my direct light source. And now, instead of wasting a lot of photons on in this direction, all those photons are gonna be concentrated into one direction. All right, so choosing the right type of light that's gonna be casting your photons is going to be very, very important. And again, this is something that's gonna be unique for your particular lighting situation. All right, so now that we've had a chance to talk just very briefly about what these photons are actually gonna be responsible for in our scene and a couple of things you're gonna need to be very aware of when it comes to emitting these photons and you're seen through these individual light sources. Let's now start to talk about in the next lesson how we can take these direct lighting sources and actually tell them to emit thes photons.