Caustics in MentalRay for Maya

Before we start with tutorial please download the scenes that we will use in our training.

DOWNLOAD THE SCENES

INTRODUCTION

So we meet again (for those who passed through my GI tutorial ;) ). This time we will learn how to set the caustic effect in mentalray for maya. As you already know, the calculation of caustics is not integrated in maya default renderer, and since we have lot's bottles and liquids in our scene, we just need those little bright areas called caustics. ;)

So, let's go to work. For those of you who have not used mentalray for maya yet, please go to the alias wavefront web site and dl it. It is free. If you want to know how to install it, there is explanation in my first tutorial ... link!

In this tutorial we will explore the mentalray's world of caustics. For our test scenes we will use three type of scene. The first one will be well known caustics example ... glass with water in it. The second one is caustics produced by the sea surface and the third one is just a few simple objects with reflective surfaces. Since caustics take some time to render, except maya and mentalray you will need lot's of patience when going trough this tuto. I'm joking, it render very fast. ;)Yes, you can also fake the caustics and achieve faster renders times, but you will not get the real caustic effect, and it can be a little problematic when it comes to moving lights or objects that produces caustic effect in the scene.

Let's take a look at a few real time examples and say a few words about him. This was shoot with my new digital camera... yuppi! ;)

Real world examples:

 

Caustics are marked with red lines on both pictures. In our first example of this tutorial we will try to make the caustics similar to the one in first picture. These two examples show two different kind of caustic effect. On the first pic the caustic are produced by refraction of the glass and the water inside, and on the second one by the reflection of the cd. When the light ray passes trough the glass and the water it changes the direction, this is called refraction. Because of cylindrical shape of glass, the light rays are refracted in that way that they become accumulated together when they exit the glass, and after they hit the desk, the part of it gets brightly illuminated... that is called the caustics. On the second example, the reflection of the CD object is guilty for the caustic effect on the paper below it. In this example the light rays are reflected from the CD, and after they hit the paper it gives it an additional illumination, that's why the part of paper surface is brighter than other parts.

 

NEXT > EXAMPLE 1 - The glass with water

 


Toni Bratincevic - toni@interstation3d.com - http://www.interstation3d.com