In 3dsmax7 Mental Ray 3.3 gained a new shader called “Ambient / Reflective Occlusion” what can this be used for? Well, traditionally within Mental Ray GI has been handled photon mapping and Final Gather. In this case a GI effect can be generated via a shader, and in this way this system opens up some flexibility in how you generate your GI.

So what does this shader do? Quite simply it shoots out rays from the pixel that is being shaded in a hemisphere based on the normal of the pixel. It then traces these rays to the scene bounds or to a fixed distance defined in the shader and if it hits a piece of geometry the ray is flagged as occluded. Mental Ray then works out the average number of rays that were occluded and uses this to work out a blend colour between the BRIGHT and DARK values setup in your shader. On the right is a diagram of a typical pixel being shaded.

In the example shown you can see that our shader has thrown out a total of 5 rays. If the BRIGHT colour were white, and the DARK colour Black, we would have two DARK rays and three LIGHT rays. So our pixel would be shaded as 40% occluded, or in other words a grey of 40% black would be used. Due to the way Monti-Carlo sampling works, 5 rays would not give us a very good average, pretty much in the same way as a sampling of 5 people in a survey would not give a very good average opinion of Mr man in the street. So for a better quality render you would expect to use 24+ samples.

goto Tut0rial :

http://www.christopher-thomas.net/pages/free_tutorials/tut_ambient_occlusion_shader/ct_tut_mentalray_ambientocclusion_shader.htm

This tutorial used Maya 8.5 for the modeling, MentalRay for rendering, Photoshop for creating the textures and Shave and HairCut for the fur of the head.

Greetings everyone. So I’ve had a number of people approach me here at school about a method I’ve been using to break my Miss_fast_skin_maya subsurface shader into render layers so I have near absolute control of it in compositing, so I though I’d write up a tutorial here to share.
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This tutorial will guide you to achieving a fairly realistic open water effect which can even be animated, using the
‘Ocean’ shader from the Lume Library.

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In rendering of scenes and lighting in general, one of the most complex to achieve the so-called Caustics. This is the dispersion of the ray of light for a semi-transparent surface that allows the passage of photons on his material. One of the easiest ways to give the effect in the real world is to get a cup, with a bit of liquid and place next to a light source. The 3d tools generally do not produce such an effect with the type scaline renderer, with only specialized in raytracing software, such as the V-Ray, Mental Ray or YafRay. For example, in Blender 3d is possible to simulate the effect, using the YafRay.

But with the Mental Ray?  If you are a member of 3DS Max, but still does not know to use the tool to generate Caustics with the 3ds Max, a very simple tutorial, shows the steps necessary to establish the effect of so quickly. Despite being at an accelerating pace, after seeing the video, you can reproduce the effect without major problems.

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At the time of He has lectured on the 3ds Max, always commented to my students a curious fact in relation to the use of external rendering to the Max After the Mental Ray is now integrated with the software as a way of encouraging their Autodesk use, was somewhat meaningless the addition of other renderer as the V-Ray or Final Render, as in virtually all respects the Mental Ray meet the needs of artists, with advanced options of Ray Tracing and lighting overall.

But this time the Autodesk failed to convince many people on the mass adoption of the renderer. Why not? Simple to learn just ask any artist what he thinks of Mental Ray and most will say that the learning curve it is very long. This means that you need much practice and study in order to effectively dominate the software, so he still finds strength in artists who need speed and speed in rendering solutions.

For people who are still learning the operation of Mental Ray, and want to start doing some tests with the software, I found a very interesting and simple tutorial, which also uses one of the scenes that accompany the 3ds Max This tutorial shows the configuration of global illumination, using a single point of light in this case a light-type Omni.

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