Welcome to the second part of my sub-surface scattering guide for 3dsMax and mental ray. In this epic tutorial we’re looking at how you can use mental ray’s Sub-Surface Scattering (SSS) tools in order to make your renders more realistic. This technique is often misused, misunderstood, and- if implemented wrong- can seriously affect your render times. After reading this tutorial you’ll walk away with a broad understanding of both the concepts behind SSS and how to implement it effectively in 3d Studio Max and mental ray.

Just like before, I’ll be explaining things from the perspective of a beginner/intermediate user.  You should know what mental ray is, how to enable it, and how to create new materials.  I’ll provide you with downloadable source files along the way so you can have a starting point for any complex effects.  I strongly recommend that you at least glance over the first part of this  SSS guide in order to make sure you have a strong understanding of the basic concepts before tackling this second section.

Remember that this guide is geared toward discussing what options are available in the 3dsMax implementation of mental ray, followed by detailed guidance on each material and shader type.  Toward the end of this section we’ll put these concepts into practice by manipulating renders step-by-step.

In part 1 of this tutorial we discussed

• What is Sub-Surface Scattering,
• The Fast SSS Material Type, and
• The Fast SSS Skin Material.

Then, in Part 2 of this tutorial we’ll discuss

• The SSS Physical Material & Shader, and
• The Parti-Volume Shader.

You can download my starter scene here, though I’m not including the texture files because they’re copyrighted so you may get an error message.  Any complex materials I create will be provided through a scene file, too.

In this epic tutorial we’re going to take a deep look at how you can use mental ray’s Sub-Surface Scattering (SSS) tools in order to make your renders more realistic.  This technique is often misused, misunderstood, and- if implemented wrong- can seriously affect your render times.  After reading this tutorial you’ll walk away with a broad understanding of both the concepts behind SSS and how to implement it effectively in 3d Studio Max and mental ray.

SSS via parti-volume shader (Part 2)

I’ll be explaining things from the perspective of a beginner/intermediate user.  You should know what mental ray is, how to enable it, and how to create new materials.  I’ll provide you with downloadable source files along the way so you can have a starting point.

We’ll begin by getting a strong understanding of what options are available in the 3dsMax implementation of mental ray, followed by detailed guidance on each material and shader type.  Finally we’ll put these concepts into practice by manipulating renders step-by-step.

In part 1 of this tutorial we’ll discuss

• What is Sub-Surface Scattering,
• The Fast SSS Material Type, and
• The Fast SSS Skin Material.

Then, in Part 2 of this tutorial we’ll discuss

• The SSS Physical Material & Shader, and
• The Parti-Volume Shader.

You can download my starter scene here, though I’m not including the texture files because they’re copyrighted so you may get an error message.  Any complex materials I create will be provided through a scene file, too.

This is the starter scene file for the sub-surface scattering tutorial that’s going up tomorrow (part 1 at least).  You can download this file and get immediate results.  The material I’m using is the default SSS Fast Material with the following changes:

• Turn on “Advanced options” > “Scatter indirect illumination”.
• Turn off “Advanced options” > “‘screen’ (soft) compositing of layers”.
• “Advanced options” > “scale conversion factor” is 0.3

Consider rendering this with the Free High-Res HDRI Pack I’ve posted.

As I’m working on the new Sub-Surface Scattering tutorial I thought I would break off a small piece and make it an independent post. Below I’ll provide a visual guide to the parameters in the 3d Displacement Shader in 3d Studio Max mental ray. It’s pretty straightforward but there are some interesting things you might not have known you can do with it!

The 3d Displacement Shader Controls

Object Independent

When this is turned on the displacement effect is independent of the size of the object’s bounding box. When it’s off the displacement effect is scaled according to the size of the object.  Scaling the displacement based on object size is the standard behavior for regular 3ds Max displacement mapping so if you leave this checkbox checked then the displacement length will behave like a normal material would.

Left has Object Independent enabled. Right does not.

Displacement Length

This is the length of displacement when Object Independent is checked, the extrusion map is at 100 percent (white), and the Extrusion Strength equals 1.0. Lower gray levels in the extrusion map, or other values of Extrusion Strength, scale the amount of displacement.  Think of this as a way to alter the displacement map’s contrast.

0.083 (default), .25, and .35 displacement lengths

Extrusion Strength

Controls the height of the displacement. This value is a multiplier: at the default value of 1.0, the map’s effect is unchanged. Greater values will make the displacement more severe while lower values will make it more subtle.

1, .5, and 1.5 extrusion strengths

Extrusion Map

Click to display the Material/Map Browser and choose a map to use for the displacement. Displacement maps apply the gray scale of the map to generate the displacement. Lighter colors in the 2D image push outward more strongly than darker colors, resulting in a 3D displacement of the geometry.

Checker map, dent map, marble map

Direction Strength

Controls the strength of the direction shader.  Adding a direction shader has no real effect unless you have the Direction Strength set above zero.

0, 1, and 2 direction strength values

Direction Map

The direction map is a lot like a normal map.  The direction of the displacement is changed according to the RGB values of the map you use here. Red values offset in the U axis, Green values offset in V, and Blue values offset in W (using the object-local UVW coordinates).

Checker patterns, Red/Green, Red/Blue, Green/Blue

I bet you wern’t expecting this on a Thursday. This Monday Movie fills in the gap that came up when I was really sick that one weekend and couldn’t make a Monday Movie. In this video, we’ll look at how you can use the Parti Volume shader in mental ray to quickly create mist or volumetric lighting effects. It’s surprisingly easy to use once you know what spinners to mess with- but be careful! It can cause high render times!