Quick Material Assignment Tutorial

Chronology of a 3D model without material, with material, and rendered

Introduction

This tutorial will cover basic material assignment in Autodesk Maya. With a few steps you can assign materials to your 3D model, to distinguish between different elements in the model, and to make it look more interesting and communicative on renders.

An example of a 3D model with only shaders used, no textures.

For clearness' sake, when we are discussing the term 'materials' we are actually referring to 'shaders', which is the appropriate term used in computer graphics to describe the visual appearance of an object. On the other hand we have textures. Textures can be images of photos from a material (I.E. a brick wall), which you assign to a shader, to create an certain effect on your shader. This tutorial will only cover the making and assignment of shaders (in our case colors and physical quality like reflectivity), for more information on textures and a more in depth documentation materials in Maya, see the Materials and textures

Getting started

Before you can assign materials to your geometry, you first need to create new materials. This is done in a part of Maya that is called the Hypershade, besides materials it also contains information about lights, textures and camera's, but for now we will focus on materials.

Go to Window > Rendering Editors > Hypershade

When you open the Hypershade, by default you will see some spheres on the left, and two windows on the right. The spheres on the left represent the different maya-materials you can create. The Maya-materials are now obsolete, because Mental Ray is the renderer of choice. Mental Ray materials will be used in this tutorial. We will switch to the Mental Ray materials in short notice.

The two windows on the right are, at the top, your material library (which will show all your materials) and the work area at the bottom. For now we will only use the top window, the library. Here we can view, select and alter our materials. In these windows you will also see a preview of what the material will look like (color, transparency, reflectivity).

You will see that there are 3 default materials already present. Amongst them is lambert1, the material all new geometry gets assigned when it is created. Never change the lambert1 material, as it may cause undesired effects.

To start making Mental Ray materials we have to switch the window on the left to 'Mental Ray Nodes' instead of 'Maya Nodes'. Click and hold the 'create Maya Nodes' button and choose 'Create Mental Ray Nodes'. A new list appears. Click the top item called 'materials' to show the list of mental ray materials.

For architectural purposes 'mia_material_x' can create almost any material. Create a new material by left clicking the sphere in the left menu with the name mia_material_x. This will create a new material, which will show up in your material library in the topright window (and also in the bottom window, the work area, but we will leave it as is for now).

Changing Materials

If you double click on a material, the material attribute editor will show up. This is the place to change all the settings of the material. if you double click on a newly created mia_material_x, the attribute editor will look like:

You will see a lot of settings, which for now, for the most part, are not relevant. The ones that are, are the name, color, transparency and the refelectivity of the selected material

• Name, it is not uncommon to have a lot of materials. Therefore it is smart to assign a name to the material you are currently editting, like "glass" or "brick"
• Color, if you double click on the grey-colored square you will be able to select a new color in a color picker menu. Hit accept to set the new color
• Transparency, move the slider to to change the transparency of the material. See the small preview icon at the top of the attribute editor to see its effect
• Reflectivity, the default value of 0.6 is rather high, almost mirror like. Lower it to 0.3-0.1 depending on what you want

Obviously according to the properties of the real-life materials (brick, wood, water, glass etc.) you are trying to simulate, you can change the above settings. Once a material is assigned you can still change the material settings. So feel free to try to the result of changing values.

Assigning materials to your geometry

Now that you have created new materials, you can assign them to elements in your 3D model. First, create some space in the Maya interface so you can clearly view and select object in your viewport. You can change the size of the hypershade-window, or move it around a bit, to get a good view at your viewport.

• Next, select an object, multiple objects or even groups in your viewport.
• Go to your hypershade, right-click on the material you want to assign (keep the mouse button pressed)
• A new menu will pop-up, move the mouse (while holding the rightbutton pressed) towards the top menu that says "assign material to selection", and let go of the mouse
• The selected objects will have the specific material assigned, view the result in the viewport (make sure the viewport is "shaded" by pressing 5 on your keyboard)

In your viewport you can check the model from different angles to see if the assignment of materials went according to your wishes. If you are not satisfied, select objects you want to change, and assign a different material to them.

Assigning materials to faces

It is not uncommon to want to have multiple materials on one geometry. For example, your walls could have a different material on the inside than they do on the outside. Therefore it is possible to give different faces of a geometry different materials. To achieve this do the following:

• Select the object(s) you want to assign different materials to
• Switch to component mode, with face selection (so that you can select separate sides of the geometry)
• Select the desired faces in the viewport by clicking on the small blue square in the middle of a face (hold SHIFT to select multiple faces)
• Go to your hypershade, right click on the material, and choose "assign material to selection"
• The material is now assigned to only the faces you had selected

Finalizing

Now that you have assigned materials to your 3D model you can render it, to make images to use on a poster for example. There are several methods in Maya to create a render from your 3D model, with Vector rendering (left image) or MR Using the Physical Sun and Sky environment (right image)

Some final notes on materials; if you are not content with a material you assigned to your geometry, you can override it by assigning another material. If you want to clean up your hypershade, by removing unused materials, you can easily single-click an already made material and press delete on your keyboard.