The villa includes doors and windows. These objects use multiple material IDs to enable you to apply different materials to different surfaces of the object. (Some other architectural objects, and even some primitives, use the same method.)

A material ID is simply an ID number associated with certain surfaces on an object. It works with the Multi/Sub-Object material. The Multi/Sub-Object material contains multiple sub-materials, each of them linked by material ID to the object that uses the Multi/Sub-Object material.

Doors and windows use material IDs in the same general way, as shown in the following illustration.

In this lesson, although doors and windows employ five different ID values, you use only two sub-materials: a solid color for the wooden parts, and a transparent material for the glazing or glass panel, which corresponds to the “inner bevel” ID.

Set up the lesson:

• Continue from the previous lesson, or open med_villa_mat_multisub.max.

Create the top-level multi/sub-object material:

1. In the Slate Material Editor, drag a Multi/Sub-Object material from the Browser into the active View, and drop it to the right of the nodes that are already in the View.
   NoteUnlike the Arch & Design and Autodesk materials, the Multi/Sub-Object material is in the Materials Standard group.
   

   A Multi/Sub-Object material is just a container for other materials. By default, there are 10 sub-materials.

   
2. Double-click the Multi/Sub-Object material node so you can see its parameters. Name this material Doors & Windows.
3. On the Multi/Sub-Object Basic Parameters rollout, click Set Number.
   

   In the small dialog that opens, reduce the number of sub-materials to 5, and then click OK.

   

   Now the rollout shows only five sub-materials, and so does the material node, which now looks more manageable.

   

Add the solid sub-materials:

For the solid parts of the doors and windows, you can use the same blue material you used for the railings of the deck and the house.

• Wire the Blue Railings material node to sub-materials (1), (2), (4), and (5) of the Doors & Windows material.
  

  That leaves only ID 3, the inner bevel, which requires glazing.

Add the glazing sub-material:

For the glazed parts of the doors and windows, you need a different sub-material that is transparent.

1. From the Browser, drag an Autodesk Glazing material (Materials mental ray group) into the active View, and wire it to sub-material (3) of the Doors & Windows material.
   
2. Double-click the new Glazing node so you can see its parameters.
   

   The default color is Clear, which is what we want, so leave these settings unchanged.

Select the doors and windows, and apply the material:

1. If the Layers toolbar isn’t visible, right-click the gray area to the right of the main toolbar, and choose Layers to display this toolbar.
2. On the Layers toolbar, open the drop-down list of layers and choose Doors & Windows, then click (Select Objects In Current Layer).

   This selects all the doors and windows in the house.

3. On the Slate Material Editor toolbar, click (Assign Material To Selection).

   This applies the Multi/Sub-Object material to doors and windows: The frames turn blue, while the glazed parts (“inner bevels”) turn transparent.

4. Right-click the Camera-Terrace viewport to make it active, and then on the main toolbar click (Render Production).

   3ds Max Design renders the scene.

   

   Incidentally, in this rendering you can see a small amount of the interior wall paint that you created in the previous lesson.

Save your work:

• Save the scene as my_villa_doors_and_windows.max.