Introduction
In Part 1 of this guide (Interface and Tools), we took a Box primitive with 8 x 8 x 8 segmentation from the Scene Editor to the Advanced Modeler, converted it from a primitive object to an editable mesh, and had a detailed tour of the Swift 3D Advanced Modeler interface. If you are unfamiliar with the Swift 3D Advanced Modeler interface, then please read Part 1 before proceeding with this guide.
During the interface tour in Part 1, there were two terms that I glossed over: Surface Groups and Smoothing Groups. Here in Part 2 of this guide, we will explore Surface Groups in depth, and learn how to work with them effectively in Swift 3D modelling projects.
Surface Groups: Definition
In the Properties Panel on the left side of the Advanced Modeler interface, the third item in the menu list is Surface Groups. A Surface Group is a group of one or more faces that have been assigned together as one unit. While the faces remain separate and can be transformed individually, they can also be selected and edited as a group using the Surface Group selection tool. Using Surface Groups wisely is an integral part of any Swift 3D project. It gives you the ability to apply multiple materials and textures to one object, and is a fast and easy way to select large groups of faces that need to be moved or transformed together.
The Surface Groups page of the Properties Panel displays a list of all of the Surface Groups in your model, and when one is selected in the list, the buttons below it can be used to Select it in the workspace, Hide it in the workspace, or Show it if it's hidden. The fourth button, Group Selection, will group whatever faces you have selected in the workspace into a Surface Group.
The Material subsection below the Group Selection button will display the material that is currently assigned to the selected Surface Group.
Exercise 1: Create a Box Mesh in the Advanced Modeler
Let's use Surface Groups to apply six different colored materials to a box. If you have the 8 x 8 x 8 box mesh from Part 1 of this guide, delete it. In the Toolbar (top), choose the Create Box Mesh tool.
When you click on the Create Box Mesh tool, the Properties Panel on the left adds a new page called Box and jumps to that page.
This is your one and only chance to modify the segmentation of the box before creating it as an editable mesh in the Advanced Modeler workspace. Once you create the box as an editable mesh, all object-level properties are no longer editable. For now, though, let's leave the segmentation at 1 x 1 x 1.
Move your mouse over to the center of the Perspective Viewport, hold down CTRL, Click and Drag up and to the left. When the Box mesh looks like a good size to you, let go of the mouse button and the CTRL key.
You've just created a Box mesh in the Advanced Modeler interface. Sweet. Now let's use Surface Groups to apply six different colored materials to this box. In the Toolbar, choose the Face Selection tool.
In the Perspective Viewport, click out in the empty space somewhere to deselect everything. Now use the Face Selection tool to select the two faces of this box that are closest to the Camera, by clicking on them one at a time.
With those two faces selected, Right-Click (or CTRL-Click on a Mac) to get the Viewport Context Menu, and choose Group > Selection.
Now those two faces are their own Surface Group. The other option in that context menu, And Separate Selection, will group the selected faces into a Surface Group and detach them from the rest of the mesh. That function serves its purpose in some cases, but not right now.
To create the other five Surface Groups, select the other sides of the box one at a time, and repeat the Right-Click (or CTRL-Click on a Mac), Group > Selection process for each side. Hold down ALT to rotate the Camera angle as needed so that you can select each side of the box. When you've completed making all six Surface Groups, take a look at the Surface Groups Page of the Properties Panel (left side of the interface).
As you can see, there are now six Surface Groups in the list. Swift 3D's default naming convention for Surface Groups is that the first group will retain the original name from when the mesh was first created, and all subsequent groups will be named Regroup0x in one-up order. If you want to change the names of your Surface Groups, you can do so with the the text input box just below the list. Just type in the new name and hit Enter.
Applying Materials to Surface Groups in the Advanced Modeler
In the bottom-right area of the Advanced Modeler is the same menu panel that appears in the Scene Editor. The exception is that in the Advanced Modeler, only the Materials and Models options are available. This is a modelling environment, not a scene building environment, so the Animations, Lighting, Environments, and Bevels cannot be used here.
Using the same method as what you'd do in the Scene Editor, drag a new material onto one of the sides of the box.
Notice that the material is only applied to the Surface Group where you dropped it. As you can see, creating Surface Groups in the Advanced Modeler is the way that you apply multiple materials to the same object in Swift 3D. Just for fun, I dragged some loud colors onto all of the sides of the box, and rendered this result:
The important point to take from this part of the Advanced Modeler Guide is this: in any case where you want to put multiple materials onto one object, the way to do that is to take the object into the Advanced Modeler, and use Surface Groups to define the parts of the object where you want each material to be placed.
Surface Groups are also very handy for grouping and naming the different parts of a mesh as if they were parts of a real object. For example, if you were contstructing a model of a car in Swift 3D, you might have a bunch of Surface Groups with names like Front Tires, Back Tires, Body, Windshield, Left Windows, Right Windows, Back Window, etc.