Flash Tutorials

Introduction

During the Advanced Modeler interface and tools tutorial in Part 1, there were two terms that I glossed over: Surface Groups and Smoothing Groups. In Part 2, we explored Surface Groups in depth and learned how to create them in the Advanced Modeler.

Here in Part 3, we are going to explore Smoothing Groups in depth, and learn how to use them effectively in Swift 3D projects.

Smoothing Groups: Definition

Smoothing groups are similar to Surface Groups in that they define render settings for certain areas of a mesh. The difference is that while a Surface Group defines a material or texture, a Smoothing Group defines an area that will be shaded evenly, with no discernable border between adjacent faces.

Smoothing Groups, used in conjunction with some of the other subdivision smoothing tools in the Advanced Modeler, can produce effects that are similar to - though much less powerful than - the HyperNURBs tools that you’d see in high-end 3D applications.

How to Access Smoothing Groups

If you still have your practice file from Part 2, with the box mesh that we divided into six Surface Groups, then keep it open. Otherwise, head into the Advanced Modeler and create a box mesh in the Perspective Viewport.

Smoothing Groups are a feature that can only be accessed while in Edit Mesh Mode in the Advanced Modeler. Smoothing Groups are groups of faces, similar to Surface Groups. Basically what a Smoothing Group does is remove the hard edges between the faces within the group.

This has two major effects. First, when rendering vector output with Area Gradient Shading or Mesh Gradient Shading or when rendering raster output, any area of the model that is assigned as a Smoothing Group will have a consistent, smooth appearance.

Second, when rendering vector output with Outlines, any area of the model that is assigned as a Smoothing Group will not have any outlines within it, only around its outermost edges. There is one exception to this, though. When a Smoothing Group crosses over multiple Surface Groups, then there will still be outlines at the edges where those Surface Groups meet.

Creating and Deleting Smoothing Groups

To begin working with Smoothing Groups, go to the Smoothing Groups page of the Properties Panel and click the Unsmooth All button. Now this box mesh has no Smoothing Groups at all. Above the number grid in the middle of the panel, click the Assign button. Now we're in Assign mode for Smoothing Groups. Let's create one.

Choose the Face Selection tool, and in the Perspective Viewport, select the two faces closest to the camera by clicking on them one at a time.

Now over on the Smoothing Groups page of the Properties Panel and click the 1 button in the number grid.

What you've just done is assigned these two faces as Smoothing Group 1. Now the edge that separates these two faces is no longer a hard edge. When rendered in vector mode with Area Gradient Shading or Mesh Gradient Shading or in raster mode, they will have a smoothed appearance. Additionally, if you render this box with Outlines turned on, there will not be an outline between these two faces.

As you can see, using Smoothing Groups wisely is a great way to control the appearance of Outlines when rendering cartoon-shaded vector output. Smoothing Groups are also useful when producing raster output, but the name of the game with Swift 3D is vector animation for Flash movies, and that is where the features of the Advanced Modeler are the strongest.

Now let's look at an example where we combine Smoothing Groups and Surface Groups to gain very precise control over the appearance of vector outlines. Head over to the Properties Panel, select the Smoothing Groups page, and press the Unsmooth All button to erase the Smoothing Group we made earlier.

Using the Face Selection tool, select the two faces that are closest to the camera and the two faces next to those. Now you have two sides of the box selected. Just like we did in Part 2 of this guide, Right-Click on the selection and choose Group > Selection from the context menu.

Now these four faces are one Surface Group. Using the Surface Group Selection tool, select this Surface Group. Go to the Smoothing Groups page of the Properties Panel, and assign this Surface Group as Smoothing Group 1.

See the below screenshot to view the effect this combined effect has on rendering.

Conclusion

Seeing this effect demonstrated with a simple box outline isn't all that impressive, but it definitely makes the wheels turn when you think about the possibilities of applying complex “paint jobs” to sophisticated meshes that will be rendered for vector output with outlines. It looks particularly impressive when it's in motion. Swift 3D is primarily a 3D vector animation tool, afterall.

Now that you have a fundamental understanding of the Advanced Modeler interface, Surface Groups, and Smoothing Groups, the next step is to get your hands dirty with some modelling projects. The later parts of this guide will be hands-on exercises in which we will model and render complex meshes in Swift 3D. See you there!