While Swift 3D does do a better job with file sizes than other applications, sometimes, the file sizes for simply 3D events can become so astronomical. Usually any animation over 30k that doesn't include sounds, movies, etc. isn't appropriate for web publishing. For example, a spinning logo of "kirupa.com" takes over 140k to Display. Below are the various answers to compression, etc. that people have been having.

This example is mainly just theoretical. So, there's no need to have a source code downloaded. 

Once you have finished your animation, it's time to Export your file to the SWF format. Go to File > Export. You should be presented with a window with information on location, etc. The main screen that we will be dealing with is the "Output Options" area. See image below:

Here's what the various options mean:

• Include Edges
  This is an option for including edges. Usually if you have this checked, you can see some distinct lines in your animation. Most of the time, the lines contrast with the animation too much and should be avoided if possible.
   
• Outlines
  This box becomes visible when the Include Edges button is selected. This simply creates primary lines that highlight your animation. Again, this option need not be used for most situations.
   
• Entire Mesh
  The Entire Mesh option shows the line of every single polygon in your animation. While the animation may look a little more distinct, the file size usually increases dramatically.
   
• Fill Objects
  Specifies whether your objects will have a fill (color, texture) applied to them.
   
• Flat Filled
  This option is nothing more than a few colors blotted onto the animation. The quality isn't impressive on bit, and the "3D" feel is gone completely.
   
• Area Shading
  This is the best option to use for filling in of objects with complex details. The file size is acceptable for most instances. This option provides the best balance of quality and size.
   
• Mesh Shading
  This option provides almost realistic shading, lighting, effects. So, why isn't this option recommended over others? The file size literally balloons exponentially when this option is checked.

The above list provided a brief overview of the various Exporting Options available. For best performance/size, it is best to NOT include edges. For the filling in of objects, I recommend using the Area Shading option. Of course, your needs will vary according to the type of animation you are performing. Experimenting with different formats is the best option.

Just a final word before we wrap up. If you have a question and/or want to be part of a friendly, collaborative community of over 220k other developers like yourself, post on the forums for a quick response!