Flash has always allowed the use of Active X controls in its interface rollouts, and by using Flash's FS Commands, you can allow interaction in the Flash interface to affect 3dsmax, and 3dsmax interaction to feedback to Flash. It's a really easy way to build rich interfaces within 3dsmax without getting into C++ plugins.
The following demos were all completed from 2002 to 2005 using Flash 4, and its quite basic (by today's standards) scripting language. I can't even remember if it was called ActionScript then, or was just Flash.
Anyway. Needless to say, if you want to do funky Flash interaction these days you should be looking at .net inside 3dsmax and ActionScript 2 / 3 in Flash using ExternalInterface to provide the communication between the two.
Now for the demos…
Axis Control Demo
This demo basically demonstrates a frame-loop running inside Flash that allows you to drag a joystick-like button to control the animation of a selected object in 3dsmax.
It's really interesting to see an object react in realtime in the max viewport, and you can set animation mode on, then play the timeline to record the movement as well.
This demo shows 2-way communication. The demo maxscript animates a ball, then sends the coordinates to Flash. You can also click the radio buttons to show another view in Flash, and in Flash, click the animation key indicators to start the 3dsmax timeline playing from that point.
It's interesting to compare the actual trajectory in the max viewports with the Flash app. With a little more thought I'm sure some cool stuff could be achieved with this, especially now (late 2009) as we now have proper 3D in Flash.
Character UI Demo
Probably the most useful demo of the three, this demo is simply to demonstrate how you could build a custom interface within Flash, then use it to select elements in your scene without having to muck about with selection sets, or the scene explorer. In the real world it would probably be written more flexibly, i.e. with XML files and not hard-coding the element names, but you get the idea.
Note: the demo below is actually interactive.
Download and installation
You can download the demo files here, and start poking around both the 3dsmax and Flash scripts to see how they work.
In 3dsmax you MUST edit the path to the swf file in each of the scripts before you run them, or else they simply won't work, or you will get errors.
Lastly – as I said at the top, this would certainly NOT be the way to do it today! But it's interesting to think that this sort of thing could be done 7 years ago. Did anyone take advantage of it? Not to my knowledge which is a real shame I think.
If I was still a 3dsmax TD today, I imagine I would be doing this sort of stuff all the time!