It was great.  I had a moment of triumph.  In my meager 3D and Away3D experience I managed to get face linking functionality into Away3DLite.  Proud of myself, I posted my success at the list.  But my party was soon rained on by one of the Away3D developers, Peter Kapelyan, who immediately informed that my linked objects weren’t aligning as they should be.  It felt a lot like that scene in National Lampoon’s Christmas Vacation where Clark finally gets the lights lit on his house, only to have his father-in-law inform him that the little lights weren’t twinkling…

I know Peter, thanks for noticing.

To that end, the above demo is the next revision of my prior face linking code.  This time, I got alignment working.  Because I am 3D math deficient (I’m working on it) I was unable to implement the alignment properly without using a container object for the source and the linked objects.  Someone a little more math savvy can surely make use of the upAxis parameter of the lookAt() function to make it work, but I need some studying before I can do it on my own.  Shawn McInerney from the dev list offered up a potential solution, but it’s a little over my head now.  Perhaps someone else perusing this blog can make use of it.

I hope Peter didn’t take this the wrong way, as I have an abrasive sense of humor that doesn’t translate well to written word.  Just in case, here’s a link to his site which is extremely clean, cool, slick, and a whole bunch of other adjectives that equal up to awesome.

The above is a demo of face linking implemented in Away3dLite (right lick to view source).  As you’ll see in the demo, face linking allows us to “link” a 3D object to another, rendering it at the center of the source’s face and then moving along the face’s normal by a given offset.  All credit goes to the original author of the Away3D FaceLink class, as my work was just a minimal modification to port it to Away3DLite.

One thing to note is that this demo required a modification to the Face class, found in away3dlite.core.base.Face.  I simply added a calculated normal and center for the face at creation time and made it available as a public variable.  It’s not altogether the cleanest code I’ve written, but it gives you a good idea of how you might use face linking in your own Away3DLite application.

Just for fun, here’s a couple links to other flash apps I’ve seen that make cool use of faces, vertices, and normals:

• EveryDay3D – 3D experiments with Flash Player 10 and AS3Dmod
• Fabrice Closier – Away3D FaceLink