Getting 2D screen coordinates of a 3D object in Papervision 2.0

How do I get the 2D screen coordinates of a 3D object when using Papervision 2.0 (Great White)? I've read that following properties should return the screen coords but these always return 0.

myDisplayObject3D.screen.x
myDisplayObject3D.screen.y

I've also tried setting:

myDisplayObject3D.autoCalcScreenCoords = true;

Bu开发者_Python百科t this has no effect. Any help would be appreciated.

Turns out I was attempting to read the values immediately after adding the object to the scene but BEFORE the renderers next render cycle. I added the above code to my enter frame listener and all subsequent traces worked correctly.

screen.x and screen.y should work. Is your 3d object added to the scene ?

In the online articles(pv3d.org, everydayflash) all looks fine.

Could you post a snippet ( either isolate the bit of code, either write a simple analogy to your situation) so we can get a clue of what might be wrong ?