RFAQ:Animation: Orthogonal to the Camera

Q: I remember in 3ds r4 there was a (keyscript?) that kept 2D objects perpendicular to a camera. Is there anything similar to this in MAX?

A: My first answer was - use an expression, but I was wrong.
Actually this turned out to be one of the easiest tasks to control in MAX!

Create a 2D Shape in the Front Viewport.
Create a Camera.
Create a Dummy and Allign to the center/bottom of the 2D Shape.
Allign the Camera's X coordinate to the 2D Shape.
Open the Track View, select the Transform track and add a "Look At" Controller.
Open the Motion/Parameter menu.
Select the Dummy, in the Motion menu click "Pick Target" and select the Camera.
Link the 2D Shape to the Parent Dummy. Bacause the Camera is alligned to the 2D Shape/Dummy system, the Shape should still be perpendicular to the Camera.
In the Hierarchy/Link Info menu uncheck "Inherit Rotate" for X and Y of the Shape.
Now you may Animate the Camera as you wish - the 2D Shape will always remain perpendicular to it.
Select the Shape/Dummy system and clone as instances - for example to create a forest. You can map any of the instanced Shapes with a tree map...