Going crazy over something so simple!!!…….Arrows on a Z-axis

[Darby Edelen]

[Martin Banks] “which I want to animate along the Z-axis so they come from behind and straight towards the camera until they are no longer visable due to being the other side of the cam.”

I’m not entirely clear on what the problem is.

[Martin Banks] “The problem I am having is that the arrows always end up coming of the side of the comp, even if I make it wider.”

If I understand what you’re doing then it doesn’t really surprise me that they go off the sides of the composition. 3D coordinates are being represented on a 2D plane (the screen) and so need to be projected. The general function for projection is:

x2D = x / z * zoom;
y2D = y / z * zoom;

So at a theoretical z value of 0 where the layer is at the exact same plane as the camera (all of these values are relative to the camera position) your 2D x and y coordinates are infinite. As z approaches 0 your 2D x and y values will always approach infinity (off the side of the screen).

What I’m saying is, if your 3D layer isn’t in the exact center of the screen, as you move it closer to the camera it will always move toward one edge of the screen. Which edge that is will be determined by the 3D x and y values relative to the camera. If the layer is on the left side of the camera then the layer will move toward the left edge of the screen, if it’s below the camera then it will move toward the bottom edge of the screen, etc.

Does this clarify? Have I missed the point/problem?

Darby Edelen

NVIDIA
Santa Clara, CA

[Dan Ebberts]

Have you tried turning on the Collapse Transformations switch for the inner comp layer in the outer comp? That should keep things from getting cut off in the outer comp.

Dan