- April 6, 2005 at 8:44 am
I have been having some serious problems (I’m sure just because I am missing some obvious step or something), but I need help with the movement of my Camera through my 3D composition.
Here’s the setup:
I make a solid, 200 x 200, and label it “position.” Then, above that, I put in one called “Swivel.” Above that, “Tilt.” Above that, “Distance.” Then I have my camera on top of all that. I parent the camera to the “distance” layer, and the distance layer to the “tilt” layer, then that to the “swivel” layer, and that to the “position layer.” After that, I take it a step further… for the camera movement, I create another solid, above the camera, and add three expression controls… a slider, and two angle controls. I parent that to the camera. After that, I create an expression for the “swivel” layer for the Y rotation, which makes it controlable by the first angle control in the expression controls. Then, I create one for “tilt” on the X Rotation, making it controlable by the second angle control in the expression controls. Finally, I make an expression for scale in the “distance” layer, which controls the scale by the slider control in the expression controls. My logic is this, (and maybe this is where I have gone wrong) Position = Point of Interest, Swivel = Y rotation of camera, Tilt = X rotation of camera, and distance = distance from point of interest.
Sounds good… then I try to fly around with the camera…
It turns out that my point of interest is NOWHERE where I want it, and everytime I adjust anything, particularly the “distance” slider, my point of interest changes drastically. I have figured out how to get it to work fine if I am flying along a plane on the z-axis of the composition, not moving in any circular motion. The problem comes from when I want to fly around an object, circle around, etc. etc.
What do I need to do to keep my point of interest moving with my camera so that it doesn’t get screwed up? I’ve tried animating the position keyframes, but it ends up creating more of a mess than I started with. Is there any way of parenting/writing an expression to solve this? What have you found to be most effective for doing something like this?
Sib Ntsib Dua
- April 6, 2005 at 9:16 am
Point of interest is one of the most annoying things AE’s camera does.
Go to a frame where you are happy with your POI. Create a keyframe for it. Now move to the end of the comp, and paste that keyframe. sometimes, when i’m in a panic, i create POI keyframes for every new camera position keyframe, but i’m sure i don’t need to.
However, i’m no good with expressions, (you seem fairly comfortable with them), i can’t beleive there’s no expression to control POI.
- April 6, 2005 at 1:41 pm
Why not just turn off the point of interest? Select the camera and hit ctrl-alt-o (pc) for auto-orient settings. then select “off”. I will usually then make a null and parent the camera to the null, because I feel i get better control.
Another option is to use an expression and link the POI to a null and animate that.
Director, Digital Post
CCG MetaMedia, Inc.
- April 6, 2005 at 1:49 pm
The Point of Interest can be your best friend if you know how to use it. In AE, you have to think of camera motion in terms of both camera position AND point of interest. With these two parameters alone you can get accurate camera moves without ever having to mess with rotational key frames.
The frustration comes in not knowing how to constrain the point of interest when moving the camera. Holding down the Ctrl key (windows) will lock the point of interest in place while you move your camera. It becomes second nature after a while.
I promised Kathlyn a tutorial on 3D camera motion if I can ever get out of the weeds. Stay tuned.
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