3D cameras...
by Cal Johnson
on
Jun 22, 2007 at 5:16:19 pm
Hi everyone. I'm trying to animate a camera in 3D space in After Effects 7. Please note, I'm not new to After Effects, and I use 3D animation software occasionally, so I understand about 3D space.
The movement I am trying to accomplish is to fly the camera in front of a graphic. Its a chart, and I want to show different parts of the chart by moving in close, then backing out and moving in close to another section etc.
No matter what I try, I always get weird wiggling between camera movements. I'll set a keyframe for point of interest and position, then do a simple dolly in move, set a keyframe for POI and Position again, play the animation back, no problem. Then I move ahead in time, position the camera up at an angle, set a third set of key frames for each property, now my animation is wiggling around right at the beginning.
I've tried working with the orient to to path, set the POI to off, using a null object to parent the POI of the camera to, nothing allows me to make smooth motion without weird wiggles in between.
I've used three different 3D sofware packages, and none of them have this issue. I am able to move the camera smoothly from one position to another. I can move the camera both in space, and in 3 axis movement in relation to itself. It works just like a camera would in the real world. What really stumps me is that I start the animation in After Effects, and its going fine, then at some point the whole animation goes wonky, which doesn't make sense to me as I'm not changing the values of the previous keyframes I set.
I've gone on-line to vtc and watched tutorials, plus I have Creating Motion Graphics in After Effects. The next thing I'm going to do is pre-compose all my layers, and animate the precomp leaving the camera static. I'd sure like to know how to aniimate the camera properly though. It seems like its only good for moving from point A to point B, or doing wild crazy fly-throughs where you don't really care about precise camera movement or orientation. In my other 3D aps I can ease the camera from one position to another without issue. I realize After Effects isn't true 3d, but don't understand why the camera can't work like a normal 3D camera would. Any help would be appreciated.
Re: 3D cameras... by Darby Edelen on Jun 22, 2007 at 5:40:59 pm
It sounds like your the Spatial Interpolation of your keyframes is set to Auto-Bezier. Try setting them to Linear, select them all, right click and select Keyframe Interpolation.
There's also an option in Preferences>General to default spatial interpolation to linear. I swear by this little checkbox because more often then not I want a straight line, and when I don't I prefer to go in myself and alter the bezier handles.
Darby Edelen DVD Menu Artist Left Coast Digital Aptos, CA
Re: 3D cameras... by jwessler on Jun 22, 2007 at 6:44:05 pm
Cal,
I agree that the problem is likely in the interpretation of your keyframes.
After Effects has this nifty little system built in that will automaticlly create smooth lines between keyframes. If you have two keyframes, there is no need to worry about the interpolation. Once you add that nasty little third keyframe, After Effects now has enough to apply "interpolation." If you zoom in EXTREMELY close on your keyframe, you will notice that your path INTO and OUT OF the keyframe is not straight. You can get a little boomerang effect, especially at endpoints.
Aharon Rabinowitz has two tutorials on this very problem. Check them out here:
I found them both very helpful. You can always do what Darby mentioned above and set your preferences so that ALL new keyframes are added Linearly. Of course, if you like the Auto Bezier and want to turn it off only for selected keyframes, follow his advice and that should work great.
Re: 3D cameras... by bogiesan on Jun 22, 2007 at 7:35:59 pm
> I'll set a keyframe for point of interest and position, then do a simple dolly in move, set a keyframe for POI and Position again, play the animation back, no problem. Then I move ahead in time, position the camera up at an angle, set a third set of key frames for each property, now my animation is wiggling around right at the beginning. <
You cannot use POI and Orientation/rotation keyframes at the same time. AE gets really confused.
Use one or the other or use a null to guide how your camera points.
bogiesan
This is my standard sigfile so do not take it personally: "For crying out loud, read the freakin' manual."
Re: 3D cameras... by Cal Johnson on Jun 22, 2007 at 8:36:04 pm
I'm not using orientation and POI at the same time, I never was. I'm only using position and POI, not orientation or rotation. The keyframes were set to linear. It seems to be an inconsistent problem. Some moves are ok, others go out of wack. What I don't understand is how setting a third linear keyframe effects the camera movement between the first two.
I'll have a look at the graph and see if I can straighten out any issues there. Thanks.
Re: 3D cameras... by Darby Edelen on Jun 22, 2007 at 9:09:21 pm
[Cal Johnson]"What I don't understand is how setting a third linear keyframe effects the camera movement between the first two.
I'll have a look at the graph and see if I can straighten out any issues there. Thanks."
If the keyframes are linear (we're talking spatially here, not temporally) then adding a 3rd keyframe shouldn't effect the camera movement. A keyframe can have linear spatial interpolation and an entirely different kind of temporal interpolation.
The value/speed graphs have nothing to do with spatial interpolation and everything to do with temporal interpolation (i.e. easy-ease/bezier). Temporal interpolation can be seen in the timeline as the keyframe changes shapes depending on whether it's using easy-ease, ease-in, easy-out, bezier or linear temporal interpolation.
What I'm concerned about is your spatial interpolation which does not effect the shape of the keyframe on the timeline at all, to notice spatial interpolation you have to look at your motion path for bezier handles (select the keyframe that's giving you trouble) or right click your keyframe and check the Keyframe Interpolation.
I'm sorry if this is redundant for you, but your wording in your post seemed to be confused about spatial vs. temporal interpolation.
Darby Edelen DVD Menu Artist Left Coast Digital Aptos, CA
Re: 3D cameras... by Cal Johnson on Jun 22, 2007 at 8:53:44 pm
Ok, so I've tried everything, no luck. Here's a fairly straight forward example of what is going on.
At the start of the comp, I enable keyframing for both position and point of interest parameters. I start with a simple camera move, a dolly in towards my graphic. I then want to crane down my graphic to a different section. There is never a point in which I want the camera to crane up, it goes from moving straight towards the graphic to craning down. Yet, there is a weird up & down bobble just before the camera moves down. I've tried adjusting the handles of the motion path, I've tried the graph but it shows linear keyframes.
I'm getting discouraged and starting to wonder if this is just a software limitation. As I mentioned, I do lots of graphics work with 3d aps for logos and such, and this problem never arises. You simply move and position the camera where you want it to be, from one point of the animation to the other.
