So I'm working on this little logo fly-by animation. An Entertainment Tonight type of thing. Do a low, close fly over, then pull back and up until the logo is centered in the frame. I set the motion on my camera to motion path. Drew a line across the top of the logo, extended it into a curve up over the center of the logo. Moved the current frame to the center of my animation, put the motion path progress at about half way. Now to take care of aiming the camera: Go to the center key frame. Attempt to change the rotation on the camera using the rotation tool. Nothing. Hmmm... Try to enter the value directly. What!? The camera jumps to the beginning of the motion path? And thus began a wrestling match with Motion Paths that I've finally given up on. The primary issue seems to be that transforms are applied to the camera, but no transform key frames appear in the timeline. If I close and re-open the .car file, the key frames appear. Then the camera started jumping to the end of the motion path in the middle of the animation even though it was set to be in the center. Aarrgh!!! Anyone else have nightmares using motion paths? It really just seems so totally broken I can't understand what's happening. - Jasen.

Motion Paths are one of the coolest things in Carrara but they do cause a little brain damage the first couple of times you use them.

Here are a couple of rules that MUST be followed:
A) adjustments to the motion paths themselves should only be done on frame one of the animation
B) unless you want the camera to face along the actual path of travel, smooth camera tracking should use Target Helper Objects with "Constrain movement along path" deselected in the motion path options. (I think this is what was giving you fits when you tried to readjust the camera position)

Now, here is a "best method" for setting up motion paths:

1. Key frame your camera movement through animiation timeline. Simply move the playhead and reposition the camera where you want it -don't worry about which way it is facing. The key frames will be added automatically.

2. Return the playhead to Frame 1 of the animation select the camera and convert it's motion from Explicit to Motion Path.

3. With the camera still selected and the playhead on Frame 1, use the motion path bezier drawing tools to readjust the smoothness of the motion path.

4. Deselect the "Constrain movement along path" option in the camera motion path window.

5. While still in Frame 1 insert a Target helper object and position it where you want the camera to initially point. Select the Camera and under the Modifier tab, chose the Point At modifier and select the Target Helper Object (THO) as the target.

6. Now, you can start moving the play head through the timeline and move the THO to where you want the Camera to point.

7. The last step is do a little Tweening. I ususally tween the camera motion between the first and second key frames with a bezier option and ease-out the movement of the camera so you don't get whiplash when the animation starts. Same for the tween between the last Key Fame and next-to-last Key Frame.

You can tween the motion of the THO in similar fashion. Using THO's for camera tracking takes the headache out of finessing the camera motion itself and accelerates the animation building process tremendously.

Mark

Message edited on: 03/01/2006 07:03

Thanks. Glad to see that MPs are a bit wonky. Err... or at least that other users agree they are, too. I did a search on the message board and I see this topic has bitten others. I solved my problem a bit differently. I created a helper object that provided the movement/translation (not rotation). I made the camera track the motion of this object - but not the rotation. Then I went back and keyframed the rotation of the camera. I may try a "Point At" helper and see how things go that way. The issue appears to be rotation in Motion Paths. I tried doing some rotation on my target object and it went all wacko, too. It would race to the end of the MP and then go through the rotation. It could be as you say that I was not doing some adjustments related to the MP at frame 1 and this caused unexpected side effects. It still seems broke to me, though. - Jasen.

When you make a transform of the camera, or helper object, that is using a motion path, you are actually adjusting the motion path... NOT the object. So when you rotate the object, the motion path rotates at that time on the timeline. It IS a bit wonky... but has logic too... as long as you follow IT'S logic, instead of your own! ;) I agree with Mark. Setup your keyframes, then convert and use a 'Point at' modifier for best results. Good luck!