View Full Version : Need Help Animating a Camera's Rotation While On Curve Constraint Path

08-26-2011, 10:58 AM
Hi All,

I am working on animating a rollercoaster ride from first person along a track we have modeled. I created a spline in modeler that follows the entire track and put it in Lightwave. In my camera's motion options, I used the curveconstraint modifier and locked the camera to that so it travels the path. I also added a null that travels the path a little ahead of the camera so I can try and better control the camera's rotation.

It works halfway decent, but I am having an issue when the coaster goes into loops and twists. For some reason, the camera snap-rotates exactly the opposite direction of any bank, twist, or loop. It basically reorients itself 180 degrees whenever it should be upside down.

I have tried manually rotating the bank and pitch in these instances with keyframes (using the heading and pitch controllers set to "keyframe") but when I make a change in the rotation the camera jumps off the path and I have to manually reset the position to 0,0,0 to get it back on. Then the rotation is messed up again.

I have tried unlocking the null from the path and using it as the target for the camera, while the camera continues on the path. For some reason, the camera wants to look in the opposite direction that the null is in.

I have tried playing around with the controllers and limits of both the camera and null, to no avail. Either I don't know how to use it correctly, or something about the path constraint is preventing the camera's pitch and bank limits from being effective.

Any help, tutorials, tips, or general ideas would be greatly welcome. I really don't want to have to manually animate the camera the whole way around the track; what I have looks really nice for the hills and straightaways, its just the rotation that's killing me!

08-26-2011, 01:31 PM
Use IK and/or pole item (pole vector). Targeting is much too simple and naive.

PS. if you need more help I suggest you post a scene with the roller-coaster motion path (or part of it) so everyone can test their ideas immediately and on something we know for sure is similar or equal to your situation.

08-26-2011, 01:45 PM
Yup... more or less what even suggested.

Id parent the camera to a null first, and constrain/target that null to the path, then use other nulls to provide for independent targeting and poling of the camera itself.

08-26-2011, 04:01 PM
Hey guys - thanks for the suggestion! I have parented the camera to the null, but I am not quote sure how to use Pole Item... I am assuming that would be the "Align to Pole" heading controller in the Controllers and Limits tab? I'm not quite sure what to do from there. I tried adding my target null as a pole item, and it seemed to just make the camera "cocked" from the start, rotated about 50 degrees on the B axis. I also tried it as target, and with both.

I have attached my scene minus the actual coaster so you can maybe take a look and let me know what to do next. When the camera reaches the first loop around frame 290, it needs to bank left instead of right. If you can show me how to get proper reliable roll control on the camera I would be extremely grateful!

08-29-2011, 10:44 AM
Hey guys, anyone gotten a chance to take a look at this? For now I have just been manually animating the camera (no track) but its not optimal. If anyone has any suggestions, I'm still all ears! :D

04-21-2012, 12:55 AM
Use IK and/or pole item (pole vector). Targeting is much too simple and naive.
IK? ::ponders:: You mean like a virtual camera crane?