I have an empty parenting a camera and the empty is following a bezier curve thru a constraint. I have the camera 'Track'ed to' a moon, but as the Empty/camera travels along the bezier curve I want to switch 'track to' from the moon to the earth at some definable point. How can I do this? Also the Empty/Camera contines to run beyond the end of the bezier curve. How do I get the Empty/Camera to stop at a definable point and just focus on the earth
As TheLabCat wrotes you can just add a second track to constraint to the earth.
Then you can animate the "influence" values of both constraints as you need it. 0 means no influence 1 means "full" influence. So you should animate the value for your moon constraint from 1 to 0 and at the same time the value from the earth constraint from 0 to 1.
For the animation, use the object constraint "follow path", choose your path and insert keyframes in offset for value 0 and -100.
video tutorial here: https://youtu.be/qFv25Up6LzE
you can cross fade an animation in VSE.
Open VSE. Insert both movie strips or images sequences. Move them in that way that they do overlap. Select both. Then Shift-A -> Transition -> Cross. By moving the strips you can lengthen/shorten the crossfade-effect.
video tutorial for cross-fading: https://youtu.be/KgiXJvW5tvk
I see this is 2 years old but I'll throw an answer in just in case anyone comes cross it.
When you fade from 1 Track To to another you need them to both share the same frame where one has an influence of 1 and the other has an influence of 0. Move along the time line a few frames and then change the influence of the first to 0 and the second to 1. If you press the record button above the timeline before setting the influence, it will automatically add a keyframe for each of the times you changed the influence setting.
This will create a pan to movement across those frames. If you want the camera to immediately snap straight from object to another object with the Track To just make sure the influence change from 1 to 0 and 0 to 1 happens in the space of just two frames.