Dynamic Keyframes ?

Gary James wrote on 9/20/2009, 2:54 PM
I'm trying to find out if what I want to do is possible in Vegas. Basically I want to know if I can create a keyframe, change one of it's properties, then later move it along the timeline and have certain other properties be updated from the value that would exist on the timeline if the keyframe was not placed there.

For example, lets say I do the following:

I create a new project.

I add a 10 second test pattern video.

I change the event Composting Mode to 3D Source Alpha.

I open the 3D track motion window and add a keyframe at 5 seconds. And set the Z Rotation to -360.

I then add a keyframe at 2.5 seconds and set the Z Position to 600. I then set the 5 second keyframe to the same Z Position value of 600.

I play the video and watch the results. The test pattern makes one revolution in five seconds, and zooms away from the viewer and stops moving after 2.5 seconds. Now, this is where the question comes into play.

I decide that the test pattern should move away and stop zooming at 4 seconds, instead of 2.5. So I drag the keyframe from the 2.5 second position to the 4 second position. I check the video and see that I get what I want for the zoom away effect. But I've also changed the way the rotation behaves. Instead of making a smooth rotation from the 0 to 5 second time period as it did before, it now rotates slowly from 0 to 4 seconds, then speeds up from the 4 to 5 second timeline positions.

So, moving the keyframe to achieve one effect, had an undesirable side effect by moving all of the parameters that were set at the 2.5 second time period, to the 4 second time period.

What I would have liked to do was somehow tell the track motion controls that I wanted the Z Rotation property to be dynamic. By that I mean I want to move everything except the Z Rotation value. And for that I want it to automatically update its value to the Z Rotation value that existed on the timeline at the 4 second position before I moved the keyframe.

Is this even possible in Vegas? If not, is there a work-around for this unwanted side-effect?

Comments

farss wrote on 9/21/2009, 1:56 AM
"Is this even possible in Vegas?"

I don't believe so because one keyframe stores all the parameters.
You can get someway to what you want by using parent and child controls e.g. use the track to control the rotation and the 3D parent to control the Z axis. However you still have to adjust everything by hand.
If you want dynamic links between parameters you need one of the dedicated compositing applications and a fair slab of time to learn them. So far I've found it generally quicker to just do it manually in Vegas. If you plan on doing a lot of this kind of work then invest the time to learn a new tool.

Bob.
TheHappyFriar wrote on 9/21/2009, 5:13 AM
in your case it would be easier to make a new keyframe & retype the values you want in manually. it's pretty easy (or if there's a lot of values, reset the few you don't want back to defaults).

but that's how keyframes work. Some apps have more keyframes per frames then others. IE Blender has a keyframe for XYZ movement & rotation instead of a single keyframe that keeps all these ideas.
Gary James wrote on 9/21/2009, 7:25 AM
"in your case it would be easier to make a new keyframe & retype the values you want in manually."

I suspected this was the case. This whole question came about while I was doing some 3D track motion tests with a parent window and several child windows.

I wanted to move the parent window in a smooth arc while doing a zoom in effect. While setting up the keyframes I found that the position of the keyframes on the timeline was vitally important to the smoothness of the arc. Depending on position in the timeline, the movement appeared either fluid, or moved in a pronounced point to point manner.

But while I was tweaking the timeline position to control the smoothness of the arc movement, it was messing up the smoothness of the zoom in effect. Adjusting all these parameters in 3D space, is becoming a much bigger task than I had anticipated.

It would be nice if Vegas had Bezier Curve control over track motion keyframes like you find in the Mask function edit controls in the Event Pan / Crop dialog. Simply position two keyframes, then use a Bezier tool to define an arc between them.
TheHappyFriar wrote on 9/21/2009, 9:11 AM
i've been asking for keyframe curves since vegas 4. :) Sony replied publicly to some questions this year & asked. They said it's on the drawing board but not in the next few years (that was ~start of '09). would be awesome imho. :)