Cineversity

Hi:

I think I could make my life easier animating the cameras for my scenes with the assistance of the Time Track.  I’ve used it now and then, but not consistently, and usually not for camera moves.  A lot of my stuff involves flying a camera around a piece of hardware, combining fast moves with slow drifts.

My understanding is that I should be able to plot some sort of object movement using as many keyframes and beziers as I need to create the path I want, then apply a Time Track to those position tracks to control the temporal movement.

The problem I’m having is that the Time Track isn’t really forcing a constant velocity to an object moving along a bunch of bezier curves as I would expect.

In the attached scene I have a cube moving along a sort of S-Curve.  I’ve created the shape of the curve with four keyframes shaped with bezier handles.  The cube is moving along the path I want in space.

I then create and apply a Time Track to the X,Y,Z portions of the cube.  With a straight, linear line on the Time Track going from 0 to 100 I would expect the cube to move a constant, linear rate along my S-curve, but it’s not.  It slows down at the end of the first curve, moves slower along the short, straight section, then speeds up to the end.  I’m guessing this has something to do with the spacing of the ticks in the original spatial curves.  The cube moves slower where the ticks are closer together, faster where they’re spread apart.

It seems to me the Time Track should be overriding those ticks, essentially creating new, evenly-spaced ticks if the Time Track is set to linear time.  But it’s not.  Maybe I’m missing a keyframe setting somewhere.

The only way I can sort of make this work is to drag around the keyframes of the original curve animation in the Timeline until I’ve evened out the ticks, but that sort of defeats the purpose of the Time Track.  A Rove Across Time feature for those keyframes, as in After Effects, would be handy in this situation.

Yes, I could set the keyframes on the cube to Constant Velocity to get this effect, but there are going to be times where I want my camera to accelerate to a position, decelerate, move at a constant velocity, accelerate again to the next position, move linearly again, etc.  I was hoping I could plot out the path I wanted and use the Time Track to control that timing.

I don’t want to use a spline for my camera to move along, either.  I find that way to difficult to tweak.  Maybe a Time Track applied to Align to Spline would make that easier; I don’t know.

Thanks.

Shawn Marshall
Marshall Arts Motion Graphics

Hi Shawn,

Thanks for uploading the file to my Dropbox.

What you are looking for is the Time Line> Function> Set Constant Velocity. The Time Track is not at all the tool to get this.

https://help.maxon.net/us/#32176

The Time Track, if left as you got it and if applied as is, will not alter any movement, as long as the start (0%) and the end (100%) matched the first and last keyframe. In your scene, it is not set to be on end.

It will not linearize nor streamline any animation. It is a graph that plots the keyframes from 0% to 100%. IF the Time Track is altered, then anything will change that falls to a different “curve” than 0% to 100%.

What you expect is not give with the Time Track.
Since it has the most non-intuitive management options, I would avoid it. Example, you can create one Time Track and apply it to many keyframe tracks. Perhaps have three different ones. All three distributed to different groups of 100 objects. Where one Time Track is applied or the other, is not given as an overview, you have to explore it on a case by case base.

I fear, I can’t change it, so it follows your idea about. It will not force any evenly distributed velocity. It would be a lot of work to get this done and then the Time Track would look like a wiggly F-Curve in the F-Curve manager.

Another thing that is impossible to do with one Time Track, distributed to X, Y, and Z, to have a different speed set up with it for z, while leaving X and Y untouched. But that is pretty much what most camera movements need, to change the position on each axis independently. So if the X moves faster on the start, but the Z has a higher velocity in the middle, and the Y speeds up on end, one Time Track will not change that.

Speaking of Splines: Any spline can be turned into a Motion path, and any motion path can be turned into a Spline. Function>Spline to positions Track. Position Track To Spline. The Spline can be converted in a MoSpline while setting the points to even of whatever is needed. But I guess my initial suggestions Function> Set Constant Velocity should work.

Otherwise, try the Morph Camera, it has a beautiful slider [Blend], and you define all the Key Positions needed with it. Explore of course how things will change if a camera is added or deleted from the Camera Morph Tag list.

All the best

Hi:

Thanks for looking at this; sorry for the delayed reply.

It’s too bad C4D doesn’t really have tools that let you divorce the positional curves from the temporal ones, despite what some online tutorials would lead one to believe.

As I wrote initially, I wasn’t really looking for completely linear timing; I just thought that would be the most straightforward test of the Time Track.

I ended up creating a rig of parented nulls to get me the smooth moves, offsets and orbits I needed for my shot.  I will use camera morphs to blend between camera moves that would be impossible to pull of with one camera, but I didn’t want to wrangle 4 or so cameras for one basic move in this scene.

Best.

Shawn

Hi Shawn,

Thanks for the reply. You found a way, good. Please let me address the other points.

No idea how you get to that conclusion, so please let me explore this. The TimeTrack is not equalizing the velocity and then map it to a 0-100%.  That doesn’t mean you can’t create it. You are not clear about if you like or not to linearize it, it is either constant or not constant, there is no temporal something in-between. Perhaps I miss something here. Let me know. TimeTrak is a curve based option to set keyframes of one or many tracks in a way like with an range-mapper in time, nothing else. It uses the keys, either where they are (Relative Mapping), or as it is set automatically.

Please let me try again to go though a step by step, as it might confuse otherwise people reading along:

If you need to get a constant Velocity: Create your animation, then use Function> Set Constant Velocity. If not leave it as is.

You can apply the time track: To one or many tracks. It takes the animation from the first to the last key-frame, and every setting on the curve will reflect that position, accordingly to 0-100%. To make that point more clear, if the ‘curve’ starts with 50% and keeps it to 50% to the end, no animation will be given at all.

You asked about Time Track. If you need a one single control Curve interface (Spline-Interface), then turn the animation into an Animation Clip. Also here, you can apply constant velocity before you convert it to an animation clip.

Which are the tutorials here on Cineversity that gave you a wrong impression?

I hope this little one minute clip helps:
https://www.amazon.com/clouddrive/share/gBKzgoGOmQswKOjWpyymgms6xiKnDFP1jjVufh9tUog

All the best