Keyframing issue

I'm trying to do linear zoom in to left top corner.

First I create keyframe position 0,0 and 100%. Then next keyframe position 33.6, 18.9 (left top corner) and 138%.
This will create movement over the left and top corner and then back to desired position. In other words it will go over so in the middle of the movement you can see the black background for a moment.

I'm trying to do pc guides that will smoothly zoom in from to different parts of the screen to better show current program windows. This drives me nuts. Please, can anybody help?

Samplevideo

There's two keyframes:




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Tomi

Yes, odd, it looks like there's three keyframes going on almost. I'd remove all the keyframes, and only keyframe the three parameters you need, not all of them. Not sure you have rotation and Z position stuff going on there. Keyframe your position X and Y only, then scale. Then in the new position keyframe only those three parameters again. See if not including all the other non-essential parameters helps.

Thanks for reply, BenB.

I did remove extra parameters. Now both like this:


Still same issue. There's a weird S-curve in motion:

Samplevideo


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Tomi

The animation editor seems to have a long way to go, I tried, and failed, to work out a way round this. It looks like each keyframe defaults to a non linear state creating a strange accelerating/decelerating motion path.

The "Compositing: Opacity" bit in your screen shot has a little disclosure triangle to the right, it's by selecting this you open up the curve to make adjustments to the motion path, but hardly any of the parameters have the option available, I was thinking before that it seems like less than in 10.7.2, but I may be wrong.

Hopefully I am wrong and someone has an answer, but it looks like a wait for another FCP update to add the functionality.

OK, tested, I know what's happening. It's all working perfectly, but this is a common compositing mistaken assumption. Thus I will give a brief tutorial on it here. I'm sure others will benefit from this, also. Remember we are coordinating two separate functions, two "separate" functions that do not talk to each other at all.

1- The image is moving from center to lower right. This normally would leave black on the top and left.

2- The image enlarges over time.

We are "assuming" these two parameters will magically lined up. But since there's no magic, they do exactly what you tell them. AND remember we are working with a rectangle who's top and left sides are NOT the same length, so movement along each is not equal. If this were a perfectly square frame size what you're trying would work right off the bat, since the top and left sides would be equal lengths, and movement along each would be equal.

The image is enlarging over time, but not fast enough to keep up with the move to the lower right, due to the rectangular shape. The top left corner travels in one direction faster to the right, than it does down, as the image has to move more distance in that direction, than it does down, because it's a rectangle. So we have to tweak things. That can be done in one of two ways.


METHOD 1:

1- Set beginning and ending keyframes for both Position X / Y, and Scale.

2- At about every quarter of the way between the start and ends keyframe locations in the timeline (zoom in enough to work with the necessary detail), you'll have to tweak and keyframe the position's X and Y parameters so that the top left corner stays in place.


METHOD 2:

If you want that corner pinned down the whole time and smoother motion with less work, then change the Anchor point. Then you only have to keyframe the Scale parameter, NOT the Position. Anchor Point is where the image is "pinned down", which is by default it's center, X=0, Y=0. Example, rotate an image, it rotates around it's center. Change the Anchor Point half way to the top right corner, and it rotates around that point in the frame.

Here's the odd part. Someone at Apple decided that the X edge of the frame is 88.9, and the Y edge of the frame is 50. Possitive or negative depending on which direction from 0 dead center you're moving. So...

1- Set your Anchor Point for -88.9 x 50.

2- Move the whole image back into place in the frame.

3- Keyframe only the Scale parameter as needed.

Absolutely right. The interpolation seems to default to Bezier so there is a kind os S curve applied and no way to switch it back to Linear.

However, I have knocked up a (very) crude Motion filter and it seems to work as the parameters default to Linear interpolation. Install this in your Movies>Motion Templates>Effects folder and then apply the effect to your clip. New x, y and scale parameters appear in the Inspector which you can keyframe. Let's hope Apple sort this out soon but in the meantime this should stop the 'Bezier wobble' for now.

Ian.

I also noticed that the position and anchor point parameters default to bezier, but the scale looks like it defaults to linear. Which if right enough, would explain the strange motion path.

it would also explain why changing, but not animating the anchor point works.

Actually - just tried the filter again and it defaulted to Bezier! I think I've had this before - and, of course, Ben could be right!

Were all right on this one. It's changing the balance between the anchor point and position parameters that removes the need for the bezier motion path.

It's a good workaround until the features get added.

I enhanced my mini-tutorial up there. It's all about the rectangular shape. You'll see the same thing happen in Motion, too, with a 16:9 image. Nothing to do with bezier paths, it's the unequal sides, creating unequal speeds between horizontal and vertical movement. There's no "magical feature" that would change the geometric limitations of the movements.

Guys - explain this then - if I work backwards by setting the scale of the end of the move as the first thing I keyframe and then the x and y to frame the corner in the corner (top left) then I go back to the start frame and set the x and y to 0 and the scale to 100 the move works without 'shooting off'. If I set the x and y first I see black during the move.

This also works for my crude filter - which makes it useless as well as crude!

My money is on the overall interpolation being set by the default interpolation of the first parameter that you keframe. Ben, I know you don't think this is a Bezier issue but...

Ian.

I've not looked at your "explain this" yet Ian, I will just now. But first it is definitely a bezier issue. The reason it works the same in Motion is that it also defaults to bezier for position. It's less relevant but it defaults to linear for scale.

Ben if you open the keyframe editor in Motion change everything to linear, it works like it would in FCPX if it defaulted everything to linear.

I could not fix this. I tried to anchor, no luck.
Finally I did notice that setting (in this case) exactly 45 frames transition will work ok. A few more frames more or less will cause same issue.
This is acceptable workaround for me. Result is not exactly what I was looking for, but I can live with it.

In this sample video you can see it works ok, when motion was slowed to 45 frames. Second move is only 20 frames, but it works ok.
Samplemovie

Thanks, everybody.

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Tomi

I did it, works perfectly. What's the frame size of your timeline?

We don't have control over bezier vs other path types in FCP X, so that's not a solution. I provided one that I tested and works. If you set the anchor point to the correct place, you only have to change the Scale.

1920x1080, but that should't matter.

When working in FCP X, yes it does. A square image will do this effect different from a rectangle. I tested a solution, there you have it.

By the way, it will also work properly if the scale and position paths are both are set to "Ease Both", as by default they are matching acceleration/decelerations, it's if the bezier curves don't match or if one is linear and the other not that the motion path is wrong.

Ben, the reason your work around works is that the bezier path has been removed from the position, by adjusting the un-animated anchor point leaving the only path as linear.

Ian, in FCPX I can only get only get position parameters to animate with a bezier curve and scale as linear, regardless what order I apply them. I'm wondering perhaps that time you made the keyframes less than 45 frames apart as Tomi did. I noticed doing this the curve is very little at either end an mostly linear across the animation, minimising the problem.

Tomi, when you used the anchor point as suggested by Ben did you keyframe it rather than the position? If you don't keyframe it, just move it to the centre of where you want to zoom in on, then adjust your position to bring the frame back into line you only need to animate the scale parameter. This will give you the option to decide how long you want the animation to last back.

Ben, that's because of the maths related to a square and adjusting from the centre to the exact corner.

When you apply the position keyframes to the square (from centre to corner) the bezier handles align with the curve, giving a linear interpolation motion path, but with handles. Go in to your square motion project and adjust the handles slightly, or end the path so as it isn't in the corner, you'll get the same bezier motion path that doesn't match the linear path results.

I just thought of a better way to explain it.

There are 2 ways for Apple to fix this problem.

A. Ask the world to change to using square televisions.

B. Change the interpolation of scale and position to match by default.

The default is Linear in FCP X, it can be changed to Smooth if you right-click the point in the Viewer, it's hard to click just the right sweet spot, but the default is linear. Unfortunately there's no control over Ease. But, the solution I gave works both in Motion and FCP X.