# No Linear in motion, WHY!!!

I really dont get why, in the 1d editor, for rotation and scale, you can choose a keyframe and make it linear, whereas in the 1d editor for motion, you cant!!! See, imagine i have 3 points (in the 1d editor for motion)…first 1 at frame 1 (value 0) another at frame 24 (value 0) and a 3rd at frame 48 (value -5). Making the 3rd point have a value of -5, means that the line between points 1 and 2, changes, rather than staying linear!!! Plus there are no handles to even make the line linear if you choose, so basically, they layer starts at 0, slowly moves up and then back down (so that its still 0 at frame 24)!! How can i change this? Does anyone have any ideas? I really cant think what to do, any help greatly appriciated! Thanks,

Chris.

Hello Chris
The shape of the function curves in the motion path editor is controlled by the Velocity curve. This has the usual reshape controls.
It’s a pretty awkward and clunky way of controlling curves especially if you’re used to 3D software but there must be some reason for it.
Cheers
Ken

btw,
there is practically no linear motion in the nature. you have almost always an ease-in and ease-out…
rob

Thanks Ken, i am used to using 3D But anyway ive tried what you said, and made the velocity curve linear but it still doesnt help. Gester, i know this BUT, its not about that, ill show you what i mean: http://www.killamarshphotoclub.co.uk/1d%20editor.jpg
Hope its clear what i mean from this…just to clarify i havent sorted this yet so i need more help please

chris,
ok, i know what you mean. i’ve tried to play a bit with the motion paths and i did the following:
1. i pushed the vertical ruler (bottom right) to the top to have the curves more flat.
2. i added a new keyframe between 1 and 2 to make the horizontal line out of the curve (it’s now almost horizontal).
3. i re-positioned the keyframe 3 to have the remaining curves as i originally wanted them.

i hope it helps a bit.
rob

update:
but i don’t know if it’s enough. it seems to only scale, actually.
but there are no more controls, i fear.

Hi Rob, i didnt quite get what you meant, you said about the ruler in the bottom right but i cant see one, maybe u have tb3 and i have 2.5. Having said that, you gave me the idea to put a new keyframe between 1 and 2, but only 1 frame before 2…so 2 is at 658, so i put a new one at 657. This meant 99% of the line was horizontal with only a slight jump between points 1.5 (the new one) and 2. However i wanted to check how much it moved between them, so i zoomed right in, and noticed the layer was moving left to right too, over the course of the animation. I looked in the motion editor for east to west and sure enough it started at value 0 and finished at -1, so i changed all points to 0, created a flat line btwn start and end, went back to the North/South editor, looked at the rising area between (original) points 1 and 2, and it was linear, exactly how i wanted it! I dont think i change the East/West settings at all, so maybe tb did it automatically :S anyway!! Thanks for your help both you of, wouldnt have worked it out without that last post rob, cheers

Chris.

Hi there,

Great topic guys !

What I think happened is that you probably somehow changed the Tension, Continuity or Bias settings. You might have unlock a key frame (which makes a motion point) in the function editor window (the 1D editor) or you manually slide the bar in the properties window.

These settings change the way a motion path look between two motion points. This can be used when you want to create particular shape for a motion path like a circle (image a dog running around a tree … you would want it to running in circle).

If you would like to create a circle with 4 key frames or motion points (12h, 3h, 6h, 9h) you would end up with a rounded square motion path because by default the curve between two point is half linear half round (zero). If you want to create a round curve you would set the continuity to 1. If you want a perfect straight line you would have to set it to -1.

To bring these settings just select a key frame or motion point in the camera view and go to the properties window, click on the “Peg” tab.

Note that these settings cannot be applied to the first and last key frame because the curve is not on both side of the key frame. Add a motion point (shift click) to start and finish a round path.

BTW, If you are doing cut out animation and are used to 3D software, go to the properties window in the scene planning tab, click on “Create linear spline”. All curves will always be linear like in other digital animation software. You set the velocity by adding or removing frames between two key frames.

Hope this helps.

Cheers,

Hi Mathieu, thanks for the info, i dont think i did change the tension etc, but this leads me onto something else…in fact 2 things Hope you dont mind me going on here. Firstly, i dont think i changed the tension setting because, if you create a keyframe in the 1D editor, it doesnt show them on the side and top views, so i cant have even accidentaly changed the tension on them can i? (how come they dont show?) To change the tension i have to choose the keyframe in top/side view first and since i cant do that i cant change the settings…i guess
Secondly, i dont like the fact that the tension changes both side and top properties. Im not being too clear what i mean here, so ill show you: http://www.killamarshphotoclub.co.uk/views.jpg
Is there any way to change this, or is it just something you have to put up with? THanks for your help,

Chris.

Hi talk2cotton,

You are right, selecting a keyframe in the 1D editor is not going to show up these values. You would have to select a keyframe in one of the 3 main windows (camera,side,top).