follow/track a shape/path

Software Natron
1

Hi everyone,
I am looking for a circle translating in a non linear way, following a curve.
How can I do a spatial non linear translation?
I tried a Roto with a Bezier path/curve and connect it as a source to a tracker node, but I can not get a non linear timed path.
Any idea?
Thanks for your time.

2

Hello, as far as I know, in Natron it is not possible to transform the path into keyframes.
However, you can do frame by frame tracking, use keyframes or use some expressions to do basic translations.
For example, in Transform node setting x to:
sin(pi*frame/20)*100
and setting y to:
cos(pi*frame/20)*100
will translate the object in a circle path with radius 100 every 20 seconds.

Hope this helps…

3

Thanks okhostok for the reply.
I take note that what I wanted to do at first was not possible. And your suggestion is interesting, I will give a try to that, however, I don’t know the x and y equations to get mime the path I wanted…
Anyway, thanks for your help and time.

4

By the way, I wanted to show some RotoPaint. I will show how to draw a star using paths:

  1. On Node editor, press P. It will add “RotoPaint Node”

  2. Select Pencil Tool: image

  3. Draw Path: image

  4. Create Transform Node and create a timing that you like on scale property. (optional, but it gives you more control about the timing)

  5. Connect visible portion’s left property (it goes from ending to beginnning, right property to go from beginning to ending) from stroke tab to transform node
    The animation will appear!


    Sample file:
    93.ntp (114.7 KB)