Using a track point to animate position value (but not take the absolute value of the track point)

[josephc89632329]

Hi,
I wonder can anyone help:

I'm using the clone stamp tool to make a correction to a shot.

I then track the motion in the shot (since the camera is handheld). The best tracking point is over in the corner of the frame, and bears no realtion to the location of the clone stamp.

I now want to animate(transform) the position of the clone stamp so that it matches the movement of the tracker.

If I use the pick-whip to link the clone stamp's position to the 'feature center' of the tracker, then the clonestamp assumes the absolute value of the tracker (which has the effect moving my clone to a position I don't want it to be in). Instead I would like the position of the clone stamp to remain the same, but be offset in the same way as the tracking point is being offset from it's original starting point.

Does that make sense?!

So if my clone stamp has a position value of x20,y100, and my tracker has a value of x1020,y1100, I want to link them such that if my tracker value changes to x1030,y1100 on the next frame of video, my clone stamp position will be x30,y100.

Please help!

I'm pulling my hair out here!

Thanks a lot!

[Mylenium · Accepted solution]

Basic addition and subtraction:

mRef=thisComp.layer("XYZ").transform.position;

X=mRef[0]+1000;

Y=mRef[1]+340;

[X,Y]

You may want to read the online help on expression basics.

Mylenium

[josephc89632329]

Thanks so much for your response. 

Yes, I certainly had the feeling that what I was  trying to do must be pretty basic. 

Will try implement your solution later today when I'm back on my computer. 

Will also defiantly look up the expressions online help, as you suggested - to get the basics. Have the destinct feeling I'm slightly out of my depth at the moment! 

Thanks.