camera is following a path

[Filip Vandueren]

the easiest way would be to position the camera like you want it relative to the ‘path’-layer,
then just parent the camera to the other layer.
I’m not sure why you’d need an expression for this, or do you need seperate ‘unparented’ rotation ?

If so try it with a 3D Null: give the Null the expression, and parent your camera to the Null, so you can still rotate and position it.
Also if you want to lag a bit behind the other layer’s motion, look into the valueAtTime() method.

for example:

layer(“Path Layer”).position.valueAtTime(time-0.5);

[Sam Moulton]

there is a tutorial about using expressions with a camera here. don’t have time to look it up but its called something like camera expressions. it should give you what you need

[Thea Birgit]

thanks Filip
I have a solid with stroke 3D from trapcode. there is a mask which stroke is follpwing and the camera should follow this stroke. any suggestions ?

[Filip Vandueren]

You should check out these two episodes of Aharon’s Podcast:

Scaling a Motion Path
https://media.libsyn.com/media/aftereffectscow/CC_Scale_Path_POD_NewOpen.m4v

Importing a Motion Path
https://media.libsyn.com/media/aftereffectscow/CC_Import_Path_POD_Final_1.m4v

Now you know how to convert a maskshape to movement, just apply it to a Null, then make it 3D.
If you’ve rotated, moved, scaled the stroke with trapcode, parent your moving null to another 3d null and rotate or scale that to match.
Of course, if your stroke is also warped or bent by 3dstroke, the actual drawn stroke won’t correspond to the shape of the mask.

Be sure to enable the comp camera in 3dstroke.

you should see the null animate along the same lines as the stroke is drawn. As Aharon discusses, you’ll have to line up the timing by hand.

If all of that is OK, position your camera at the start, above and behind the moving null, then parent the camera to it. You might want to turn on auto-orient along path for the motion of the null so it banks around while following the motion path.

Depending on the complexity of the mask, you’re sometimes better off simplifying the motion path a bit, or making it’s corners smoother.

[Thea Birgit]

I will try
thanks a lot
with greetings from munich