I have a Layer A precomped then I have an angle control slider in the my main comp. I have pick wicked the Y rotation on Layer A to the angle control slider. It works fine but as soon as I try to keyframe the rotation it doesn't work. I can set the first keyframe but then when I try to set the next one it doesn't change rotation. I dont know why.
I option click the y rotation of Layer A then drag the pickwick to the main comp. The expression on the y rotation says - comp("MainComp").layer("LayerA").effect("Angle Control")("Angle") I get no errors so why can't I keyframe?
If I make the slider in the same comp it works ok but not when I want to link to a different comp.
I also tried to link the rotation of the object to oration of a null like this comp("MainComp").layer("Layer A").transform.yRotation; But this doesn't work either. The null just moves and doesn't rotate the layer. How do I do this please?
Edit - I setup a couple of new comps with the same so that I could experiment with the linking the rotations and it works fine. So for some reason the comp I actually want to do this in won't work? Could this be some kind of bug?
You have not provided any details about your sub-comp and how you are using it. The pertinent assumption would be that you are using some combination of collapse transformations, parenting or something else that prevent this. Other than that this could be a cache issue, but you really have to be more specific.
There is no bug. If linked to a property the values will change when you change the slider and the values will keyframe. I think this has to be operator error. You could also be using an effect that does not respond to transformations. There are a few. Without a screenshot with all changed properties revealed for the layers that are giving you a problem we can't very well diagnose your problem. Select the layers that are giving you problems in the timeline, reveal all changed properties by pressing the u key twice, take a screenshot then send it to use by using the little camera icon at the top of the reply window.
BTW, if expressions are not revealed also press the E key twice....