you could either do that or simply create a path with the mask tool, select the mask shape, and copy paste it to your lights point of interest. Assuming that your artwork is oriented along x and y this would be the easiest setup. If you go for keyframing your path, make sure to select all keyframes between the first and the last one, right click and select "rove across time" to give your animation an equal temporal distribution or in other word the speed is always the same.
- AE does not have "visible" lights, ergo you will have to use some effect
- effects per se do not automaticalyl accumulate results ofer time so moving on to the next item
- you will have to use additional effects or
- think of an entirely different approach like revealing the shapes with wipes or re-creating them with stroke effects
Whichever way, it's not gonna be just a handful of keyframes based on a cissoid motion path, even more so since overlaps with semi-transparencies/ blending modes are involved. Your best bet would be to create real areas, then use some stroke effect as a tracking matte. Additional pre-composing to create the mutual obscurations/ cutout will also be necessary.
Given the little details bdaul is ging about his desired effect I guess you are interpretating to much into it, just yet
and your artwork is just flat (2d) but you want it to receive light and shading?
I am not sure what you want to do. Do you want to have a lighting effect like a highlight move around this shape as if it were a 3D object so that it goes behind certain elements? Do you simply want to set this layer as a 3D object and illuminate it withn a 3D spotlight in AE?
Both involve using the pen tool to draw the path on the object. The first option involves multiple layers, the second simply means you need to attach the point of interest of the spotlight to the path. You can easily do this by first setting up your spot light so that it is pointing gennerally in the direction you want. Then draw the mask path on the layer, open up the mask property by pressing the M key and set a single keyframe for the mask by clicking on the stop watch. Now Copy that keyframe.
The second step is to select the point of interest for your spot light and set a keyframe there. Now select the keyframe for the point of interest and Paste.
Moving a highlight around this object like is more complicated. If you want to end up with something like this then let us know and we'll try and walk you through the steps.