I have a problem to make an effect in AE. I have a comp representing an animated graph (I use the motion tracking) in 3D. I also have a footage of a river. I want my graph to reflect on the river. Do you know if it's possible and if so, how could I create this effect?
Duplicate your graph layer. Make it 3D. Adjust its position, orientation and scale so as to make it appear as a mirror image of the original in the plane of the water. Reduce its opacity to make it appear as a reflection. Apply Effect > Distort > Displacement Map and select the water footage as the displacement map layer. Adjust the displacement settings to your satisfaction.