I am wondering how to create an animated arrow, one that would show an incline of growth on a graph.
I know how to make an arrow, but I can't seem to figure out how to make the arrow "grow" along a path.
I Agree that Motion lets you do this much easier and with more options and effects. But in the regular final cut timeline, you can also do this two ways:
Version one, make your arrow in complete form and save it with an alpha channel (psd, png, tif, tga). Be suer your final cut is set to recognize alpha channels correctly. Lay that graphic on a track above your video track. Use the final cut motion tab tools, or the wireframe mode, to get it positioned and scaled the way you want it to look when fully revealed. Next, inside the motion tab, find the crop controls. Move one of the crop edges until it covers the arrow. set a keyframe, go to the end of the clip, "un-crop" the arrow, set a keyframe. Done. The arrow will now on playback appear to move across the screen like mercury in a thermometer. The downside of this version is the arrowhead itself only appears at the very end, unless you ...
Version two: build the entire arrow, but twice as long as it needs to be. Crop the arrow shorter, set a keyframe for the start and end positions, then go back and keyframe the cropping of the tail end. This gets you the arrowhead all the way thru the shot.
Apple Motion does this whole thing much better; you draw the path you want, then the size and thickness of the line, the shape and type of arrow head and line cap, and speed of travel, and curvature... all these are more easily set in Motion.
Stephen Smith's Moving with motion DVD walks you thru this, it's worth getting.