Pointing at a paper only helps the person standing next to you. Drawing on the live view helps everyone looking at the Mac or the projector. VeeCam can annotate the camera picture, and it can switch to a board when you want to write without the paper behind the ink.
Annotate the live view
Open the live view from your USB document camera, visualizer, or UVC webcam. Use the text and drawing tools on that picture to circle a step, underline a word, or add a label. Freeze the frame first if your hand would otherwise move the page while you draw.
Switch to a whiteboard
The light or dark board is for an explanation you write yourself, the way you would turn from a textbook to a whiteboard. Use it when the answer is not printed on the page. You can go back to the camera when you need the original sheet again.
What this is not
VeeCam is not a screen recorder, and it is not a filter for the built-in FaceTime camera. Recording the camera, or the screen, is optional when you need a lesson file. The main job here is the live explanation. Scans and drawings stay on your Mac.
Install VeeCam on the Mac App Store.
Related: Show a paper live with a document camera · Compare pages side by side · VeeCam