Just a few days ago I enrolled in the MP4FM (Matte Painting for Film) Camera Projection Boot Camp by Garrett Fry. I'm excited about getting more in depth info on creating complex camera projections for my matte paintings. I've been using camera projections in Maya for a while, and more recently started doing them in Nuke. I've learned some really cool stuff so far, like how to make a nested projection, and setting up multiple projection cameras for a complex shot. I already have some ideas for future matte paintings to try out these techniques!
If you're interested in learning more or signing up for the course, check out the video below or go to: