How do I fake a movie projector screen on a solid wall?

[AceLegacy]

Hello.

I have a short film teaser I want to film, and in one of the scenes, a girl speaks directly to the camera while images appear on wall right beside her, as if coming from a movie projector.
What techniques do I use to achieve this effect, being sort of a beginner in After Effects (who is willing to learn much more)?
I've tried looking for an answer for my specific question and I couldn't find it.
Thanks in advance,
J. Felipe.

[Dave Merchant]

You can use the 3D camera tracking tools to "select" the plane of the wall, and position an object upon it. For a projection you need to set the layer blend mode for the projected image so it's not just a solid rectangle - the physically correct choice would be "Add", but that only works properly in linear color, so most people live with "Screen" then dial back the opacity until it looks right. You should also blur the image a bit since projectors are never pin-sharp, and maybe add a subtle glow. If you want the light from the projected image to bounce back onto other things in the scene then it gets very complicated very quickly.

For an into on how to track planar surfaces, see https://www.youtube.com/watch?v=0ToPGhr_muI

[AceLegacy]

Thank you, this helps a lot too.

[Rick Gerard · Accepted solution]

If the camera is moving then you have to do some kind of tracking. Corner Pin tracking using AE's built-in Corner Pin tracker, Corner Pin tracker using the included Mocha AE plug-in or Camera Tracking. Camera tracking is only required if there are huge parallax changes in the footage and the camera is actually moving. The best tracking option depends entirely on the shot. I would have to actually see the shot to point you to the most efficient workflow.

If the camera is fixed, locked off, then all you need to do is put the projected footage on a separate layer and then add the Corner Pin effect or make the layer 3D and adjust the position, scale and rotation of the image to match the wall.

If the actor moves in front of the virtual screen you will have to create some kind of a mask to either make a hole in the virtual screen or remove the background from the part of the actor that passes in front of the virtual screen.

As for color correction and final compositing, there are a bunch of options. The best tools also depend on the shot. You will have to consider color grading, edge control, blend modes, and effects. You may even want to add a subtle layer that simulates the light from the projector interacting with the atmosphere. Again, this all depends on the original shot and also the footage used as the virtual screen.

If you can show us the shot or shots you want to use then we can make specific recommendations. If you want to do some studying check the User Guide first or start with the tutorials on the After Effects product page which can also be found in the Overview section of this forum.

[AceLegacy]

Thank you so much! The shots will be filmed on Friday. I'll return then to provide better information, but this already helps A LOT. Thanks again.

[JakobSj�bom]

You did *not"* return.