Tutorial: DIY Projection Mapping with After Effects
Thanks for the interest regarding this test I posted on youtube. I actually read this tutorial first; it's a good overview of projection mapping concepts:
After this, I wanted to try a quick projection mapping on a small cube I had around, because it is such a simple geometry to try first. I also wanted to use software I already have: Sketchup, Photoshop and After Effects—this tutorial assumes you know how to use these. You will also need a video projector and a digital camera for this. HereÕs how it works:
1) Open Google Sketchup (Free): Build a 3D model of a cube and export it as a .kmz file (Google Earth format)
2) Open Photoshop CS5: Open the .kmz file and save as a .psd now.
3) Open After Effects CS5: Select File > Import choose your .psd file. On the dialog screen do Import as Composition and make sure the Live Photoshop 3D option is checked. At this point you have a 3D object in After Effects. If you donÕt see the object well it may be that you need to add lights to see it or set your preview channel to Alpha.
4) Make a new square animation composition—I set mine to 200 x 200 pixels. Feel free to animate whatever you want. I did a 6 second animation of a red square growing from the top-left corner and disappearing into the bottom-right one. Alternately you could just do a static colored layer for the sake of simplicity and worry about animating later.
5) Drop this animation you just made into the previous 3D composition as a new layer. Set this layer as 3D layer. Duplicate this layer two more times: your composition should now have 4 layers (3 animations and 1 cube).
6) Switch 3D view to Front and move, rotate or scale one of the animations onto this face, until it meets the edges cube—this process is similar to applying wallpaper to a wall. Repeat this step for the Right and Top sides of the cube and align those two other animations as well (see example screenshot below).
7) Now grab the physical cube in your room and place it somewhere convenient for projection mapping. I placed mine on the floor of my living room.
8) Setup your projector higher above the cube and make sure it points down to it and that it has an interesting perspective (full frontal projection mapping wonÕt be so impressive, you want to project on 3 surfaces of the cube). Turn the projector on and confirm that it covers the cube with light. Connect the projector to your computer, but donÕt send your video signal yet.
9) Place the camera in front of the projectorÕs lens, point it towards the cube and take a photo—you are taking the reference image of how the projector ŌseesĶ the cube (see example image below). DonÕt move the projector any more at this point.
10) Transfer this photo to your computer and import it into the After Effects composition with the cube and the three animations. Do not set this layer as 3D though—it should stay 2D.
11) Move the photo layer into the background—your 3D cube and animations should be on top of it. Now rotate and move the camera view of the 3D cube so that its perspective matches the one in the photo as closely as possible (this part is a bit tricky, but be patient—see example below).
12) Once you get these perspectives to match, youÕre ready to test the projection mapping! Send your computerÕs video signal to the projector and project the After Effects screen. You may need to adjust zooming on the projector and on the AE composition. Once you get the AE cube to match the real cube press preview to watch the animation play and your first projection mapping come to life.
This is the basic theory of how this works. There are many steps omitted but this is how I recall doing this.