Okay first up are some new, more finalized renders with the ‘outside’ parts finished and included.  It was tricky to get so much into a scene that my humble computers would render in a realistic timeline, the solution ended up being to have everything on the other side of the window to be projection mapped renders onto simple geometry.  I’ll go into the whole process after the jump, but the result is something I’m really happy with.  Better than just putting flat renders out the window there’s real depth, so camera moves are convincing and depth of field is accurate.

Projection Mapping the Outdoor Scene:

Here we have the set for the outside of the school.  The characters don’t spend too much time out there but it was something I really wanted to have proper detail with because it would be visible in the background for all of the first scene (which is almost 40 shots).  So I got to work turning my preliminary model into something a bit more refined.

Unfortunately for each of those 40 shots the calculations for what’s out the window would be unacceptably long, and outdoor lighting is very much independent from indoor.  The light from outside does do a lot for an interior, but the light form interior doesn’t usually cut it compared to the light levels during the day.  So I committed the lighting outdoors and made it ignorant to the active lighting setup used for inside the classroom.  Projection mapping is perfect for what I needed, all of the views would originate from a location along the windows so the issues with projections tearing wouldn’t ever come up.

Now my experience with projection mapping has been using photographs and recreating simple geometry to map it onto. this was exactly the same, but I didn’t have to do any stitching because the cameras I used to render the scene were the cameras I used to project back onto an analogue.  I went for projections instead of baking for two reasons; first the grass would have been a nightmare and I likely would have ended up projecting at least that, second because I had a lot of practical detail instead of just texturing (like the brickwork which was all real geometry).

So I set up a bunch of overlapping cameras, a lot like how I shoot HDRI’s without a fisheye lens; piece by piece.  Then I rendered out 2K plates for each and did a bit of detailing in photoshop so everything would play nice.  Then I replaced the forest with a plane and the school with some cubes and projected my renders back onto the scene. Voila!  As long as you’re looking from the same perspective as the renders were taken from everything looks great, and best of all it takes no time to render.

The only place projection didn’t work was on the trees in the middle of the field, for that I baked the textrues and lighting on them.  They had too much occlusion to work with projection mapping, it would have taken lots of projections to get there, this was much easier.

Of course for the outdoor scenes I wont be using the baked trees.  The forest scene needs to be light accurately so each tree is believably lit, and looks unique from the others.   Here is a prototype render for the path through the forest, I think the final layout will have lots more trees.