This projection technique relies on the concept of getting a complex animated scenario with the minimum time of rendering possible, so in order to get that result, we need to optimize the scene. This means we are going to replace all of our high model objects with very low meshes – in most cases a simple plane mesh will do just fine. Remember that the high level models were only made so that we could get a good and solid base 3D render to paint over it; they weren't intended to be used at the moment of projection. If you use the high models you'll end up having the following problems: weird artifacts, strange behavior of the projected texture on your mesh and crazy rendering time that you don't want!
So as you can see in this scene we replaced our original high model scenario with a proxy version of it, and for all the elements such as tables, musical instruments, shelves, etc we simply used plane meshes for each object.
Replacing high level objects with planes (Fig.12 & Fig.13).
Base mesh for the interior (Fig.14 & Fig.15).
Here are some useful tips about the setup that worked best for us:
You may find some differences when you compare the original paint you made with the projected render, like over-exposure, brightness and contrast differences, etc. This was a problem we suffered at the beginning. We erased all the lights in the scene but the problem was still there and it was really annoying. We found out that by changing the settings of levels and ambient from the global lighting it worked just fine, so we changed the level to 0 and Ambient to pure white (Fig.16).
When you export your paint images for projection, remember to save the alpha channel data. You can use extensions like TIFF or TGA for that.
Keep it simple when moving the camera around. This technique gives you the possibility of using a single frame paint and moving a camera around, but it doesn't make miracles!
Render & Composition
The render stage in this scene was really easy and enjoyable! The only thing we rendered traditionally was the character; we used the high model scenario to place our character and to add the lights in order to use it to cast the shadows properly. Then the rest of the elements were all projected and rendered separately.
We took all the renders to the composition software and we just layered them following the correct order of relation towards the camera. Then we took advantage of having each element separated so that we could adjust levels, brightness, contrast, color correction – anything that helped us to create a sense of depth in our composition (Fig.17 & Fig.18) (Mov.03).
We hope this Making Of overview helps you in some way and we just want to point out that this workflow is the one that worked for us, but that doesn't mean it's the best one.
Mcfly Studio, Animation Team