Lego Fallingwater

The Lego Architecture series has intrigued me since it first appeared, and this past Christmas I received a set of my own.  I thought it'd be fun to document the build process brick-by-brick.  A YouTube search revealed that my idea was not original by any means (over 50 similar videos!) but I still thought it'd be fun.  I've been wanting to try some stop motion with my older Sony digital camera anyway, and this seemed like as good a subject as any.

I built a camera stand from Legos, lacking a small enough tripod for the height at which I planned to shoot.  The whole setup was simple, and admittedly crude, and I would make a few changes if I were to repeat this process.  For one, the camera stand needed to be slightly more rigid, as evidenced by the slight jitter between frames.  For another, although the Sony image quality looks good it requires two AA batteries to run and this film went through two sets of batteries.  In the future I'll be getting an HD webcam if I decide to produce another similar film.

The "Studio" Setup

Although the stop-motion build-up was fun, I really enjoyed adding the live waterfall to the scene.  I used Blender with the Blam add-on for static camera matching.  The whole matching process was very straightforward once I got the latest version of the add-on installed.  (NOTE: when upgrading an add-on from an older to a newer version it's necessary to remove the old version, install the new version, AND restart Blender.)

I don't think I got the Lego geometry, for channeling the fluid simulation, exactly right.  It looks pretty good in most spots.  The 3D view of the geometry is shown below.  I tried to constrain the flow as it left the Lego creek bed.  This worked for the first part of the simulation, but eventually it overflowed and ran out the sides.

3D geometry matching the Lego creek bed (roughly)

To overcome this "leakage" problem I ended up creating a mask and compositing the Fallingwater image over the top of the fluid simulation sections that I wanted to hide.  I know where the masking is happening, and it doesn't look particularly obvious to me.  Hopefully that's true for the casual viewer as well.

This was the node setup used to combine the two shots and mask the overflow.