BUILDING WITH BRICKS
FOR THE LEGO MOVIE, ANIMAL LOGIC LOOKED TO CREATE EVERY SINGLE DIGITAL LEGO BRICK IN THREE PARALLEL WAYS, AS HEAD OF PRODUCTION TECHNOLOGY AIDAN SARSFIELD EXPLAINS
1. LEGO DIGITAL DESIGNER
A massive part of the directors’ brief was to ‘stay true to the medium’, so from a very early stage we knew that we weren’t really going to be able to take any shortcuts. Because of that we committed to individually creating every single digital LEGO brick. One track involved developing models and designs using LEGO Digital Designer (LDD). Despite being a relatively simple app, LDD was an obvious choice for building our designs as it came with a complete brick library and reasonably advanced LEGO building capabilities. With each LDD model, we could generate a list of brick IDS and set to work on creating the required bricks, starting with the most commonly used.
2. DEVELOPING A BRICK FORMAT FOR DIGITAL BRICKS
LEGO Denmark had been kind enough to share their digital brick library with us, but the formats they used ranged from high-density CAD models to low-poly game models. None of those formats fitted our very specific needs. We were going to be path tracing, using subdivs, and we knew we were going to have to be very clever with our geometry optimisation. Things like the studs, with the stamped LEGO logos, needed to be seen in high detail when close up and would need to be culled when inside complex models. Similarly, the interior of each brick, with all the internal detail and even IDS would need to be visible in some circumstances.
3. SHELL BAKING
For each model built in LDD, we could use the brick positions, IDS, and material choices to ‘bake’ a geometric shell of the model. This essentially involved using our new digital bricks and merging them into a highly optimised shell for use in the pipeline. Importantly though, this shell maintained its reference to the original IDS and brick positions, so at any point in the pipeline we could restore the asset to its fully detailed, high-resolution, brick-based original. This provided huge amounts of freedom further downstream, either for animators to interact with parts of buildings, or for the VFX team to blow up entire city blocks!