Case Study: The Crash

Dynamic Simulation & Material Properties

The primary challenge of this project was to simulate a realistic car crash by modeling structural steel sheet metal deformations, glass shattering, and fiberglass fracturing. Unlike standard rigid body dynamics, this workflow utilized physical material properties to govern plastic deformation, bending limits, and fracture thresholds.

The vehicle geometry was pre-fractured and rigged with custom constraints. RayFire and physics solvers calculated collision impacts. This ensured that high-impact areas crumpled and folded into realistic metal wrinkles rather than shattering like brittle glass.

Baking and Slow-Motion Retiming

To avoid high-speed interpenetrations and geometry collision errors, the physics simulation was calculated at 120 frames per second, with the collision solver sub-sampling the dynamics every 0.5 frames.

Once solved, the varying vertices coordinates from the metal deformations were baked into Alembic cache (.abc) containers to decouple simulation calculations from rendering loops. In post-production, a linear time retime of 20% of the original speed was applied, creating a dramatic, high-fidelity slow-motion sequence while interpolating vertex motion paths cleanly.

Deep Compositing Pipeline & 3D Bokeh

During the rendering phase, the scene was outputted as Deep Image EXRs to ensure seamless integration between the solid vehicle structure and volumetric FX passes (smoke, dust particles, and headlamp light beams). Deep images store multiple depth samples per pixel, eliminating traditional edge matting issues and artifact lines.

Motion blur was added post-render using 2D motion vectors. The deep depth samples allowed the compositing scripts to calculate three-dimensional coordinates in space, enabling the rendering of a physically accurate bokeh lens blur that filters realistically through the volume of light rays and dust particles.

Cinematic Aspect Ratio

The final composited sequence was cropped and framed to a wide 2.35:1 aspect ratio, mirroring the anamorphic widescreen formats popular in feature film productions.