Deep Dive
Setting up trace and optical flow basics
Bileam starts by dropping a trace POP on a bird video input, explaining it converts 2D images into 3D point data. He immediately notes the raw output looks flat and flickery. To solve this, he chains an optical flow operator upstream, which only traces moving pixels. He cranks optical flow's force to 50 and adds a small threshold of 0.05. The result is much cleaner—only the bird traces into space, not the static background. To further smooth out the remaining flicker, he builds a feedback loop: monochrome TOP feeds into a feedback TOP at 95% opacity, composited back into itself. This classic pattern eliminates jitter and creates seamless motion trails.
Three aesthetic approaches with trace modes
Bileam sets up three different trace styles by switching between modes. First, he keeps resolution low (0.05) and threshold at 0.05, then bumps smooth edge distance to 0.24 to create abstract circular outlines around the bird. He adds a triangulate POP afterward to connect all points with lines, giving it sketch-like character. For variation, he adds a second trace via a switch, this time raising threshold to 0.65 and changing mode to smaller equal, then applies another triangulate. The third approach changes trace output to bricked surface, which generates dense volumetric geometry packed with data. He demonstrates switching between all three on the dancer footage, showing how each mode reveals different visual qualities—abstract to detailed to fully surfaced.
Performance tuning and 3D expansion
Resolution is the performance lever Bileam keeps hammering. He shows that 0.5 generates 90,000 points while 0.043 yields only 800—a massive range affecting both visuals and frame rate. For the dancer clip using optical flow, he adds a 0.05 threshold to the flow itself so it only picks up primary motion, not noise on the edges. When performance tanks, dial resolution down. Near the end, he adds an extrude POP to the trace output, converting line geometry into actual 3D mesh you could render with PBR materials. He aligns the Z origin so the extruded shape centers properly at zero. This opens a whole separate workflow: trace becomes a volumetric sculpture rather than just sketch lines, expandable into full environment geometry.
Render setup and layout composition
Bileam builds a render network with geometry, camera set to orthographic (1 unit width, no perspective distortion), line material, and low-res output matching the original aspect ratio. He uses a transform with black background and composites the traced render over the original via an over TOP. Then he creates a layout with three inputs—original, composited, and traced—arranged vertically at 1080x1920 resolution with grid rows mode. He scales down slightly and adds black background null for clean presentation. This layout approach lets him show all three versions side-by-side, making it easy to see how threshold and resolution choices change the final look. The orthographic camera is key: it perfectly aligns 3D space with the 2D video without perspective warping.