This 2D engine looks straight down on a patch of tissue and solves the full planar diffusion-clearance PDE on a 150×110 finite-difference grid (not a projection of the 3D model — a genuinely separate 2D Cartesian solve):
∂C/∂t = D·(∂²C/∂x² + ∂²C/∂y²) − k·C
Each cell is updated every sub-step from its 4 neighbours (5-point Laplacian), with the domain edges acting as an absorbing boundary (systemic clearance far from the bite). Because the equation is linear, multiple bites superpose exactly — click anywhere to add another venom deposit and watch two spreading fields merge.
- Diffusion coefficient D and clearance rate k — same physical meaning as the 3D model, tuned independently here.
- Tissue density — scales the effective diffusivity Deff = D / density, as denser tissue slows molecular spread.
- Antivenom — instantly neutralises part of the field everywhere and raises the clearance rate afterward.
Click the canvas to place a bite / add venom there. Drag to pan the view, scroll to zoom.