Hierarchical N-body solver LIVE

Fast Multipole Gravity Lab

Softened Newtonian gravity on an adaptive quadtree. Cartesian multipole moments become Taylor-expanded local fields for distant cells, and nearby leaves are summed exactly.

M2M → M2L → L2L → P2P

Particles–

FPS–

FMM solve–

Tree nodes–

M2L–

Force error–

Scene

Particles

FMM solver

Expansion order p

Separation ratio

Leaf capacity

Solver pipeline–

TREEadaptive quadtree build––

M2Mchild moments → parents––

M2Lfar cells → local fields––

L2Lparent fields → leaves––

P2Pexact neighboring forces––

Physics

Gravity G

Softening ε

Timestep Δt

View

Particle trails Quadtree overlay Acceleration vectors Automatic sampled error

Click to inject a particle cloud · Shift-click to add a massive body · Space pauses