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Tree dynamics lab

Interactive 3D tree-felling physics simulator

Tree LabTREE MODEL READYGuided tutorial ↗
Ready for frame 01
01 Face cut 1 · entry 100% aligned Place the bar flat at four feet with its bottom chain rail at the front bark. The sight line on top points with the lean (+Z).
04Lean
CENTER
05Fall TIMBER!!!
Growing model tree Loading the 3D physics scene…

The model tree is standing with a 4.6 degree growth lean toward the authored positive Z fall corridor. The first of six saw keyframes is ready.

Run sequence
Custom cut workflow Tutorial →

Chainsaw controls

Interlocked
0%

Each planned stage must be run in order. Gas Trigger advances the current path only while pressed. Auto Saw advances it automatically until the stage completes or the bar is pinched. A plunge trigger cut automatically finishes through to its rear-exit frame after tree motion begins; a straight-through cut stops and withdraws at motion onset.

Fall playback

Deterministic timeline
Growth lean4.6° +Z Fall corridor+Z / AUTHORED
Center of mass5.15 M Fall angle0.0° Bar / base Ø81 CM / 78 CM Plate / kerf6.5 / 9.0 MM
Camera-relative XYZ

Persistent orthographic tree diagnostics

Face +ZFall-side elevation
Face positive Z diagnostic. Shows the fall-side face cut, active chain rails, hinge width, and trunk profile.

Notch width · rail paths · holding edge

Side −XPerpendicular to lean
Side negative X diagnostic. Shows growth lean, face closure, stump gap, hinge rotation, and fall trajectory.

Lean plane · stump gap · contact

Rear -ZLooking with the lean
Rear negative Z diagnostic. Shows the back-cut chain rail, remaining holding wood, and positive Z fall direction.

Back cut · remaining wood · +Z corridor

Move Camera · WASD to fly · Shift to boost · drag to orbit · wheel to zoom fall vector mass / force holding wood
02

Face-cut validation

Make the two planes meet.

Top-down stump sectionPLANNED FACE
Waiting for four face keyframesLock entry and apex poses for both planes.
Notch depth
—
Cross-trunk cut width
—
Opening
—
Apex mismatch
—

Educational reference: 30% of trunk diameter sits within the OSHA Logging eTool’s 25–33% face-notch depth range. Exact geometry varies; this is not a universal prescription. OSHA eTool source ↗

Physics model · motion onset

Why the tree starts moving.

Overturning demandMgravity = mass × g × horizontal COM offset
Wood resistanceRemaining area × section shape × effective fiber strength
Motion thresholdTree moves when demand approximately reaches the remaining resistance
01 · MASS + BALANCE

Weight is distributed, not concentrated.

The model divides the tapered trunk into 64 volume slices, then adds modeled limb and crown mass. Their combined center of mass determines the horizontal lever arm acting around the remaining hinge.

02 · LEAN + LEVERAGE

More forward lean raises the turning moment.

Gravity always points down. Lean and crown bias move the center of mass farther toward the fall corridor, increasing the moment at the stump. With the same cuts and wood condition, a larger forward lean should reach motion onset sooner.

03 · HINGE + TRIGGER

Uncut wood carries the load until fibers yield.

The green hinge is the uncut band that bends and guides rotation. This preset targets hinge thickness near 10% of tree width at the cut. In a plunge plan, the yellow band is the bored slot; after motion onset the chain finishes through the rear trigger instead of depicting it as splintered wood.

04 · FAILURE + CONTACT

Fracture is progressive, then collision takes over.

Each incremental cut removes cells from a 96 × 96 stump section. The solver compares gravity demand with reduced section and trigger capacity, refines the threshold by bisection, and integrates hinge damage, stump contact, butt separation, and ground impact. Straight-through motion stops and withdraws the saw; plunge-trigger motion completes the locked cutting path.

Model boundary: this is an educational rotating-body and idealized-fiber simulation, not a felling prediction. Real behavior also depends on wind, moisture, grain direction, knots, decay, root and soil condition, hidden defects, cut quality, and the flexible response of the crown. Reference values and terminology: OSHA felling hinge, OSHA special techniques, USDA FPL black locust data, and the FPL Wood Handbook.