A crane's rated capacity is never a single number — it is a curve that falls as the hook moves farther from the pivot. This model reconstructs a mobile crane's boom, counterweight, and outrigger base in 3D and computes the real overturning physics live: load moment versus resisting moment, checked against the tipping line at the front outriggers.
Real cranes rarely fail from the load being "too heavy" in absolute terms — they fail from operators exceeding the charted capacity at a given radius. Modern cranes carry Rated Capacity Indicators that compute this same moment balance in real time and cut hoisting power before the tipping line is reached.
A 3D mobile crane whose rated capacity falls as its boom swings out to greater radius — balance load, counterweight, and boom geometry against the tipping line without ever exceeding the safe moment.
Load moment (weight × radius) must stay below the resisting moment supplied by the counterweight and base, or the crane rotates about its tipping line — the same statics that govern every real crane's load chart.
Adjust load mass, boom angle, boom length, and counterweight. Watch the radius, load moment, resisting moment, and margin update live, and see the crane visibly lean once the tipping line is crossed.
Most real crane tip-overs happen not because a load was absurdly heavy, but because the operator exceeded the charted capacity for that specific radius — the same "moment budget" this simulation makes visible.