Engineer a truss within a tight budget, read the forces flowing through each member, then call your weakest link before the load comes down.
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How to play
Each round is a build-predict-test loop. You spend a budget upgrading members from cheap to strong, study a live free-body view, name the member you think fails first, and then run the load test to see if your bridge holds.
Build: click members to cycle each one's capacity, spending against your budget.
Read the free-body colours, red marks compression, blue marks tension, with intensity by stress.
Predict: click the member you believe will fail first.
Test: the load runs and you're graded on whether the span holds and whether your prediction was right.
Controls
Desktop: click members to upgrade them, click your predicted weak member, then run the test; pick Short/Medium/Long and Daily/Practice.
Phone & tablet: tap members and buttons, fully touch-friendly.
Tips & strategy
The deepest-stressed member shows the strongest colour, that's your prime suspect for first failure.
Don't gold-plate: strengthening members that carry little force just wastes budget.
Triangulated load paths spread force; a long unbraced span concentrates it and fails early.
What you'll learn
Spanwright models a real truss with axial tension and compression, then asks you to build it and predict its failure.
Skills: structural engineering, trusses, tension and compression, statics
Best for: advanced high school / college
For parents & teachers: real truss statics.
Origins
A build-predict-test loop where you name the member you think fails first, with a live free-body diagram to study, is structural analysis with an explicit prediction.
Requiring the prediction before the test is the original design.
Naming the failure point is the engineering skill. A structure that holds tells you little; knowing in advance which member is critical is what lets you spend the budget where it matters, and a free-body diagram is the tool that makes it derivable rather than guessed.
About Spanwright
Spanwright models a real truss with axial tension and compression, then asks you to both build it and forecast its failure. It's an original, free browser game with three span sizes and daily plus practice modes.
A free, original browser game on PlayPendium. No download, no install.
