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Predict how the tolerances on individual features stack up across an assembly. Build the dimension chain (1D) or hole-alignment pattern (2D) and check the result against spec by worst-case, RSS, and Monte Carlo.
A tolerance stack-up combines the variation of every part and feature that controls a functional requirement (a gap, a fit, an alignment) to predict whether the assembled result stays within spec. Instead of judging each tolerance in isolation, you add their effects along a dimension chain.
This tool runs two modes: 1D linear stacks (dimensions along a single axis) and 2D hole-alignment / fastener-clearance checks (positional tolerances in a plane).
Worst case sums every tolerance at its extreme: conservative, for safety-critical features. RSS (root-sum-square) treats contributors as independent normal distributions and reports nominal ±3σ, realistic for controlled processes. Monte Carlo simulates 10,000 assemblies from the distribution you assign each contributor and reports the actual yield against spec.
Reference: ASME Y14.5 (GD&T) for the positional-tolerance framework; RSS and Monte Carlo follow standard statistical tolerance-analysis practice. Preliminary / convenience use; verify against your governing spec before design release.
Minimum acceptable value.
Optional nominal target.
Maximum acceptable value.
tolerancing · tolerance stack-up · tolerance stack · tolerance analysis · 1D stack · 2D · 2D hole alignment · hole alignment · pin fit · shaft fit · fixed fastener · floating fastener · clearance hole · bolt hole · fastener tolerance · STEP · CAD assist · CAD upload · CAD preview · 3D viewer · assembly · model context · model preview · worst case · RSS · Monte Carlo · root sum square · clearance · assembly fit · GD&T · manufacturing · dimension chain · plus minus tolerance