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Try a range of tolerances and show which ones the lattice reads the same way.

Category: Combine | Add menu: Combine > Stability Sweep

The second diagnostic, and the one to run first. Weave has a Tol input that decides how close two curve ends have to be before they count as the same meeting point, and the right value is a property of your lattice, not a number anybody can tell you. This node finds it.

Set the tolerance far too small and every pair of ends that ought to be one meeting point stays two, so the lattice comes back with far more meeting points than it has crossings. Set it far too large and separate crossings get swallowed into each other, so the count collapses. In between there is usually a range where the count does not move at all, however much you change the tolerance, because within that range the lattice reads exactly one way.

That flat stretch is the plateau, and a value from the middle of it is the one to use. A plateau also tells you the lattice is sound: a drawing with no flat stretch anywhere is one whose crossings genuinely are ambiguous, which is worth knowing before you weave it.

Like the other two weave nodes, this one has a Calculate button and does nothing until you press it. The result is parked, is not saved in the document, and needs the desktop app.

• Calculate (trigger): the button.
• Geometry (any): the lattice, broken at its crossings by Split Curves.
• Tol Min (number, editable, 0.001): the smallest tolerance to try. Must be zero or more.
• Tol Max (number, editable, 1): the largest. Must be greater than Tol Min.
• Steps (number, editable, 24): how many tolerances to try across that range, at least 2. Each step is a full pass over the lattice, so the count is capped at 500; a plateau shows up in tens of steps, not hundreds, and the default is plenty for most patterns.

• Tol -> Nodes (point): the plot. One point per step, with the tolerance across and the count up. Feed it to a Realize node and read the shape: the plateau is the flat run.
• Report (string): the same pairs as text, with a line saying how many steps ran and the range of counts they produced.

The Report calls the meeting points nodes, which is the solver's own word for them. They have nothing to do with the nodes in the node graph.

1. Wire the lattice into both this node and Weave.
2. Sweep. Look for the flat run.
3. Take a value from the middle of it and type that into Weave's Tol.
4. If there is no flat run, widen Tol Min and Tol Max and sweep again before concluding anything. A plateau outside the range you tried looks exactly like no plateau at all.

Worth repeating, because it saves the most time: a weave that comes back with a run of parallelogram fallbacks instead of curve-true shadows is nearly always a Tol problem, and this is the node that settles it.

< Previous: Crossing Census | Next: Data >

• Weave: what the tolerance is for.
• Crossing Census: the other diagnostic, crossing by crossing.
• Split Curves: the pass that has to run before the sweep means anything.