Diagnosing Sketches: Over-Constrained Conflicts and Validation

Two things can go wrong with a sketch that a clean DOF count won't tell you about: you can add too many constraints (over-constrained), or you can leave behind bad geometry — tiny stray lines, gaps, duplicates, crossings — that a later export or trim will choke on. Pingendum has a tool for each: live conflict flagging in the Constraints panel, and the Validate Sketch checker.

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Prerequisites

Before you begin, ensure that:

• You've completed Constraining a Sketch and understand the DOF indicator.
• You've read Reference (Driven) Dimensions, since the conflict policy described there is what governs a typed value that would over-constrain the sketch.

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Part 1 — Over-Constrained Sketches

A sketch is over-constrained when it carries more constraints than it has freedom to satisfy — for example, two different Length dimensions on the same line, each demanding a different value. The solver can't honour both, so it flags the conflict rather than silently picking one.

Recognizing it

Over-constraint is reported by Validate Sketch, covered in Part 2 below — there is no live constraints panel in this build, and no badge or per-row pill.

Run the checker and it reports one of two things at the top of its list:

• Over-constrained: N redundant constraint(s) — the constraints don't contradict each other, but some restate what the others already fix. The sketch still solves, and its geometry is correct.
• Conflicting constraints — the constraints are directly incompatible. This is the more serious of the two.

Beneath either, each offending constraint gets its own Redundant constraint row, so you can act on them one at a time rather than guessing which of them is at fault.

The two ways to fix it

After either, re-run the checker to confirm the report is clean.

Note

Earlier builds offered a third fix — ticking a ref checkbox to turn a conflicting dimension into a reference dimension. That checkbox no longer exists. Converting to a driven dimension is now only reachable through the numeric input's conflict policy, and only at the moment you type a conflicting value; see Reference (Driven) Dimensions.

Worked example

1. Draw a line and apply a Length dimension (say, 50).
2. Apply a second Length dimension to the same line with a different value (say, 70).
3. Run Drawing → Validate drawing. The report opens with Over-constrained: 1 redundant constraint(s), followed by a Redundant constraint row for the surplus dimension.
4. Resolve it either way:
   • Select the row and apply the Delete redundant constraint repair; or
   • Press Ctrl+Z to undo the second dimension entirely.

Tip

Undo is the gentlest fix when you've just caused the conflict — it removes exactly the constraint you added, with no judgement needed about which of the flagged rows is really at fault.

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Part 2 — Validate Sketch

Where over-constraint is about constraints, Validate Sketch is about geometry. It scans the active sketch for problems that don't show up as a DOF number but will cause trouble downstream, and gives you a clickable list that jumps straight to each one.

Finding it

Drawing → Validate drawing. It's enabled whenever a drawing is open.

It runs two checks, not one

Validate drawing covers two different things, in order, and which one you see first depends on what it finds.

Pass 1 — the drawing as a document. Before touching any geometry, Pingendum checks the file's own structure: a missing identity, a sheet index pointing at nothing, an inverted drawing extent, display precision outside a sensible range, tolerances that would make the solver behave unpredictably. These survive a successful file load, which is why they get their own pass — they're the kind of thing a corrupt or hand-edited file gets wrong around the geometry.

• Nothing wrong? You'll see "The drawing itself is valid." in the status bar and go straight to Pass 2. Most of the time this is all you notice.
• Something wrong? A Validate Drawing dialog appears first, saying how many errors and warnings were found. Expand its details for the full report, then choose:

Not every document issue is repairable — where guessing at a fix would mean inventing data, it's reported and left alone.

Pass 2 — the geometry. This is the Validate Sketch panel, and it's what the rest of this section is about.

Note

The menu item reads "Validate drawing", but the geometry panel it opens is titled Validate Sketch. They belong to the same command.

What it checks

Using it

1. Open Drawing → Validate drawing.
2. A panel lists every issue found, coloured by severity (Error red, Warning amber, Info grey), with a summary count at the top.
3. Click any issue — Pingendum selects the offending geometry in the sketch, so you can see exactly which entities are at fault. This matters most for problems you can't see, like a duplicate line sitting exactly on top of the original.
4. If the issue has a one-click fix, a repair button appears beneath the list. Click it and the problem is corrected in place; the list re-runs itself immediately, so the row disappears and the summary count drops.
5. Re-validate re-runs every check against the current geometry — useful after editing the sketch behind the panel.
6. Save Report… writes the whole list to a file, which is worth doing before a handover or when you want to work through the issues away from the screen.

The repair buttons

Not every issue has one, but the common ones do:

Each repair is a single undo step, so Ctrl+Z reverts it cleanly if it wasn't what you wanted.

Note: clicking a row can shift the view

Selecting an issue changes which constraint buttons are enabled, and that can nudge the view — your geometry may appear to slide by a few pixels. It's cosmetic; nothing has moved in the sketch. Re-frame with F if it bothers you, but click the row again afterward, since clicking in the viewport clears the selection.

Result

A clean sketch reports "No issues found — sketch is valid." A sketch with problems gives you a navigable checklist; working top to bottom and re-running until it's clean is a good habit before you export or plot a drawing.

Note

The panel is modeless — you can leave it open and keep editing the sketch behind it. After edits, press Re-validate so the list reflects the current geometry.

Warning

Self-intersection detection currently covers straight segments. A profile that crosses itself only through arcs or splines may not be flagged here.

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Next Steps

You now know how to:

• Recognize an over-constrained sketch from the validation report
• Tell a redundant constraint apart from a directly conflicting one
• Resolve a conflict by deleting the flagged constraint or undoing it
• Run Validate drawing to find degenerate geometry, open contours, gaps, duplicates, and self-intersections
• Click an issue to select the geometry causing it
• Apply a one-click repair, re-run the checks with Re-validate, and save the report to a file

The next chapter steps back from problems and covers how a healthy sketch communicates — the colours Pingendum uses to show you, at a glance, what's constrained and what's selected.

Next: When a Sketch Won't Solve