Cleaning an exploded-conversion plan without breaking it
A 2,400-object mechanical plan arrives from a consultant as a DWG produced by exploding a PDF conversion. Every partition edge is drawn twice - sometimes offset by 0.02 mm - and the duplicates are scattered across five different layers. Your job is to (a) clean the working file enough to dimension it, (b) lengthen one wall run by 600 mm without disturbing the door opening inside it, and (c) add a repeated bolt pattern along a curved beam whose radius will change twice more before issue.
1. You select a partition line, press Delete, and the line is still there. Explain the symptom and lay out a cleanup approach, including what could go wrong with it.
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The symptom. The overlapping primitives are separate objects. Erasing one of two coincident lines leaves its twin, on screen and in the next selection. Any manual cleanup by clicking is therefore unworkable at 2,400 objects.
Approach. Keep the received DWG as an untouched reference (xref it or archive it read-only) and clean a working copy you own, so a re-issue can be compared against your version.
Run OVERKILL as a first pass: it deletes exact duplicates and can join collinear segments. Set a tolerance of about 0.05 - comfortably above the 0.02 conversion offset, far below any real feature gap on a mechanical plan. Run it layer by layer for the first pass rather than across everything, because the result is easier to review and undo.
What can go wrong. OVERKILL will merge collinear segments you wanted separate for dimensioning, and it will happily remove intentional overlap. Its output is not reversible in judgement terms: Save a checkpoint or work on a copy. Follow with QSELECT on Layer to sweep leftovers.
Sequencing. Dimension after cleanup, never before. Dimensions placed on geometry that is still duplicated survive every later edit and quietly double up.
2. For the 600 mm wall lengthening, compare grip editing with STRETCH, and state exactly what your selection window must and must not contain.
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Grips. The midpoint grip moves the whole line. An endpoint grip changes length for that line only - so if the wall is two parallel lines plus a hatch, grip-editing one line tears the assembly apart and leaves the hatch behind.
STRETCH is the right tool because it distinguishes objects inside the crossing window (moved wholesale) from objects crossed by it (endpoints inside move, endpoints outside stay).
The window decides the result. Draw a crossing window enclosing the two wall-line ends and the hatch edge at the lengthening end, and deliberately excluding the door block. Blocks are never stretched; a block moves only if its insertion point falls inside the window. Enclosing the door entirely moves the opening; crossing it does nothing useful.
Displacement. Turn Ortho on and type 600 rather than snapping to something that may be 0.02 mm off. Verify with DIST along both wall faces, and confirm the opening dimension is unchanged before saving.
3. The curved beam radius will change twice more. What is the right way to place the bolt pattern, and what should you watch for?
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Use ARRAY (Path), not COPY or a static copy array. A copied set bakes in both count and spacing; every radius change means redoing the operation and silently changing the count.
Method matters more than the command.
- Divide fixes the count and lets spacing float - correct when the number of bolts is a specification (say, an even number around a flange).
- Measure fixes spacing and lets the count change - correct when bolt pitch is the specification, which is the usual mechanical case. Set a spacing and a minimum, then let the count follow the arc.
Keep it associative (ARRAYASSOCIATIVITY = 1, the default) so a grip edit on the arc's radius updates the array. Confirm the path is the actual arc and not a polyline approximation, or the update will not track the change. Be aware that exploding the array later destroys the link permanently - and if a drafter explodes it 'to make it easier to edit', that is the moment the pattern stops tracking the beam.
Build the array once and copy it to repeated beams.