Opening overlap prevention

VisionPlan won't let two openings overlap on the same wall. A door, window, or cased opening occupies a span of wall — the opening width plus the trim casing on either side — and that span has to be clear of every other opening on the same wall before the placement commits.

This article covers why the rule exists, what you'll see when it triggers, and how each placement path (click, drag, duplicate) handles it.

Why the rule exists

Real construction can't put two openings on the same span. A second door inside a doorway isn't a thing. A window framed inside a window frame isn't a thing. The overlap check makes accidental misplacements impossible to commit — the alternative was contractors discovering the bad geometry only after exporting to print.

What counts as overlap

Two openings overlap when their wall-position spans (including trim on both sides) touch or cross. The check compares:

• The candidate opening's centre position on the wall, plus half its total width (opening width + 2 × trim width) on either side.
• Every other opening on the same wall, with the same width-plus-trim span.

Openings on different walls never overlap each other, even when the walls share a corner.

How each placement path handles it

The rule applies to four entry points. Each one handles a blocked placement differently.

Click-place through the dialog

When you click a wall with the Door / Window / Opening tool and press Place in the dialog, the editor checks the candidate opening against every existing opening on that wall. If the span overlaps, the dialog stays open and a snackbar appears at the bottom of the screen:

Cannot place Door — overlaps an existing opening on this wall

(The opening type in the message matches the active tool — Door, Window, or Opening.)

To recover, change either the Width (a narrower span might fit) or move the click position by closing the dialog and clicking again at a different spot on the wall.

Shift+click fast-path placement

When you hold Shift and click a wall to skip the dialog, the same check runs against the persisted defaults. If those defaults would overlap, the placement is rejected with the same snackbar — no opening is added.

Dragging an existing opening along a wall

Drag handles overlap differently from placement. Instead of rejecting outright, the dragged opening slides past any blocker on its current wall when the cursor crosses to the other side.

The algorithm at a glance:

1. The drag projects the cursor onto the nearest wall.
2. If the candidate position overlaps a blocker, the opening snaps to the gap on whichever side of the blocker the cursor is currently nearest, with a tiny visual gap so the trim doesn't kiss.
3. If both sides of the blocker are unavailable (another opening is too close), the drag tries the next blocker further out, up to four blockers deep.
4. If neither side ever clears, the opening stays at its last valid position — the drag effectively stalls until you move the cursor somewhere that has room.

Dragging past a corner onto an adjacent wall

When the dragged opening's wall is packed near a corner — no gap on either side, and the cursor is close to the shared endpoint — the drag tries to hop the opening onto an adjacent wall that shares that corner. The opening lands in the nearest free slot on the adjacent wall.

Without this, a door would stall at the wall end until the cursor moved well past the corner. With it, the door rounds the corner smoothly.

Duplicate from the context menu

When you right-click an opening and pick Duplicate, the editor searches outward along the same wall for the nearest free gap. It probes in 0.05 (5%) steps along the wall in both directions, accepting the first candidate position that doesn't overlap any existing opening.

If no slot exists anywhere on the wall — the wall is fully packed — the duplicate is rejected with the same overlap snackbar. To get a copy onto a different wall, place a fresh opening with the tool instead.

How to fix a blocked placement

When the snackbar appears:

• Narrow the opening. A 24" door fits where a 36" door doesn't. Reopen the dialog with a smaller width.
• Move farther down the wall. Click a different point — the snap range gives some forgiveness but not unlimited.
• Split the wall first. Right-click the wall and pick Split Wall to make two segments, then place each opening on its own segment. See Wall context menu.
• Delete one of the existing openings if you actually meant to replace it.
• Use two separate walls for a back-to-back assembly. Walls are single line segments in the editor — there's no "front" or "back" face — so two openings on the same wall always share the wall's length. For a thick wall assembly that needs an opening on each face in the real world, model it as two walls (one per face) with the appropriate gap between them.

Tips

• The drag-slide-past behaviour is one-directional per move. If you drag past a blocker, then drag back through it, the opening slides past the same blocker the other way.
• The 4-blocker depth cap on drag is enough for any realistic wall — walls with more than four openings in a row are uncommon, and the slide algorithm covers everything up to that.
• The corner-hop tolerance is about 2 feet from the shared endpoint. If the cursor is more than 2 feet from a corner, the drag treats the current wall as the only option.
• The visual gap left between adjacent openings after a slide is intentionally tiny — just enough that the trim outlines don't kiss. It's not a placement constraint you can tune; it's a render hint that the openings are distinct.