DXF and DWG underlays

An underlay sits under the model in plan. It is kept beside the model, not in it: importing or removing one is not an edit, has no undo step, and is not part of any conversation. The agent does not receive its lines.

Import a DXF, DWG or PDF

1. Choose Import Underlay… (⌥⌘U) and pick a .dxf, .dwg or .pdf.
2. For a DXF or DWG, pick the Units (prefilled when the file says them) and, if you like, an origin in metres. Click Import.
3. For a PDF, pick the Page, type the Scale as the sheet writes it (1/4"=1'-0", 1:100), and an origin where the page's lower-left corner lands. Click Import.

The import runs as a job with Cancel.

Limit. Released builds do not read DWG files yet: Studio asks you to convert the file to DXF first. DWG reading works only in development builds, until its reader is cleared for release.

Limit. A DWG that is password-protected, or older than AutoCAD 2000 (R14 and before), is refused with the reason.

Calibrate a PDF at an unknown scale

1. In the PDF dialog, click Calibrate. The page comes in at a provisional 1:1 and plan switches to Measure.
2. Click the two ends of a line whose real length you know.
3. Type the Real distance and apply. The page is imported again at the right scale.

A scanned page with no lines comes in as a picture at half opacity. It has nothing to snap to.

Work over it

• Plan draws each underlay in muted blue under the model; 3D does not draw it. Text is kept but not drawn.
• Layers (L) has an "Underlay <name>" checkbox for each one.
• While you draw, the pointer snaps to an underlay's endpoints and midpoints, and the cue says "Underlay endpoint" or "Underlay midpoint". Hold Shift to turn snapping off.
• Plan badges door, window and fixture symbols it recognises in the underlay (green, amber or red by confidence). Underlay symbols in Layers hides them.

Clip

Trace an underlay into rooms

1. Choose Trace Underlay to Rooms… (⌥⌘Z) and pick the underlay.
2. Studio reads it: closed shapes become rooms (named by a label inside them), gaps with a swing become door marks, gaps with glazing lines window marks. The result lands on a new conversation, "Traced from <name>", never on the base model.
3. Review the list in that conversation, lowest confidence first. Each row has its confidence and the reason, with Keep, Delete and Zoom. Plan outlines medium-confidence rows in amber and low-confidence rows dashed in red.
4. For a door or window row, pick its type, or a new type sized from the mark. Apply to all like this gives the same type to every mark from the same block; a row below high confidence joins only when its Include box is ticked.
5. Fixtures it recognised are listed as not placed.
6. Accept the conversation, then run Make Walls to turn the rooms and marks into walls, slabs, doors and windows. See The handoff to BIM.

Remove an underlay

Choose Remove Underlay… (⌥⌘Y) and pick it. The file on your disk is not touched.