Model from a scan

What you'll do

Draw an existing building from its laser scan: walls where the scan shows them, on the right level, square to each other.

Steps

1. A building to draw in. File › New building, with as many levels as the building has (you can add levels later, see The site, the building on it, and its levels). Draw turns on.
2. The scan. Show › Point cloud and choose the file (LAS, LAZ, E57, PLY, PCD, PTX or XYZ: see Show a point cloud beside the model). The cloud shows in the 3D view, and the plan shows its slice: the scanned points 1200 mm (4 feet) above the level, as dots. That is the height where walls, doors and windows read best.
3. Line it up with the level. Open the model bar's Scan menu and click Align its floor to this level: the cloud moves up or down until the floor it scanned sits on the level shown. Check the slice now cuts through the walls.
4. Square to the building. Scan › Turn it square to the building turns the cloud so the walls in its slice run along the plan's axes, so walls you draw with ⇧Shift held line up with the scan. It turns about the middle of the walls it found, so trees or a neighbour's wall caught in the slice don't swing the scan away. Align the floor first: the slice then cuts through the walls.
5. Trace the walls. Choose Wall and click along the dots: the tool snaps to scanned points (the snap mark is a small diamond) as well as to the walls you have drawn. A wall is drawn on its center line, so click along the middle of the two rows of dots a wall leaves; type its thickness by choosing the wall type first. Then add the doors and windows where the slice shows the gaps.
6. The next level. Choose the level above in the plan's level list: the slice follows the level's cut height. Align the floor to that level again only if the scan's floors are not where your levels are.

What you should see

• The slice changes as you change level, and a thicker slice (Scan › Slice thickness) shows more points where a scan is thin.
• Scan › Undo the alignment puts the cloud back where it was placed when it opened. Aligning moves the cloud in the view only: it is not saved in the IFC file, and walls you have drawn stay put. The alignment goes with the cloud when you change Place or Units, or open another model.
• Scan › Show the slice on the plan hides or shows the dots.