Show a point cloud beside the model

What you'll do

Look at a laser scan of a building next to its model: check that what was built matches the design, measure between scanned points, and cut a thin slice to read walls, doors and columns from.

Steps

1. Open the cloud: Open a .las, .laz, .xyz or .pts file, or drop it on the page. With a model open, the cloud joins the model in the 3D view; opening a cloud never closes the model or its unsaved changes. Without a model, the cloud opens on its own.
2. The cloud bar appears under the toolbar. It says how many points show and how many the file has.
3. Choose Color by: the file's own colors (when the scanner stored them), Height, Intensity, Class (LiDAR classes such as ground, vegetation and building) or One color. Size makes the points bigger or smaller.
4. Click Plan under Slice to keep only a thin band 1.2 m above the lowest point, seen from the top: walls, door openings and columns read like a floor plan. Front and Side cut upright bands for elevations and sections. Move the band with At, and change Thickness (meters). Off shows the whole cloud again.
5. Click Measure in the toolbar. The pointer snaps to the cloud's points (the label says "point cloud"), so you can measure from wall to wall in the slice, or from a model element to the scan. A model corner or edge within reach still wins.
6. With Measure › Location, a cloud point gives its latitude and longitude from the cloud's own coordinate system, when the file names one.
7. Hide hides the cloud for a moment; Remove takes it out. Show › Point cloud hides or shows the bar.

Where the cloud goes

Place in the bar says how the cloud lines up with the model:

• Model coordinates: the cloud's numbers are the model's own (a scan registered to the design's coordinates).
• Map coordinates: the model has a map conversion (IfcMapConversion) and the cloud is in the same projected system: the cloud is placed through it. If the two name different systems, the status line says so.
• Centered on the model: when neither puts the cloud near the model, its middle goes on the model's middle and its lowest point on the model's floor. Pick another choice to override it.

When the file does not say its units, BimCraft reads meters and offers Units in the bar.

Trace the as-built lines

Click Trace in CadCraft to hand the cloud to the drafting app in a new tab. It opens there under the drawing, where a plan slice and object snap let you draw the walls over the scan. See the CadCraft topic on point clouds.

How many points

A scan can hold hundreds of millions of points. BimCraft reads every point once and keeps an even share of them to draw: Show in the bar sets how many (1, 2, 5 or 10 million). More points need more memory and a faster graphics card. Counts per LiDAR class are of every point in the file.