Point clouds (drone and scan)

Overview

Open a LAS or LAZ file from a drone survey or a scanner, look at all of it, clean it, sort it into ground, vegetation and buildings, and build the ground and the contours from the points that really are ground. The file is never changed, and nothing leaves your computer: the cloud is cut into tiles that are kept in this browser's own storage, or in a folder you choose.

The cloud is shown from the coarse tiles first and refines as you move closer, within a point budget you set, so a very large file can be inspected without loading it all. Cleaning is an edit log on top of the file (crop, delete, change class, find noise), so every step undoes. The ground you build goes into the CivilCraft project as Existing ground, the same way a LAS import does, so contours, sections, grading and volumes work on it at once. The numbers it reports (how far the points sit from the ground, how much a pile holds) are numbers from your data, not a certificate.

Who it’s for

• A surveyor or engineer who flew a drone and needs an existing-ground surface and contours from the photogrammetry points.
• A site manager who wants the volume of a stockpile, or how much earth moved between two flights.
• A landscape architect or civil designer who wants to see a scanned site, and to take out the trees and buildings before using the ground.
• Anyone who has a LAS or LAZ file that is too big to open whole and wants to look before deciding what to keep.

What you can do

• Open a LAS or LAZ file and see what it holds and how much room a build needs before it starts. Find it in the Point clouds tab, Open a cloud.
• Look at the whole cloud, refining as you zoom, coloured by file colour, height, class, intensity or residual, with eye-dome lighting and points that shrink with distance. Point clouds tab, Look; the 3D view and the plan both show it.
• Clean it: lasso, box or polygon, then delete, change the class, restore or crop; the count is shown before you apply, and Undo and Redo walk the edit log. Point clouds tab, Clean.
• Find stray points (noise) and mark them as low or high noise. Point clouds tab, Clean, Noise filter.
• Find the ground tile by tile, then sort the rest into low, medium and high vegetation and buildings. Point clouds tab, Classify.
• Build the existing ground from the ground points, see how far the points sit from it, fly to the ten places that differ most, and pick breaklines on the cloud in 3D or in the plan. Point clouds tab, Ground, checks and numbers.
• See the contours over the cloud before you keep them, in a small picture in the same tab.
• Work out a stockpile volume inside a boundary you draw against a base you choose, and the cut and fill between two flights, with a CSV. Point clouds tab, Stockpile volume and Flight to flight.
• Save the cleaned and classified cloud as a LAS 1.4 file; a very large cloud is written to the file as it goes. Point clouds tab, Export.
• Keep the clouds in a folder you choose instead of the browser's storage. Point clouds tab, Clouds on this computer.

Methods and standards

The cloud is cut into a tiled octree with additive levels of detail: each tile holds the points on its own grid, its children hold the rest, so drawing a tile and its ancestors draws every point exactly once. Positions are stored as integers on a millimetre grid, so a point read back is the point read in. Cleaning is a log of edits (crop, delete, class, noise, ground) applied to each tile when it is read; the source tiles are never rewritten.

Ground is found tile by tile (256 m tiles with an overlap) with a progressive morphological filter (after Zhang and others, 2003, our own code): the lowest point in each grid cell, an opening that grows its window while the slope allows, then every point is compared with the ground grid and called ground within a tolerance (0.15 m, or 0.08 m on the survey-grade switch). Vegetation and buildings are told apart geometrically, from height above the ground and how flat the neighbourhood of a point is; there is no machine learning. Stray points are found by counting neighbours, or by the distance to the nearest ones.

The ground surface is built by CivilCraft's own constrained Delaunay TIN (the same code the LAS import uses), from the ground points thinned to one per cell. A stockpile is the volume of the surface above a base inside the boundary; the base is the lowest boundary point, a plane, a smooth curved surface or a TIN through the boundary, or a level you type. Samples on the boundary that stand above a robust fit (a tree on the line) are left out of the base. Cut and fill between two flights is computed on a grid of cells (default 1 m).

Data and sources

It ships no data. It reads the file you open (LAS 1.0 to 1.4, LAZ) and keeps tiles of it where you choose. The coordinate system and units are those of the file: the cloud is taken to be in the project's system, in metres, and the add-on does not reproject it. Colours, intensity and classes come from the file when it has them.

Verification

Limits

It is a design aid, not an approval, and the numbers are not a certificate: the registered professional decides what the ground, the contours and the volumes are worth. It has been tested on a made-up 300 m site and on made-up files only; no real drone survey has been tried yet, so the settings are tuned on that and may need changing for your site. It does not draw point-by-point selections in 3D exactly (an outline in 3D is a vertical prism; use the plan or the top view when it has to be exact). It does not read E57, PLY, PCD, PTX or XYZ, or several files of one flight as one cloud, reproject a cloud, write LAZ point formats 1 and 3 or 6 to 10 (the LAZ it writes is format 0, or 2 with colour, classes 0 to 31), or read Autodesk's RCP and RCS files. It does not make surfaces from photographs, colour a cloud from photos, or find poles, kerbs and pipes. A browser without folder access keeps clouds in its own storage, whose size the browser limits.

Files and formats

Reads LAS 1.0 to 1.4 and LAZ. Writes a cleaned, classified LAS 1.4 (point format 6, or 7 with colour; the coordinate system is written in the file) or LAZ (point format 0, or 2 with colour, in a LAS 1.4 file, compressed without loss by CadCraft's own compressor) and CSV tables for volumes. The ground goes into the project as survey points, and from there out through CivilCraft's own exports (LandXML, DXF, IFC, GeoTIFF). The project does not yet remember which cloud it used.

Get started

1. Switch the add-on on in Settings, Add-ons, then open the Point clouds tab and choose your LAS or LAZ file; press Build the cloud.
2. Look at it, clean it with the lasso, then Find noise, Find the ground and Classify vegetation and buildings.
3. Press Build ground; read the numbers, then Show contours, or draw a boundary round a pile for its volume.

Languages

The text is available in:

• Afrikaans (af)
• Amharic (am)
• Arabic (ar)
• Azerbaijani (az)
• Belarusian (be)
• Bulgarian (bg)
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• Bosnian (bs)
• Catalan (ca)
• Czech (cs)
• Danish (da)
• German (de)
• Dhivehi (dv)
• Greek (el)
• English (en)
• Spanish (Spain) (es-ES)
• Spanish (Mexico) (es-MX)
• Estonian (et)
• Persian (fa)
• Finnish (fi)
• Filipino (fil)
• French (fr)
• Galician (gl)
• Guarani (gn)
• Hebrew (he)
• Hindi (hi)
• Croatian (hr)
• Hungarian (hu)
• Armenian (hy)
• Indonesian (id)
• Icelandic (is)
• Italian (it)
• Japanese (ja)
• Georgian (ka)
• Kazakh (kk)
• Khmer (km)
• Korean (ko)
• Kyrgyz (ky)
• Lao (lo)
• Lithuanian (lt)

Works in

Comes with

Nothing else.

Versions

Licence and maker

CadCraft (CadCraft, first-party). Licence: Apache-2.0. Dependencies carry their own licences, listed on their pages.