Point Cloud support

Point cloud (Wikipedia)
A point cloud is a set of data points in space. Point clouds are generally produced by 3D scanners, which measure many points on the external surfaces of objects around them.

VR Sketch can display a point cloud in addition to the usual SketchUp model. Assuming that you have a 3D scanner of some kind, you can use this feature to build a polygonal model equivalent from the real-space data. Note that you must send a SketchUp model to VR Sketch in order to display a point cloud; use an empty model if necessary.

In this documentation, we assume that you have already used a 3D scanner, and now you have a 3D point cloud in some file format---basically a list of points, typically containing many million points.

Various tools produce point clouds in various file formats. In order to use one of these with VR Sketch, you must first convert it to the POTree format. In this format, the data is split into many files, organized in a way suitable for rendering. If you have more than a few million points, the files are organized so that only a fraction are loaded and rendered at the same time, depending on your current position.

For now, VR Sketch only reads the XYZ position and the color of each point.

Rendering point clouds also works with Oculus Quest. The point cloud data is sent over the wireless connection as needed.

Conversion to LAS/LAZ format

LAS is a standard point cloud file format. LAZ files contain the same data but compressed.

If your point cloud is not in the LAS or LAZ format, the first step is to convert it to that format. (There is also the option to convert to a binary table; see the documentation of PotreeConverter for more details.)

We recommend using CloudCompare, which can import many of the existing file formats and convert them to LAS.

Here is a brief summary of the procedure:

  • Open your point cloud file with CloudCompare

  • Select it from the DB Tree list (list of loaded point clouds)

  • Click Save icon (or from menu File/Save)

  • Select the LAS format

  • You can choose the "Highest resolution" option and save as a LAS instead of a LAZ: compressing here is pointless, as the LAS is temporary anyway.

You cannot resize or reorient the point cloud in VR Sketch, so make sure it is the right way upwards and at the correct scale. Also, if the coordinates are very far off the origin, you may want to recenter it in this step. Indeed, a point cloud that is very far away from the origin will be very far away when you load it in VR Sketch, and difficult to find. (Moreover, there are precision issues: the coordinates are sent to the GPU as 32-bit numbers, which have only a precision of a few millimeters over 30km, or half a meter over 6000km.)

Convertion from LAS/LAZ to Potree

The next step is to use PotreeConverter: get its release 1.6. (There are more recent releases but VR Sketch may not support the newer formats.)

This is a command-line tool. In a Windows command-line console, type these lines (this assumes that D:\data\inputfile.las is the LAS file produced in the previous step; adapt as needed):

cd \Where\You\Unpacked\POTreeConverter

PotreeConverter.exe "D:\data\inputfile.las" -o "D:\data\potree_converted"

This can take some time for large point clouds. It outputs in D:\data\potree_converted a directory structure with the top-level file cloud.js and more data in the data subdirectory. This is the POTree format required by VR Sketch.

Usage in VR Sketch

To load the point cloud in VR Sketch, first send a SketchUp model in VR Sketch, and then choose the SketchUp menu extensions -> VR Sketch -> View a point cloud to add the point cloud over this model.

You cannot move, resize or reorient the point cloud. You can move and turn the regular SketchUp model instead; more generally, you can use the full VR Sketch normally to make or edit your SketchUp model. The point cloud is not saved with the SketchUp model; it needs to be re-loaded explicitly the next time if you still want to see it.

You can hide parts of the point cloud using the new tool "point cloud" that appears on the right below the paint bucket. This tool also provides a context menu command (via the "menu" button) that lets you show again all the hidden points.