When uploading a scan, it is important to understand the wide range of file formats that the Prevu3D pipeline supports.
Warning
When it comes to 3D scanning data, there are different kinds of point clouds, and understanding the differences between these types of data is crucial in order to provide Prevu3D with a dataset that can be processed into a 3D mesh model. Before reading this article, make sure you understand the different terminology surrounding scanning and refer to Data collection for more details
What we need to create a Mesh
We need to be able to compute a normal (direction of surface) for each point. See below how we can achieve that based on the type of scanner.
For optimal result, we recommend having the imagery to do the texturing and enable the photosphere navigation mode.
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If you don’t have the imagery, rest assure the quality of the geometry resulting from the meshing won’t be impacted. It’s only the visual look.
Terrestrial Laser Scanning Data
Prevu3D supports the meshing of high resolution terrestrial scanners using the vendor neutral E57 file format.
The E57 file format is a compact, vendor-neutral format for storing point clouds, images, and metadata produced by the laser scanners. The supported E57 is either structured (setup locations included) point cloud with color imagery, or unified (merged) point cloud with color imagery and normal information
With usual terrestrial datasets, we compute normals using the stations position (hence the need for terrestrial datasets to be structured)
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Make sure to look at the Supported Scanners list for more details about the process to get the required & optimal files. If you don’t see your device in the list, please contact us.
SLAM Scanning Data
Prevu3D supports the meshing of SLAM scanners.
With SLAM datasets there are multiple cases:
The pointcloud already contains a normal for each point, so we don’t need to compute any additional information.
Other devices produce both a point cloud and a trajectory. If the format is correct, we can use the trajectory to compute a normal for each point.
Considering there’s no official standard yet in regards of SLAM data, we have a device based upload approach. It will ask you the required files.
Pointcloud (Typically e57 or LAS/LAZ)
Trajectory (if your pointcloud doesn’t contains normal)
Picture (can be embedded inside e57 or external)
Picture position (can be embedded inside e57 or external)
Info
Make sure to look at the Supported Scanners list for more details about the process to get the required & optimal files. If you don’t see your device in the list, please contact us.
Mesh as an Input
Prevu3D supports importing of existing mesh models (from photogrammetry or LiDAR) in the following file formats:
OBJ file format
FBX file format
Structured vs. Unstructured vs. Unified pointcloud
It can be a bit tricky to distinguish the difference between Structured, unstructured and Unified pointcloud terminology. We have an interesting article describing the differences between them.
https://www.prevu3d.com/news/differences-between-structured-unified-and-unstructured-scan-data/