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Better understand E57 files

⚠️ Please note that for better performance of the Viewer, it is recommended to have a structured e57 with all the stations inside rather than a structured e57 for each station. ⚠️

 

Structured Scans

  • The structured data contains each scan location, each panoramic image  (NOTE THAT THIS DEPENDS IF THERE IS A PANORAMIC IMAGE STORED IN THE E57) depth map, and the 3D point cloud, as the result from the registration process.
  • Each scan location is visible in the 3D space.
  • It’s possible to be in each scan position, see the panoramic image (IF THERE IS NO PANORAMIC IMAGE, YOU WILL HOWEVER HAVE THE 360 VIEW BY DISPLAYING THE STATION'S POINT CLOUD) and navigate from scan to scan.
  • File size for each scan is big, especially if there are panoramic images too.

Unified (unstructured) Scans

  • Unified scans lose the ‘structure’ of the project.
  • Scan positions are no more visible in the 3D view.
  • Panoramic images are lost (if there were any).
  • Navigation from scan to scan is no longer possible.
  • The quality of the scan project is affected.
  • Overall file size is slightly smaller, making the 3D point cloud somehow easier to consume in desktop modeling apps such as Autodesk Revit for example.

 

 

Unstructured point clouds are generated from:

  • Mobile Lidars
  • Drone-based photogrammetry
  • This data is ‘unstructured’ since there are no scan positions associated to a depth map as produced with laser scanners on a tripod.
  • It’s pretty similar to a ‘unified’ point cloud.

 

Structured scan file formats

  • (Structured) RCP: the native format for Autodesk ReCap projects (upload it as a Zip file)
  • (Structured) E57: the standard exchange format for terrestrial laser scanning
  • Every point cloud software provides the option to export a structured E57 file.
  • Faro Scene, Trimble RealWorks, Leica Cyclone, Topcon ScanMaster... (NOTE THAT NOT ALL SOFTWARE EXPORT E57 WITH PANORAMIC IMAGES)
  • There are other structured scan formats generated by point cloud software: FLS, PTX, TZF but not compatible for the cloud

 

Structured-to-unified is possible.

  • Every point cloud software provides the option to generate a unified point cloud.
  • Turning a structured point cloud into a unified point cloud is a destructive operation though since the structure of the scan data is lost and the overall quality is affected.
  • Typically, 2 formats are used:
  • Unified RCS, making your scan data directly consumable by all Autodesk desktop apps.
  • Unified E57

 

Unified-to-structured is impossible.

  • Once the scan data has been unified, all the ‘structure’ data of the project is lost, making it impossible to recover it.