Building a Context Volume, Final Checks and Documentation

At this point, some additional checks should be conducted by you and other members of the team. These checks are necessary because it is difficult to determine if a volume matches the context it represents when the analyst is only seeing the volume in isolation and/or when the analyst is not familiar with the excavation of the context. Whether these checks happen immediately or at a later time will depend on the whether you are working during the excavation season and the availability of other project members.

1. Bring the new volume into either MeshViewer or MeshLab along with the volumes of surrounding contexts (if they are available). This will help you determine if the volume is in the correct place spatially, and if it overlaps with other volumes.
   1. You can use the Harris matrix for the excavation area to determine which contexts are in proximity to the target context. The matrix can be found in the most recent reports folder for the excavation area you are working on.
   2. Note: overlap between volumes is usually the result of the “double layering” problem (see here) or a missing top point cloud.
2. If you are building volumes during the active excavation season, ask the excavation area supervisor and/or assistant to check that the volume is accurate. If you are building volumes in the off-season, volumes can be checked by other members of project leadership.

If either of these checks identify a problem with the volume, the volume should be marked as “Problematic” in the Master Volume Tracking sheet. The person conducting the check should also add clear notes to indicate why the volume was considered incomplete. The analyst should then continue working to improve the volume. Note: during this process, you should keep all files in the working folder on your desktop rather than deleting/overwriting them, to avoid data loss. Repeat the processing and the final checks above until the volume is determined to be good.

Archiving Files #

Once the volume has been checked and confirmed to be ok, it is time to move all of the necessary files from the working folder to their appropriate archival folders. Below are all the necessary files and their destinations. (Note: if it took multiple attempts to produce a good volume, there will be multiple versions of all of these files; only the final version of the necessary files should be kept.) After all necessary files have been moved, you should delete the working folder and its remaining contents, and empty the Recycle bin to remove any redundant files from the C: drive.

1. [Context number]_top and _base point clouds (.pcd). These are the files that were exported from PCPro and represent the filtered but unclipped point clouds. They will not be kept in the long term and can be deleted.
2. [Context number]_summary file (.txt). This is another automatic export from PCPro that records all the settings used to produce the point clouds above. This file should be moved to gygaia\3Dspatial\processed\[EA]\context_volumes\pcpro_summaries and does not need to be renamed.
3. [Context number]_mesh file (.ply). This is the final volume. It should be moved to gygaia\3Dspatial\processed\[EA]\context_volumes\mesh and renamed so that the file name is only the context number.
   1. Note that if the volume represents multiple contexts, the file name should include all the appropriate context numbers separated by underscores (e.g., “3_4”).
4. [Context number]_top and _base files (.ply). These are the clipped point clouds produced in Cloud Compare; if multiple versions of these files were saved during the volume production process, only the final version should be kept. These should be moved to the “top” and “base” folders in gygaia\3Dspatial\processed\[EA]\ context_volumes and renamed so that the file name is only the context number (e.g., “33”).

Recording in the Database #

After the volume is built and the files are in the correct place, you should note the creation of the volume in the database. Make sure to add the Sample % and between distances used to create the final version of the mesh; these can be found in the PCPro Summary. There is also a space available for processing notes; for example, you might note if you encountered any difficulties, if this volume represents more than one context (or is another special case), etc. You should also note if there are any problems with the volume that could not be resolved (e.g., a bubble that could not be eliminated, if the volume is lower resolution than would be ideal).

Volumes may be reprocessed again in the future, perhaps to correct errors that could not be resolved during the initial processing, or because better software has been made available. Information on how to manage the files for reprocessed volumes can be found here. Any instances of reprocessing should also be recorded in the database, with all the same information that was collected during the initial processing. Note that each instance of processing a volume is distinguished by the date on which it occurred.