Since it is a growing field the guidelines and best practices vary. It depends on what technology is being used, and what the institution is digitizing. Here are what some digital libraries, museums, and other institutions say about their practices.
3D Scanning When scanning a turntable for multiple angles is highly recommended. "Lighting and camera angle of view are essential considerations and details of specific regions may be useful." (H., 2013) Several 300 dpi resolution photos are taken of the image using an SLR camera or a scanner designed specifically for 3D is used like GoScan3D! hardware. Files of the images are usually saved as RAW format and converted to TIFF at a later date. "RAW files save the image exactly the way the camera’s sensor “sees” it, and allows color and white balance to easily be adjusted later." (CARLI)
If you use a series of photos an editing program like Photoshop will be necessary to piece the data together. If you have used something like GoScan3D! the files can be pieced together using VX Elements or Geomagic Design X. Once the data is pieced together it is ready to be cleaned. There are usually multiple holes in scans which can be cleaned up using programs like Zbrush. Maya is then used to unwrap the materials and Photoshop is used to fix any texture issues. The completed model is then ready for upload. Photo from: Carli digital collections
Metadata If using Sketchfab most metadata is simple tags like (#anthropology). An archivist will then link the Sketchfab to another collection with more information about the descriptive and administrative metadata aspects. The Sketchfab data is generally mapped to Dublin Core (Mi, 2017) 3D model collections rely heavily on linked data.
If solely using ContentDM a lot of institutions use Qualified Dublin Core and "with regard to 3-D objects, an additional consideration is whether the object is digitized as a single still image, a series of still images providing multiple views, or a moving image." (CARLI) They create compound object and page level metadata to give a general and more descriptive version. |
Photo from: 3dsystems.com
Uploading to Collection Sketchfab is the go to source for most 3D model uploads. Libraries will upload the 3D object to Sketchfab in order to allow users better access to the object. Sketchfab has many different controls like rotation and scaling as well as download functions. Both large institutions like the Smithsonian and smaller institutions like college libraries use it.
The secondary choice is ContentDM. "Libraries can create a unified way for users to view different parts of a three-dimensional object within CONTENTdm by using one of the software’s “Compound Object” structures" (CARLI) The third choice is to create a video or web presentation of the object and then uploading it to your content collection. Photo from: OCLC
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