Looking From All Angles: ArtLens Exhibition Embraces Photogrammetry

ArtLens Exhibition is an experiential gallery that uses innovative technology to put the visitor into conversation with masterpieces of art, encouraging engagement on a personal, emotional level. The new installation of ArtLens Exhibition utilizes a process called photogrammetry to create sophisticated 3-D models of artwork that visitors can interact with. In the essay below, learn more about this process from two of the principal CMA staff members involved in the project: Maddie Armitage, Digital Project Manager, and Howard Agriesti, Chief Photographer.

What was the goal of this new iteration of ArtLens Exhibition?

MA: The CMA’s cross-collaborative Digital Innovation team is always eager to experiment with new ideas to provide visitors with the tools to look closer at art. On June 14, 2019, the museum’s iterative, rotating gallery ArtLens Exhibition reopened with 21 new artworks from across the museum’s permanent collection. An exciting new feature is the addition of a 3-D viewer in the gesture-based games, allowing visitors to zoom and manipulate 3-D–projected models to see all angles of an object. Visitors can explore artworks in the collection like never before — digitally turning them around to see the tops, bottoms, and insides. These 3-D models were created using a technique called photogrammetry.

ArtLens Exhibition’s gesture-sensing interactives include an “attract loop” menu of artworks installed in the gallery from which visitors can select an artwork to explore. The previous iteration of ArtLens Exhibition used 360 photography for the attract loops. This latest installation represents the next level of innovation. To incorporate these 3-D models into the interactives and our Collection Online, we needed to implement photogrammetry. The creation of these sophisticated 3-D models is an example of how ArtLens Exhibition continues to advance innovation, thus allowing visitors to look closer and dive deeper into the collection.

What Is Photogrammetry?

HA: Photogrammetry can be understood as a way to visually represent real-world objects in a manner that combines photographic imaging with the metrics of scale. The CMA’s Digital Innovation team led the implementation of photogrammetry to create 3-D models of objects. This is not a simple task; it represents true innovation in the museum field. This installation features numerous objects that were challenging to capture using photogrammetry due to their reflective materiality and intricate details. However, we embraced the opportunity, and the museum is now recognized and respected in the photogrammetry community.

In the fall of 2015, I was introduced to photogrammetry by my colleagues Charles Walbridge and Dan Dennehy from the Minneapolis Institute of Art, and I attended a training program they recommended the following year. The photogrammetry method we used was developed by senior photogrammetry experts at the US Bureau of Land Management. It optimizes the data sets utilized and incorporates individually calibrated scale bars that are accurate to 1/10th mm or better. Hence, the resultant 3-D models produced with this method are accurate to that level and have the visual appearance of the actual objects. This method contrasts with laser scanning, which can produce accurate 3-D models, because the resulting objects have a blank surface appearance.

To create a 3-D model using photogrammetry, a series of overlapping photographs are taken of an object, showing every part of the object several times. Those images are then fed into a 3-D software program, which, after a series of processing steps, produces the 3-D model. To complete this work, we used Agisoft Metashape Pro, formerly Agisoft PhotoScan Pro. While some objects were photographed in the galleries or conservation labs, most were brought into the CMA’s photo studio and photographed on turntable setups that were custom configured for each object to optimize results. We used a Crayfish 60 turntable from Seabass 360, a small firm in London, England. This well-built turntable has an excellent control interface, which supports up to 286 pounds. It also features an overhead rotator configuration for hanging certain objects, allowing them to rotate for the camera. For larger objects, we used a heavier manual turntable built by the museum’s exhibition production staff.

Objects such as the fifth-century Greek black figure amphora were photographed using polarized light to eliminate reflections (which confuse the software) and against a black background to further dampen reflections from the surrounding set.

How were the artworks chosen?

MA: The objects in ArtLens Exhibition are masterworks from across the collection and represent the best examples of the gallery’s overarching themes: symbols, purpose, composition, and gesture and emotion. The artworks installed in the most recent iteration were selected by the collaborative, cross-departmental ArtLens Exhibition team, consisting of representatives from digital/technology, interpretation, design, exhibitions, curatorial, collections, and the library. With an initial list of more than 100 artworks, the team worked collaboratively to narrow the selection to 21 objects, 15 of which were 3-D.

HA: These 3-D objects ranged from large to small, simple to complex. On the small side were a pair of ornate 17th-century Nepalese earrings and a tiny bronze Etruscan Dancing Satyr from the 5th century. On the large side was the heavy cast bronze Mother and Child by Jacques Lipchitz and a marble sculpture of early Native Americans locked in combat by Edmonia Lewis. We then had two challenging objects to capture: a table and tea set and a hand mirror. The highly ornate Table and Tea Service by Carlo Bugatti includes seven pieces. The tea set is made of gilt silver with a highly mirrored surface, which is notoriously difficult to capture using photogrammetry or laser scanning. For this object, we collaborated with Dale Utt, a photogrammetry specialist from Minnesota who specializes in photogrammetry of medieval armor. The 3-D interactive community agrees that our early 20th-century hand mirror is one of the most complicated models created due to its reflective surface, ornate detail, and variety of materials.

How can you explore these models in ArtLens exhibition?

MA: Our 3-D models are hosted on Sketchfab, a 3-D creation tool and publishing platform compatible across every browser. Previously, artworks in the attract loop were meticulously photographed and stitched together one by one. When introducing the Sketchfab models, we were able to use the application programming interface to generate these 360s. We decided to integrate the Sketchfab platform into our existing interactives based on the sophistication of the interface and the level of control for modifying and improving the models. When the timed 3-D viewer experience is complete, the object’s next game begins seamlessly. CMA’s contracted developer, Alex Lew, played an instrumental role in creating these 360s and integrating the Sketchfab models into the existing interactives.

Our team partnered with Potion Design, who led the UX/UI development for incorporating the 3-D viewer into our existing gesture-sensing interactives, while we provided feedback and conducted user testing. We spent a significant amount of time fine-tuning the visitor experience so that users could interact with the 3-D models in a rewarding way.

Since ArtLens Exhibition reopened, we have witnessed visitors of all ages interacting with our new 3-D models, and we will continue to add more. In addition to photogrammetry, we also added the ability to scan 3-D artworks with ArtLens App and a new video on the digital Beacon that features more visitor-generated content. Finally, look for links to our 3-D models on our Collection Online later this summer.

This blog is the third in a series highlighting the new installation of ArtLens Exhibition. Read part one by Jane Alexander here and part two by Jenn DePrizio and Jim Engelmann here. For our final blog post in this series, Hannah Ridenour, research manager, reviews the ARTLENS Gallery NEA study and tool kit.