This bronze cast is part of Purdue University's Art collection. Two students and I were privileged to go down into the archives and acquire photos to create a 3D artifact of this piece. We used a cross polarized setup to cancel highlights. The workflow: Photo acquisition with a Sony a7rIII and a Sigma 35mm f1.4 lens with a circular polarizer and a Godox Witstro Ring Flash AR400. I custom modeled and 3D printed a housing to fit on the ring light that held a linear polarizing film. A homemade lazy Suzanne and a black cloth backdrop was the setting stage. 285 images were taken and processed through DXO Photolab. The photogrammetry model was created in Agisoft Metashape with an output of a model with 106,676,895 faces. This model was duplicated and decimated down to 2 million faces for export to Zbrush to create a low poly approximate model for real-time viewing. The low poly model was then imported back to Metashape and automatically unwrapped by Metashape. Then a color, normal, ambient occlusion and a displacement map was projected onto the UV unwrap. Using the color map and Photoshop I isolated areas that were metal and not metal and created a metallic map. I also used the same selections from the metallic map, combined with a grey scale color map to create a roughness map. These were then brought into Marmoset Toolbag to create a final turnaround render.
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This is an image of our setup for this scan. I worked with two students helping them to understand the intricacies of scanning reflective objects using a cross polarized ring flash; the lights are shutoff for the actual picture to eliminate any environmental light.
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This scan was made with cross polarization to cancel highlights. The model is a museum quality model from the manufacturer Papo. Several hundred pictures were taken with the model laying on its side and then flipped and merged in Agisoft Metashpe. Zbrush Zremesh was used to make the low poly model, and Maya for the UV layout. Textures were baked from Zbrush.
This radio belonged to a professor friend at Purdue University. It was handed down to him from his grandmother and it is near and dear to his heart. I thought it would be nice to create a digital archive for him to share with the rest of his family.
I was contacted by Purdue's Director and Head Curator of Purdue's Galleries Erika Kvam to see if I could help with digitizing the new Degas Statues that were donated to Purdue. As we had not received the Degas works, I wanted to show a proof of concept that we could do a successful scan of a reflective bronze surface. I used a flash that I modified through 3D printing and linear polarizing film to create a cross polarized rig so as to cancel the reflectance energy. Below is a single rotation done to solidify the efficacy of the technique. The results are promising.
This image shows an example of creating tiled texture sets from photogrammetry scans for a photo real result. Workflow: Panasonic GH6 photo acquisition > DXO Photolab raw processing > Agisoft Metashape > Maya (for simple cylinder and UV layout) > Metashape texture baking > Photoshop tiling textures. You can bake in many different programs such as Substance Painter, but Substance Painter cannot handle the 243 million poly count, so initial bakes of this high of quality are done from Metashape. Textures need to be tiled in Photoshop because Substance Designer does not give the same level of control that hand painted masks in Photoshop do.
Drone photo acquisition is the most economical way to scan items that are very tall. I use a DJI Air 2S with its 1" sensor and 20 mm lens to scan large items like this light house on Lake Schafer, in Monticello, Indiana (my parents are the owners).
Macro photogrammetry is a particular interest of mine. I love doing macro photography, so naturally trying to combine photo scanning and macro photography was a logical direction for me. The challenge of macro photogrammetry is the focal plane is extremely thin. To mitigate the thin focal plane one can do focus stacking, which consists of taking multiple photos at different focal distances. This is a very time consuming process if done individually one set of pictures at a time. However, there are a few cameras on the market that can do focus stacking in camera. I have two cameras with this capability: Olympus EM1 mark III and Olympus TG-6. This scan was done with the small point and shoot TG-6 which has a microscope mode and allows extremely large reproductions of small things.
Below is a small rock donated to Purdue by a local landscaping company. During the pandemic travel was restricted and some of the places one might want to go to get terrain information was out of reach. My goal with this scan was to test the efficacy of using macro photogrammetry to create highly detailed and realistic rock formations from small sources so as negate the need to travel. This scan below has only a single UV set and texture set. With detailed distance based normal map layering in game engine, a small highly detailed rock could act as a convincing large scale land formation. This study led to many more macro tests and research into focus stacked photogrammetry models.