Introduction

The aims of this lesson are to research and explore photogrammetry uses and techniques. Photogrammetry is the process of creating 3D model data from a set of overlapping 2D images (known as a data set). This technique is used in VFX and video games – The 2020 game Microsoft Flight Simulator does this to create a 3D world from 2D geographical map images.

The Process

Photogrammetry is broken up int three phases. The capturing process is where the object is photographed and recorded. The next is the processing phase, where the image data is checked and refined to create a consistent group of images. The final phase is the reconstruction phase, where the 2D images are converted to 3D models using alignment, extraction and reconstruction.

Photogrammetry Case Study

The first task was to research a VFX production that used photogrammetry. The production I researched was the 2021 James Bond film ‘No Time to Die’. In the production of that film, the VFX company FrameStore used photogrammetry to create the main villain Safin’s island base, which James Bond has to infiltrate at the end of the film.

To create the island base, FrameStore first sent a surveying team to the island of Kalsoy in the Faroe Islands with LiDAR technology and drones for initial photogrammetry. Next, they used a helicopter in the air and a boat around the coast to capture an extensive amount of 2D images which were used as data for the photogrammetry.

After adjusting the island’s shape and adding CG buildings, train lines and other man-made infrastructure, the 3D digital island was ready for use in the film’s VFX shots.

Capture – Photography

The main process in the capturing phase of Photogrammetry is photography. Photographs are taken of an object from many different angles and heights to capture every single point of view of the object. In the data set, images which overlap in their view of the object are needed to ensure every point of the object is covered extensively in the extracted 3D model. An actor may be photographed using a spherical rig with cameras around 360 degrees to capture their entire face, so that it can be used in a video game, VFX sequence or similar production

Capture – Video

Another method of capturing an object or environment is to record a video moving around the object. This may not be accurate if the shutter speed of the camera is too low, as a frame of video will be captured less frequently over the same amount of time recorded, resulting in lower framerate. Gimbals will be used with video cameras to stabilise the camera’s movement and create a consistent sequence of image data.

LiDAR

LiDAR, a term that was mentioned in my photogrammetry research, stands for ‘Light Detection and Ranging’ which is where Ultraviolet and Infrared light is used to detect surfaces which are further away and closer to the camera to create a 3D image of an environment or object.

Reconstruction

The reconstruction phase of photogrammetry is where the photos or videos are converted to a 3D model. Photogrammetry software does the majority of this work – the alignment of the images, calculating the 3D depth of the image, reconstructing the images into a 3D model/environment and texturing the model/environment.

Some software that can be used for Photogrammetry:

• Meshroom (free)

• Reality Capture

• Metashape

Model Review

The next task was to download a model created with Photogrammetry and review certain aspects of it according to given criteria. This is the model I downloaded – called Apothecary Vessel for Hop Syrup.

3D Printable Apothecary vessel for hop syrup by Malopolska Museums (myminifactory.com)

This is what the mesh looks like – there are 936,048 polygons in the model.

The topology looks good to me, it seems consistent all the way around. I’m not sure how I would improve the model. It would take me quite a while to model by hand to the same level of detail, probably a few hours’ worth of work – I don’t know anything about sculpting.

Conclusion

Overall, learning about photogrammetry has been interesting – it has an important role in preserving historical artefacts, as well as being able to re-create objects and scenes from real life in 3D for use in entertainment.