If you work in the 3D design space, and especially in automotive rendering, you’ve probably encountered the term "equirectangular panorama."
It’s a mouthful! What does it mean, and how do these unique images work?
An equirectangular panorama is an image that maps a 360° view into a two-dimensional photograph. These images are also sometimes called spherical panoramas, because they essentially map a sphere onto a 2D surface.
How Equirectangular Panoramas Work
We like to think of equirectangular panoramas a bit like a traditional map of the world.
Because the world is round, it’s impossible to draw the Earth's entire surface in one 2D space. Instead, world maps use projections. They flatten out the sphere, turning it into the familiar maps we’re all used to seeing hanging up classrooms and filling geography textbooks.
An equirectangular panorama does something very similar for a three-dimensional scene. It takes a 360° view of the world and uses a projection to map it onto a traditional image file.
In 3D rendering, equirectangular panoramas are used to capture imagery where the viewer is standing in the middle of a scene. These flat images can be loaded into a DCC or other 3D rendering software and reassembled back into the 360° scene from which they were captured.
The Power of Equirectangular Panoramas
Equirectangular panoramas are a powerful technology because they allow high-resolution 360° imagery to be condensed into a smaller, simpler file that can be easily shared and quickly visualized.
Looking at an equirectangular panorama, you don’t get as clear a sense of the scene as you might get looking at a world map. But you can at least get a good sense of what the scene captures.
Long-time 3D designers develop an intuitive ability to visualize these projections that often feels like a 6th sense. They can look at a panorama and immediately see in their mind’s eye what the full 360° scene would look like.
For the rest of us, there are numerous tools for quickly visualizing these scenes in 360 degrees, and all major DCCs support them.
This unique method of projection can also be combined with high dynamic range imagery to create HDRi Maps.
These are equirectangular panoramas with embedded lighting data. Adding this data allows the HDRi Map to capture not only a 360° view of a real space, but also the information needed to replicate the real-world lighting conditions in that space.
Essentially, the technology becomes a way to capture a faithful reproduction of a real-world place. Designers can then insert digital twins of a vehicle or any other object into the scene, add other 3D elements, and create incredibly realistic renders that are often indistinguishable from reality.
How the Images Are Captured
Capturing an equirectangular panorama can be either very simple or very complex.
Consumer-grade 360° cameras now exist and can be purchased for a few hundred dollars.
These cameras use special curved lenses to capture a 360° view of the world, which is saved as an equirectangular panorama with a single button press.
If you’ve browsed Facebook or another consumer-oriented social network and seen a 360° image, it was likely captured on one of these cameras.
These consumer cameras are great if you want to quickly capture a 360° snapshot of a family event or grab a cool travel snapshot. But they don’t meet the quality standards of 3D designers.
To capture the kinds of panoramas that ultimately feed into a professional-quality HDRi Map, photographers don’t capture the scene all at once.
Later, specialized software–as well as skilled human editors–condense all of the data into the final equirectangular panorama.
It’s a much more involved and complex process than using a consumer 360 degree camera, and it’s easy to get it wrong. Stitching errors, lighting issues, the capture of undesired objects, and other problems can easily crop up if the process isn’t done properly.
When it’s done right, though, the end result is an equirectangular panorama with up to 32K resolution, capturing the world in incredible, vibrant detail. Properly created HDRi Maps like those in our collection are so detailed and authentic that they can be used for creating full-motion renders that are indistinguishable from video, as well as all manner of realistic still images.
If you want to create your own equirectangular panoramas for 3-D rendering, you can certainly learn the techniques to do it. If you want to simply experiment with the technology, consider purchasing an inexpensive consumer 360° camera.
Of course, most 3D designers choose to focus on the rendering work they love and leave the creation of these unique images to professionals!
Here at CGI Backgrounds, we’ve spent 20 years building the industry’s best collection of HDR maps and other 360° imagery. You can browse and use our entire collection by creating a free CGI Backgrounds account.
