Four Ways to Share Space in XR
February 21, 2024
There are several ways to approach designing shared spaces in XR, from wormholes to digital twins. ShapesXR can help you find the one that works best for you.
A shared space is a place where people can see and hear the same thing in the same position. They can point or look at an object and both know what they are looking at. But how do we set up this shared space? There are four main ways to create shared spaces between remote users:
- Virtual space with locomotion
- Content as the anchor
- Wormholes and portals to connect physical objects
- Digital twins with remote locomotion
1. Virtual space with locomotion
Virtual reality has always promised to transport us to other worlds and spaces. But no matter how immersive the virtual world is, the user still has to consider the physical space around them. If they walk far enough in the virtual space, they are going to eventually hit a real wall. If they want to move further they need to teleport to remap their physical space to the virtual space. Teleportation works well but gets more complex as you bring another person into the equation.
To share space with others, most immersive VR apps allow each user to move freely around the virtual space using teleportation or movement on the control stick. Think VR Chat, Rec Room, Horizon. There is nearly infinite virtual space, and the users can move around it with as much physical space as they have available. In ShapesXR we decided to teleport and directly manipulate the world to move around the virtual space.
Dig deeper in this asynchronous lecture.
If you want to experience this space first hand, open the space in ShapesXR on a Meta Quest.
Locomotion around a shared virtual space works well in immersive worlds, but things change if the users can see the real world.
2. Content as the anchor
When we try to share space in the real world things get more complicated. On augmented reality displays like Hololens or Magic Leap the real world is the primary reality, and you can’t easily replace it with a virtual world. So how can you have shared multi-user experiences with both remote and co-located users? Apple, Microsoft, Magic Leap, Unity and Meta have all solved this problem by aligning everyone around a shared piece of content. Here you can see people surrounding a shared game board. Moving that board to another physical table brings all the remote users to that table as well.
Apple’s shared space platform has a few templates to foster different types of social interactions.
Each of these layout have different social dynamics. Side-by-side is good for content that should be seen from the same angle, like a TV show. Surround is good for tabletop games. Conversational is good for presentations. Learn more about them in Apple’s video on shared spaces. And here is a another async lecture on the subject.
Once again, you can a feel for them first hand in this ShapesXR space that shows all of these templates. We recommend jumping into this space with a few other people and positioning yourselves in these orientations to get an understanding of what works in which situation.
3. Wormholes and portals to connect physical objects
The most mind-bending type of shared space are wormholes, where two physical objects are connected in different locations.
A good example was the original version of the app called "Spatial". Spatial asked you to find and mark the largest vertical surface in your room. This surface became the main anchor for the shared space and allowed everyone to have a shared wormhole between their walls. If I placed a sticky note on my wall, I knew that it would also be placed on your wall. This works for as many people as you need.
The game “Cybrix” does the same for their mixed reality mode but uses a portal to connect rooms together, but each of your are inside each other's walls. You see the other person inside the portal. This works well to connect two rooms, but not three.
Horizon Workrooms uses desks as wormholes. You first mark your desk, then it maps the desk to one of the virtual world’s desks. When you teleport around the room you are actually teleporting your physical desk to the virtual desks in the space. Once the wormholes are set up, it allows the virtual space to adapt in ways that are impossible in the physical world.
When more people join the meeting room can scale accommodate more people, but your desk stays mapped correctly in the virtual space.
Horizon Workrooms has yet another type of wormhole: the whiteboard wormhole.
When you initially set up your space, it asks you to find an open space in your physical space where you have enough room to whiteboard. Then when you stand up from your desk and move into that space you are automatically teleported into the whiteboard space in the virtual space. By physically moving between your wormholes, you are teleporting two different positions in the virtual space. Mind-bending!
4. Digital twins with remote locomotion
The final frontier of shared space is having shared physical spaces where remote users can join, see, and interact with the remote representation of the physical space and the people in it. Imagine a digital twin of a museum. Remote users can visit the museum in VR, but people in the real museum can also see and interact with the remote visitors. Imagine an art docent wearing AR glasses and guiding a combination of co-located and remote visitors through the museum. This isn’t science fiction anymore. Meta’s shared spatial anchors and room meshing features on the Quest 3 make it possible today.
Here’s an example in ShapesXR where one user has scanned their home and the other user can join remotely. One user moves physically in their room seeing the real world. While the remote user teleports through the space while seeing a 3D scan of the room. The entire room becomes the shared anchor for the space, enabling a collaborative shared experience where they can hide behind couches, dodge incoming fire, etc. And the remote user doesn’t need to be restricted by physical constraints. They can be tiny or giant, go inside physical objects or outside windows. The possibilities are endless. To set up a digital twin you can follow along with this video
Open this space inside ShapesXR to experience the tutorial first hand.
When to use each type of shared space
- Virtual space with locomotion:
If you want to completely immerse users, use teleportation to allow users to freely move around the shared virtual space. The users won’t have the same view of the same content, but they will be able to use proxemics and spatial awareness as they move around the virtual world. - Content as the anchor:
If you are sharing a single piece of content, use the content itself as the anchor that connects users. You can automatically place users side-by-side, in a circle around the content, or in a half-circle next to the content. - Wormholes and portals to connect physical objects:
If users are orienting themselves to a physical object or surface, consider using it as an anchor in the shared space. Tables, chairs, keyboards, or walls are all good examples. Users can be on the same side of the anchor, rotated, or mirrored to merge realities in new ways.
- Digital twins with remote locomotion:
If one or more collaborators are using an entire physical room to collaborate, consider using the room as the anchor in the shared space. This will require a 3D scan of the room that remote users would see as they move about the space
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