Why full-body VR is hard

May 27, 2022

Spatial are a company that started out building virtual meeting rooms (or collaborative spaces), and have pivoted over the last couple of years towards a Metaverse strategy of World Building and Web3. As part of this strategy they decided to ditch their avatar system in favour of a new full-body version provided by the fantastic Ready Player Me.

Ready Player Me Avatars

Now, it is worth pointing out that RPM already offer a decent half-body avatar solution for use in Virtual Reality so the decision to go all-in on the full-body wasn't out of necessity. So why did they choose to do this, and what are the pros and cons?


The RPM avatars are very cool and allow for customisation that includes a ton of fashion accessories and cultural accoutrements. You'd really be missing out if you weren't able to customise the legs and feet ... especially if you were a footwear brand! Users want to jump, dance and pose, be expressive, and whilst that is certainly achievable through gesture and facial expression, it is not the full range.


Games developers have had many years to perfect character animation and locomotion, and the game engines use incredible technologies to blend animations and create believable and reactive movement. Advances in AI has also enabled characters to intelligently adapt to their surroundings and situation; to bounce off walls, interact with other characters etc. This technology will be critical if we want to emulate a users pose, gestures and emotion in real-time. VR users are more likely to incorporate teleportation and soft-rotation as well so the engine will need to represent these changes within the space in a way that is natural. Users in Meta's Horizons have been complaining about other users using teleportation and urging them to disable the feature in favour of smooth motion. It seems this is an emerging etiquette issue that will need to be resolved without compromising the issues around motion sickness.


We are not all designed equally, but although our avatars are diverse, their heights are not. VR users are usually depicted in spaces at their actual height, something very apparent when in a space with people who are sitting. I'm not completely sure how Spatial are dealing with this issue other than forcing everyone to appear to be standing and at an equal height. Would love to hear if they are planning on tackling this issue and how they intend to reduce the heights of the RPM avatars without just scaling everything down.

I have experimented with using RPM full-body avatars in Unity myself and creating an IK system for the avatars that adjusts the legs based on the headset height in the real-world is very difficult. If you are short (like I am) you end up with an avatar who is constantly bent at the knees, shuffling along the floor like a crazed drunk. It's not pretty.


This is a very interesting time for technology companies in this field, and it proves that avatar design is not so straightforward. Customisation will have to support body types and heights with the ability to adapt on-the-fly based on whoever is wearing the headset. The challenge is doing this whilst still allowing for creativity and expression.

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