Following last week's Steam Dev Days conference in Seattle -- a game developer only event where the press wasn't invited -- we're still waiting on promised videos of all of the notable presentations, but a couple of Valve devs have published the slides and notes of their own talks, specifically the ones pertaining to the studio's research and development in the area of virtual reality hardware and software.

Valve's Mike Abrash -- the programming veteran highly regarded for his work on the Windows NT platform at Microsoft and the iconic Quake at id Software -- has updated his blog with links to both his own presentation and that of fellow Valve VR champion Joe Ludwig. Although targeted at a game developer audience, both are hugely informative reports that explain key elements and Valve's findings of VR hardware and software development, and serve as somewhat of a VR-101 overview of the current state of virtual reality tech -- a highly recommended read for anyone interested in the topic.

Abrash goes as far to suggest that the experiences that could be offered with VR tech in the not-too-distant future have the potential to elevate computer entertainment to the top of the entertainment industry:

Once hardware that supports presence ships, we think it has the potential to cause a sea change in the entertainment industry. Not only could VR rapidly evolve into a major platform, but it could actually tip the balance of the entire industry from traditional media toward computer entertainment. You see, for latency and bandwidth reasons, presence can only happen with a head-mounted display connected to a device capable of heavy-duty 3D rendering, so there’s no way that TV, movies, streaming, or anything that lacks lots of local compute power is up to the task. A corollary is that the PC – Linux, Windows, and OSX – is going to be the best place for VR, because that’s where the most FLOPs are.

The bulk of the talk is spent describing that concept of "presence" as the culmination of several crucial factors required to create a worthy VR experience:

This feeling of being someplace real when you’re in VR is well known to researchers, and is referred to as “presence,” and it’s presence that most distinguishes VR from 3D on a screen. Presence is distinct from immersion, which merely means that you feel surrounded by the image of the virtual world; presence means that you feel like you’re in the virtual world.

Trying to describe presence is bound to come up short – you can only really understand it by experiencing it – but I’ll give it a shot. Presence is when, even though you know you’re in a demo room and there’s nothing really there, you can’t help reaching out to try to touch a cube; when you automatically duck your head to avoid a pipe dangling from the ceiling; when you feel uneasy because there’s a huge block hanging over you; when you’re unwilling to step off a ledge. It’s taking off the head-mounted display and being disoriented to find the real world there. It’s more than just looking at someplace interesting; it’s flipping the switch that makes you believe, deep in your lizard brain, that you are someplace interesting. Presence is one of the most powerful experiences you can have outside reality, precisely because it operates by engaging you along many of the same channels as reality. For many people, presence is simply magic.

All of the following are needed:

• A wide field of view
  
• Adequate resolution
  
• Low pixel persistence
  
• A high enough refresh rate
  
• Global display
  
• Optics
  
• Optical calibration
  
• Rock-solid tracking
  
• Low latency

These elements also reduce motion sickness. While the causes of motion sickness are not well understood, there are good reasons to anticipate that many of the same factors that affect presence should affect motion sickness as well. For example, flawed tracking causes a mismatch between what your eyes see and what your vestibular system reports, and those sorts of conflicts are thought to be key to motion sickness.

Abrash notes that Valve has "no current plans to ship VR hardware ourselves, but that could change in the future", indicating the studio's current intentions are more about driving the whole field forward with a view to making sure that Steam will be a key part of the brave new VR world, and forecasting that "a great VR system at a consumer price in 2015 is more than just possible – it’s sitting there waiting to happen".

There's much more detail on the topic to be found over at Mike Abrash's blog.