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How Not To Setup HTC Vive With Cable From Ceiling

May 2, 2016 | vive htc setup ceiling cabling

Some labs just report the successes. I report the failures, too. It helps to be humbled by reality from time to time, even when seeking virtual reality. This is the story of one such humbling.

A Not So Humble Idea Is Born

As soon as I heard about Vive room-scale, I started devising elaborate plans to create the perfect setup. First, after fitting it properly, I would push the play boundaries and figure out how to get it in the center of my space even though my computer was in an another room. Second, since dragging a cable around the floor would obviously be hugely problematic and lead to tripping and all kinds of other issues, I would, with my enormous supposed genius, create a ceiling mounted system that would solve all the problems Valve and HTC had failed to solve.

Looking back, I'm not sure exactly what I thought I would do. I think I imagined some kind of dog leash retraction system, perhaps with a wire running across the room. In my mind, this would work perfectly - no cable dragging around the floor and nothing to trip over. Just total immersion. This should have perhaps been the first warning sign - a grand plan lacking important, specific implementation details.

I thought I would look way cooler than that, whatever that is. I was wrong.

I supposed I had an advantage over most setups - my lab space has a rather unlovely drop ceiling. That means, unlike many people with plaster or drywall ceilings, I would be able to run cables up into the ceiling from the computer in my office, through the ceiling all neatly hidden from view, and then out from the ceiling right in the middle of my lab space.

This would leave the cable to the Vive coming down out of the ceiling, like some special direct line delivering virtual reality mana from heaven. It would make the VR lab a room where you could just walk in, put the headset on, grab the controllers, and be totally immersed. Sure, there would be this cable coming out of the ceiling, but you wouldn't see anything else - no computer, no link box, no multiple cables snaking in. It was beautiful and made so much sense. Until I tried it.

Putting It Together

Shortly after I got my Vive, tired of dragging the link box across the floor and terrified of stepping on it blind and bringing the virtual world to a crashing halt forever, I decided to put my brilliant plan into action. I found the appropriate HDMI and USB cables. I ran to the hardware store minutes before it closed and bought a 25' extension cord and an adapter with multiple outlets. Somehow the retraction system suddenly made itself clear as inordinately complex and probably expensive, so that was dropped for the idea of just having the cable come out of the ceiling and fall to the ground.

Back in the office, with all my goodies arrayed before me, I braved the ceiling tiles to string my cables. For those who are safety conscious, yes, I did wear eye protection and even a dusk mask. We do things right around here. Still, it was a gross job with crumbly ceiling tile and pieces of insulation coming down on my head, getting all over my desk, and generally making a mess of the area.

After working for about half an hour to get it all strung together, I at least had the presence of mind to test it without putting all the ceiling tiles back in their places and finishing off the cords for good looks. I left the link box and everything connected hanging out of the ceiling with the 3-in-1 cable looped through a strut to simulate the final build. I then took the headset in one hand and started walking around the room with it.

The problem with supposed genius is reality.

Problems Develop

A few things quickly became apparent. First, as I had thought, the cable did indeed reach everywhere in my oversized room. However, within a few steps away from where the cable came down from the ceiling, I noticed that the cable would lift off the floor to get back to head height. The further I went towards a wall, the more this became exaggerated, until close to the wall, the cable was making a sort of flat, elongated U.

I was concerned about this because that meant the full weight of the cable would be hanging off the back of my head whenever I was close to a wall, instead of just that portion that went down the floor. Never fear, I told myself, the cable isn't that heavy, so what.

Despite my cavalier attitude, this was annoying and made the Vive straps pinch hair as the weight of the cable shifted around.

I then picked up the controllers and started waving them through the air. One of the great joys of Vive room scale is that the touch controllers track perfectly in space and you soon lose sense that they aren't really your hands. The slight and subtle haptic feedback makes you feel like you are touching things more or less and, since there is nothing else for the controllers to hit if you stay away from physical walls and ceiling, this slight haptic feedback is really convincing and freeing. That is, until the controllers hit something that isn't in the virtual space, like, say, a cable hanging in the air from your head.

This was true both of the cable when it was off the floor when you were close to a wall, and, even more annoyingly, when you were in close proximity to the cable coming down from the ceiling, which, at least in my test build, was fairly close to the center of the play area. And every time you moved around the cable hanging down, it would start to twist and entangle itself and you.

After one particularly vigorous repulsion of the marauders in the Lab Longbow demo, the archer became entangled in a bunch of "invisible cords". Thankfully, the demo contains only one level, because the next level was going to involve ceiling tiles falling, cables snapping out of link boxes, and myriad other disasters in increasingly annoying reality if I hadn't been able to stop and unwind.

Species: Ceiling Python

I also realized, while looking at the cable coming down from one diagonal of the room, that there was a chance it would occasionaly eclipse one or the other base stations, possibly causing additional tracking issues on top of all its other issues. There are lots of sensors on the controllers and the headsets, so I doubt this is a serious issue, but in general it seems best to keep the tracking area as clear as possibly of anything that might block the base station signals.

Disaster Zone

So it was, at the end of the day, that I spent another hour removing everything, vacuuming, and tidying up to get back to where I had started. Where I had been convinced that the ceiling-mounted cable solution would work perfectly just hours before, I was now quite assuredly of the opinion that it was a terrible solution.

Detritus everywhere. Fortunately at Rainfold, unlike Aperture, the robots are under control of the humans. [s-s-s-so he thinks]

Therefore, I file this report as a cautionary tale to others who may be considering elaborate ceiling setups. I do note that I did not fully explore the idea of retraction, but I'm now sure it would not work because the retraction system itself would pull against your head. Even if you got the tension just right, as soon you turned back to face wherever it came out of the ceiling, it would wrap around your face.

Further, we use our hands in room-scale VR way more than we use our feet, so everywhere the user can move their arms and hands around their body needs to be completely free of obstructions. Even though the cable comes down from the headset in normal floor usage, it is so close to the body this doesn't present an issue anywhere close to the issues presented by the cable coming down from above or the side.

Just don't do it.

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