Project Update:

I'm about a month behind where I thought I'd be by now because of the holidays and having to write a mouse emulator, but I'm back on track now and hit a major milestone tonight. I finally was able to scale up the system and physically walk around SkyRim in my backyard!

I need to qualify that sentence because it sounds a lot better than it actually was. I was confined to a very small 15' x 15' area (maybe double that area in-game) and there were a ton of calibration problems so I had to strictly regulate my walking speed and keep my head still while walking, etc.., but even so - the basic mechanics did actually work properly. I could look around, turn, walk forward and backward, strafe, walk forward with my head turned sideways. Everything was translated into the correct game motions - and for a few brief moments it was sort of surreal.

However the numerous bugs and calibration problems kept it from being very immersive. Here are some major problems that I identified.

1. Numerous calibration and calculation issues. Most of these were already known, but I have been plowing ahead without fixing them because I wanted to get to this milestone quickly. Now I can go back and clean up.

2. I rigged a quick 6-LED light source together and didn't bother to improve the emission FOV so the camera would lose sight of me quite often. One thing that I learned from the experience is how problematic head motion is going to be for the LED camera because it tends to move the light into an edge on orientation. Also looking way up or down occludes the light with your head. I definitely need to create a very diffuse light source.

3. A fundamental problem is the total "disconnect" between your real life walking speed and the character speed. All the subtle speed variations that you tend to make are completely lost and translated into a binary "stop" or "go" speed. That is a major inhibitor to the feeling of immersiveness and is potentially a deal-breaker for the whole idea - at least for generic gaming.

You took a brief step forward in time. That feeling of being in the world is what people of the future will constantly experience.

Branntlew... thats pretty awesome man. KUDOS to you!

Physically walking being transfered into a digital world is pretty sweet stuff. I think Omni Directional Treadmills are the way to go for this type of tech. Once they become more compact ofcoarse.

Sure, probably wouldn't be that hard, but if someone did that, and released it publicly, we might just end up with all 3d devices banned.



Heh, Strange, isn't it

Thanks for the encouragement guys. It helps keep me motivated on a long project like this.

@Moggle69: Omni-devices are cool but I don't think they are very realistic for the average guy. It's bad enough we have to drop over $500 on an HMD, but adding in a piece of equipment that would easily cost over $5K is too much to ask of all but the most die-hard guys. A natural motion tracking system could potentially cost less than $200 and provide a superior experience than any omni-device! So from a pure "value" perspective I think some type of tracked natural motion system (whether Kinect or something like mine) is a clear winner. If you want to experience VR movement anytime soon (outside of CES demos) then this may be the only option.



I've been thinking about problem #3 a bit and I think maybe using the 360 controller interface instead of WASD keys would help a lot. The 360 controller provides continuously variable character speed and direction - true? Unfortunately since GlovePie 0.45 STLL doesn't support Vuzix I'm going to have to implement yet another device emulator if I want to test that. Aaargh! (or get a different HMD )

I hear ya.... my only question is, how do we fix the barrier issue?

Lets say you have an empty 200sqft room. You start in the center of the room, put your HMD on and start playing. What is going to prevent us from walking into the wall?

I thought it was Vuzix that had banned Carl Kenner, but I see in the documentation.rtf for GlovePIE it seems to have been 3Dmtbs.com that banned him?



Is this old or something? Or has he been banned from heaps of places for some reason?

Are you quoting Carl Kenner? Is he banned from MTBS?

I suggest you take a look at this thread: viewtopic.php?f=120&t=13784

As for avoiding hitting the walls, the answer is re-directed walking. You will find some stuff in that thread, I believe.

There's also a good bit of discussion of redirected walking throughout this thread.

@brantlew: Awesome work man! Seems to be coming along nicely. If you need some help getting the Vuzix tracker to work, I may be able to provide some code to get you started. Just PM me.


If he's banned from MTBS, I may be able to reverse that. But from what I understand, he was banned from the Vuzix forums.

Thanks Cyber. I'm using the Vuzix tracker now which is why I'm having the issue with GlovePie. CyberVillain is working on the Sparkfun driver and I have high hopes for that little piece of hardware. However since I only have a Vuzix HMD I will continue to have GlovePie woes (sigh)

Eugh! CarlKenner again?!?

With respect, we aren't bringing him back. We haven't banned someone from this forum in years (with the exception of spambots), and we did it because he was making an active effort to be disruptive and really bring this place down. He has political (and social) views that he felt entitled to express here at MTBS, and that's not the purpose of this site. When we politely asked him to stick to 3D and handle his inflammatory poltics elsewhere - he refused, and further blasted away in the chat window. I wasn't the one who banned him in the end - it was Sharky after Carl went on a personal tirade against him despite all his hard work on MTBS.

There is good cause for CarlKenner not to be here and other sites, and while he has undoubted expertise and passion for 3D and virtual reality, I'm not confident he could contribute to MTBS without bringing back his negativity as well. Thanks for your understanding.

Regards,
Neil

Thanks Neil, I guessed it might be something like that.

It's been a while since I updated. As usual...work, other projects, and procrastination have slowed my progress, but I've been ramping up the last week or so and have some things to report.

I spent a bunch of time in January trying to track down some calculation errors in the computed world position of the light source. I found a couple major bugs fairly quickly that reduced the error a lot, but my calculations were still off maybe 5% at certain angles. I spent some time doing tedious measurements to determine accurate FOV of the Wii camera and characterizing lens distortion. Unfortunately, I never could find the source of the problem so I gave up and moved on. I can live with the errors for now.

Recently I have been preparing for a big data-gathering push. I realized very soon after my first live walking test that my motion tracking algorithms needed a LOT of work. It's one thing to track a light source moved smoothly by your hand. It's another thing entirely to track a light bobbing around and turning on your head. All that shaking around and turning has to be subtracted and smoothed out of the signal in order to come up with a decent character motion model. So I have been modifying the software to do some field recording of sensor data during locomotion. I will use the recorded sensor data to tease out this signal and tweak the motion tracking.

But before that can happen, I need a decent light source. So this last week has been spent trying to build some type of strong omnidirectional light source on my head. Basically I made a three sided pyramid on a pedestal and wired 6 LED's per face. The whole thing is then attached to a pair of headphones. This way the LED's sit right on top of my head and point directly back at the camera. Maybe I should have created a 4-sided pyramid but I only ordered 3 LED modules a few months ago and was working with what I had. Anyway, my hope is that the edges of the pyramids can still be detected. I wanted to encase and diffuse the whole thing in a ping pong ball, but I think it's going to be too big for that. Anybody got any bright ideas of how I can create a diffuser?

So here is a pic of my first prototype. I still need to finish the wiring and soldering but you can see the structural design.



I am eager to do some range testing (it needs to be detectable at about 100ft (30m)) and then get my data gathering underway. Unfortunately I broke one of my LED modules during construction so will have to wait until a replacement part comes in. I'll post of pic of the completed unit and give a performance update pretty soon.

Update: Well after digging around I found this thing that will hopefully work well as a diffuser (and also make me look even dorkier )



http://www.twistncflcovers.com/item/basic-product-line/round-cfl-cover-and-snap-base/lid=16049527

Nice work. Am eager to see where this goes.

I have also made a few efforts to create a diffuse LED light source.

Method #1; Apply transparent "disappearing" cellophane tape. Moderate diffusion, but easy to add more and it seems to be more even than my other method.

Method #2; Grind the top of the LED to change its shape. The next step, I didn't try since I didn't have one, but a friend used a buffer to smooth its shape and make it more transparent. However, the results were not an even spread of light.

Method #3; bend the LED's different directions. However, in your case, since they are pre-made modules, they may not have allowed for enough space between the LED and the circuit board.

Joe Dunfee

@Joe: Luckily I found pre-built modules with "wide" angle (50 degree) LEDs, so they spread pretty well to begin with. Just to be sure I went ahead and clipped the tips of them as I have heard anecdotal evidence that it increases the angle. However, subjectively I really can't tell the difference - plus that's how I broke one of them. Aaargh!

Interesting tip about the tape. Would you use the "satin" looking kind instead of the clear? And you just stick it right on top of each LED? Simple. That worked well for you?

Yes, the satin type. Of course, keep in mind that it would cut the output somewhat.

I just stuck it on top of the LED. Though, I imagine there might be some way to do it more professionally. The tape stuck onto a curved surface does not look that good. Perhaps on the flat snipped-off ones it would do OK.

Joe Dunfee

Maybe you could try a cylinder out of very thin paper or mate foil. Maybe you could wrinkle it in the pyramid base form to preserve trackability.

Exaple of the paper I mean:
http://www.pss-treff.de/bauen/mig3/butterbrotpapier.jpg

In germany we call it "Butterbrotpapier" which translates to "Butter-Bread paper" it is used to wrap up lunches etc. its quite thin as you can see in the picture.

That's a good idea.

An extension to that idea would be to take the thin paper, wrap it around a balloon, use a clear glue to harden it, and then pop the balloon to create a stiff sphere of thin paper. (paper mache I believe it's called) It could have very good diffusion properties, but it would also be fragile.

yeah that is pap mache. The problem is that you only can use one layer of paper, normaly you user several layers of toilet paper.
but its easy to try since that kid of paper is sold in 10m rolls in every supermarket for nearly nothing.

an alternative would be frosted plexiglass:
http://www.estreetplastics.com/Frosted_ ... _s/142.htm
That would certanly give more stability. Also you can bend it with hot air, but you have to be carefull with that xD
I can't say for shure if the frosted status survives the bending, I only worked with clear material.

You can buy frosted window film for pretty cheap, its basically a big decal that fakes the frosted glass look. They have them at my office, they are fairly cheap.

For example:



http://www.purlfrost.com/purlfrost.php

A lot of good suggestions.

I ordered that bulb cover because it's cheap, durable, and requires no construction. But if that doesn't work, I will consider all of these options.

Thought i'd already said this, but can't you get the same effect as frosting by lightly sanding the LED's?

Quick update. Did some quick range testing on the prototype unit with mixed results.

Good news: Light detection during angular rotation of the unit was very stable. Those wide (50 degree) LED's work great, and I saw very little signal loss as I pitch and yaw the unit around. It looks like I won't even need a diffuser. That's a good thing because the diffuser bulb that I ordered really sucked and cut the brightness way too much.

Average news: Those little 6 LED modules are not bright enough to cover the full distance across a basketball court (100 ft). At 25 and 50 ft I get solid signals. Very intermittent at 75, and virtually no signal at 100. That's not too big of a deal however since I can just scale up using the same design. This bad boy should do the trick:




Bad news: My optical resolution (the physical distance I have to move the light to register motion in the camera) seems much worse than I imagined. I'm not sure why. Simple math told me that I should expect an optical resolution of about 1cm/pixel at 50 feet. But my quick field test suggested that it was more like 10cm/pixel !! (I still need to do a more rigorous test to confirm this) That's really bad news because if true, then it means that I cannot use the optical signal alone to detect motion smoothly. Not a total deal-breaker - just means that I will need to augment the signal with an inertial sensor, but I had hoped to keep the design simple by just relying on optical.

I know you've already got it sorted out, but as far as LED diffusers go, I've found that gluing one of these beads to the end of the bulb works quite well.

@brantlew: Cool.

Help. Need mechanical solution for keeping a set of headphones steady. Even without extra weight attached none of the headphones I have tried clamp my head tightly enough, and so they tend to dislodge and shift when I move my head up and down. With the extra weight I am adding to the top, the problem is even worse. So far I haven't figured out a solution. I have considered using a cloth headband and somehow sewing or attaching it to the sides of the headphones so that it will give me a little stability, but I'm not particularly fond of the idea. Maybe some type of plastic ring or helmet - like the liner of a hard-hat. Ideally something simpler though. You guys that work on HMD mounting solutions have probably come across something that would be helpful. Any ideas ?

In-ear headphones?

I'm mounting bulky motion tracking equipment on top of the headphones. I guess I don't have to mount it on headphones - per se, but it is a convenient location. Earphones will work fine, but I still need a stable mounting point on the top of my head. I might also be able to get away with a mount point on the back of my head (maybe counterbalanced with HMD). Any suggestions?

Project Video Update:



I have not talked much lately about this project, but I have been working like crazy on it. There have been a lot of technical problems solved and some significant redesigns in order to get it to the point where I can do field-testing. The video shows at what stage of development I am at. I have an untethered and functional back-top unit now, and the system has been fully scaled. This only shows a basketball court, but I have done field testing on a football field and it scales to that size as well.

The motion detection algorithms are still prototype and need a lot of work. There are some obvious flaws and delays that are clearly visible in the video. But the motion control works well enough now for me to continue developing boundary enforcement and redirected motion (none of which is shown in this video). I am particularly satisfied with how well the independent head/torso motion is working. This game (theHunter) does NOT support independent head motion - just mouse-look and WASD - so all of the walking and looking around that you see is derived from that basic interface.

I am not going to go into too many details about the technology, because I am thinking about turning it into a commercial product. The timeline is difficult for me to estimate because there is still a lot of R&D and some incredibly difficult problems to solve, but I would like to get it to market by the end of the year. Maybe some beta testing to forum members would be available earlier.

In the meantime, I've still got tons of development to go. Also, I bought SkyRim when it first came out, but I have not allowed myself to play it, because I knew it would suck my time away and distract me. My goal is to alpha-test this technology with SkyRim. Perfect timing for my ST1080 to show up as well

That is Rad! How is the level of immersion at this stage? This is close to my ideal VR setup.

Looks great! Can it only track the one set of sensors currently?
The immersion must be way better with the ability to walk around.

@FingerFlinger: Right now the immersion is not good because it's so dangerous! I'm usually testing this outside at nighttime, and without boundary enforcement I am constantly in fear of smashing into goal posts and other obstacles. I've twice come within half a meter of crashing right into a pole. The first time I tried to film this was on a bright and sunny day so I had to use a blinder. I ended up smashing right into my camera and nearly broke it. There are some other frustrating glitches that take me "out of the moment" but all-in-all it's pretty cool. I think once I get boundary enforcement working and the ST1080 and/or the Oculus Rift, I will be be able to relax and really get in to it.

@WiredEarp: If you mean does it currently only track a single point, then yes.
There are some very subtle things that add to the immersion in a big way. Though it doesn't match your head bob in 6D, it does mimic the slight bounces of your head as you walk which is something you don't experience on a stationary system. Also the "quasi"-independent head motion is a real winner. It seems to add to your environmental awareness to be able to turn your head and scan the surroundings as you walk in a straight line. You start to realize how bogus the movement in a FPS is - all those strafe motions and the start/stop/scan habits that you pick up. Independent head motion is more natural and informative.

For a starting point, you could make it just play a tone when approaching a border - that would be way easier than integrating visual cues.

For a game that doesn't support proper independent head motion, it really looked pretty good! I agree about the little head movements adding a lot to immersion.

I'd pay good money for a system like this that could support 12 players locations. I'd only need the location/direction vectors, since I could use devices such as a Hydra in a backpack to provide head/gun/hip tracking.

Getting 12 accurate x,y locations is relatively simple, but getting accurate direction vectors is really freakin' difficult because the yaw sensors are all so "drifty". But you HAVE to have perfect yaw vectors if you want to put players in the same play area. So that's the rub. Players must stay in the same reference frame or else they will start smacking into each other. Compounding the problem is the fact that not only must you have perfect yaw in the real-world, but you must have perfectly aligned yaw in the virtual world as well. In other words - a 90 degree turn in the real world corresponds to exactly a 90 degree turn in the virtual world - otherwise we have frame drift again and bruised players. Mouse emulation is inherently drifty. So without game supported absolute yaw, we're doubly screwed.

Luckily for single player the reference frame can drift all over the place without consequence. In fact, that's the whole point of redirected motion. But open environments and redirected motion are totally incompatible with shared multi-player areas. The best you can do is have a partitioned play field with each player running around in their own little area.

If you have accurate enough yaw you don't need redirected motion for a shared space, you can simply render the other players in the 3D world and let them avoid them in that way. That way, lots of players can share the same area.

I know what you mean about mouse emulation and single player accuracy etc, for any serious VR role mouse emulation will never cut it IMHO, so I only consider it for playing games using VR tech, not for real VR.

Looking good. Nice work.

One thing I noticed, though, is it seems you are moving very far in real life, but only moving slightly in the game. Was this intentional?

Just depends on what the default game walking speed is. Whatever the "W" key does is what I do. So if the game supports configurable speed then you can calibrate it to your walking speed. I'm also sort of "overwalking" it just to make sure the input signals are clear but I could slow down a little to match the game a bit better. Actually this game has a more realistic walking speed than most because it's designed as a simulator (of sorts). I've noticed that the default speed in SkyRim on the other hand is closer to a run.