【转帖】creating program to link head tracker for desktop vr

yang686526

creating program to link head tracker for desktop vr
sorry if you've already seen this message, somehow my messages have been appearing in the wrong forums. the window i am typing this into has "category: api" at the top, so hopefully it is right this time.
i have been looking into this subject, off and on, for probably a decade. i have always sat back and assumed that it would eventually be available for low cost or free. i keep seeing university projects where someone does a demo to prove that it works. but it seems like it never gets to the point of being useful because the "proof of concept" software is not a cad design tool.
i've done a little bit of machine coding 20+ years ago, and more recently a substantial project for autocad using vba. but, i am not familiar enough with the world of programming windows and sw to know what would be involved in getting one of the view-point trackers based on a usb camera to talk to sw.
so, if i decide to take this on myself, what would i need to learn? is this something that can be done in visual basic?
joe dunfee
sw 2009 sp3.0 windows xp
hp compaq dc5800 microtower
nvidia quadro fx 3700
hey joe,
although i have never looked in that direction of the api, it does not seem "impossible". i do believe that visual basic would be able to handle this. vb.net express is available as a free download from microsoft (incase you don't have or didn't know this). just a quick search of the api help lead me to modelview.translateby ( x, y ) and modelview.zoombyfactor ( factor ).
obviously, a lower brightness would mean that you are farther away from the webcam while a higher brightness would mean you are closer. i am sure that you would need to take this into consideration when coding the "zoom" portion. as long as you can extract the coordinates and monitor the brightness, i don't think this sounds too far fetched - they can do it with a spaceball. i probably did not shed much light on the question, but i hope this helps a little bit. if you have the time, check out sourceforge.com - you may be able to pick some things up from there.
tony szuta
cswa, cswp, cswp-smtl
actually, the brightness is not necessarily the method for determining distance. in the wii, the angular distance between two dots a known distance apart from each other is the method. of course there are trade-offs with this method. if you turn your head, it would produce false distance readings, but if you are looking at your screen then it can be assumed that the dots are square with the display.
i've also seen methods that used two web cams to allow full 3-d triangulation. but, i don't think full 3-d tracking is necessary if you are just doing desktop vr (also called "fish tank vr). in desktop vr you can assume the viewer will stay a fixed distance from the monitor. and if the registration is a bit loose or lagging, it won't have the nausea-inducing effects of true immersive vr. in fact, a little wobble in the image fits with the title of "fish tank vr"!
while visual basic, like any high-level interpreted language, is probably a poor choice for something like this... it is free and what i am familiar with!. all that really needs to be done is to accept the api feed from the head tracker and port it over to the api of solidworks.
joe dunfee
sw 2009 sp3.0 windows xp
hp compaq dc5800 microtower
nvidia quadro fx 3700
if anyone wants more information about the wii remote. here is a very informative wiki,
if i reply too many times to myself, it will start to look like a blog. but, i know there are others here interested in this, so i will keep you all updated on my efforts and discoveries. i found this guy who has a demo working with a web cam using the microsoft .net platform.
hi this sounds very cool. i have done quite a bit of vb programming developing plugins and i also have done quite a lot of electronics. in my opinion the amount of effort from the sw api point of view is quite minimal and you could achieve it with not too much effort. essentially you are going to want to use the functions for rotating and zooming and panning the view. get yourself a copy of visual studio (express) and install the solidworks api. create a new vb plugin using the swaddin template. compile and then start solidworks - excellent start point as the code is working. then use the solidworks macro recorder to get some code for zooming, panning and rotating the view. play around cutting and pasting code and you should get the idea.
i suggest in addition to accelerometers you also look at magnetomers which measure magnetic field you can then use the earths magnetic field to determine your head direction just look at the screen and have a simple calibration routine to let the computer know that that is zero degrees. just don't sit near big speakers
ps your links aren't working.
cheers
tom
regards
tom mulder.
compac nw8440
intel core 2 t7400 2.16ghz
ati mobility firegl v5200
solidworks 2008 sp4.0
windows xp professional sp2
another sofware solution, the freetrack is a program that uses a web cam to track up to 4 light sources, and if you use at least 3, it will generate 3-d viewpoint information. it has configurations for a lot of games, but no cad.
it seems to be a well done piece of software, with a lot of adjustments and configurations available. i just started trying it out with solidworks by setting it into mouse mode and with a single red led in 2d tracking mode. then, i hold the mouse button down as though i wanted to rotate the view. as my led moves around, the object rotates... actually it rotates wildly.
but, i will start to work on the 3d led version, so i can get true viewpoint tracking, and then tackle attempting to interface it with solidworks. i don't think the mouse emulation mode is going to be useful. if anyone has insight about how sw may interface with other head tracking software, that may be useful information. it would make life very easy if it happened to be compatible with some other profile that the treetrack software already knows about!
joe dunfee
sw 2009 sp3.0 windows xp
hp compaq dc5800 microtower
nvidia quadro fx 3700
quick