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Starting VR Applications And Using The VR Headset

VR applications are typically started from a terminal window, using the command line. It is also possible to create scripts and/or icons to launch oft-used applications.

Starting a VR application from a terminal

To open a terminal window, click on the monitor-looking icon in the taskbar at the bottom of the screen.

Vrui applications (Vrui is the toolkit / “operating system” powering KeckCAVES's VR applications) can be run in multiple modes, including “desktop mode” and “VR mode.” In desktop mode, the applications behave very similarly to standard desktop (“pancake”) 3D graphics applications. In VR mode, they, well, behave like VR applications. By default, a Vrui-based VR application will start in desktop mode when launched from a terminal window. To launch it in VR mode on the VR headset instead, prepend its full command line with the command “”.

For example, to launch the earthquake viewer application with an earthquake data set in VR, type: ShowEarthModel -norotate -quakes /work/okreylos/PointData/EarthquakeEvents-2016-12-08.csv.gz

When you start a VR application in VR mode, it will by default open a secondary window on the big TV, showing a third-person overview of the virtual environment visible in the VR headset. You can shut down the application later by clicking inside this secondary window and pressing the Escape key. Important: the VR application will not ask for confirmation before shutting down, so please be careful to save all work.

Putting on the VR headset

Important: put on the VR headset front first, not back first. In other words, grab and lift up the strap that goes around the back of the head, and place the headset on your face straight from the front. Only afterwards pull down the headstrap to secure it in place. This is especially important if you wear corrective eyewear: if the headset is put on with the head strap first and then pulling the front down over your face, there's a 99% chance it will get tangled with your glasses, and a 50% chance your glasses will scratch the headset's lenses (which is bad).

Important: do not pull on, or place stress on, the cable connecting the headset to the computer. The connectors at the front of the headset are a little bit loose, and pulling on the cable may break the connection, which will result in a black screen and no VR. Fixing that problem requires re-seating all the cables, shutting down the headset driver, and then restarting it. Ideally, when grabbing the headset's top strap before putting on the headset, place your hand firmly around the cable and the headset's top strap to keep the cable in place.

After putting on the headset, ensure that it is working. You should be seeing the virtual environment of the VR application you started (you might have to look around, including behind you). If it is not working, take the headset off again (for which you reverse the steps of the putting-on procedure, i.e., lift the back head strap first, then move the headset forward and away from your face), and figure out what's wrong. It's probably the cable that has become dislodged.

Dialing in your inter-ocular distance

You should already have measured and memorized your intra-ocular distance (IOD). Before doing anything else, ensure that the headset is configured properly by twisting the IOD knob on the bottom right until the pop-up window shows you your correct IOD, or the closest you can get to it.

Picking up the controllers

The controllers should be lying on the desk somewhere. Usually, they will be tracked by the headset driver in that position, and you will see them inside the virtual environment. If so, you can just grab them. If they don't appear, maybe because they are obstructed by something, you might have to feel around for them. It is good practice to check where the controllers are before putting on the headset, or place them in a position where they can be seen and tracked by the headset driver.

Important Safety Tip

Obviously, you won't be able to see your real environment while wearing the VR headset. So make sure that the space where you will be working is clear of obstructions, furniture, coffee mugs, or chairs.

Very important, and I am not kidding: Never put food or drink items on, or close to, the desk with the big TV. Those items will get knocked over while you are working in VR, and create a terrible mess. It is fine to eat and/or drink in the KeckCAVES lab, as long as food items are restricted to the conference table, and common-sense procedures are followed.

While inside a VR application, the Vrui toolkit will show you a safety barrier when you move too closely to the edges of the configured workspace. The barrier will show up as a green grid, and will become more pronounced the closer you step or reach towards it.

The safety grid is only a rough approximation of the real workspace, and it does not know about moveable furniture items, so make sure there are none. Also, the grid only knows about the positions of the headset and the two controllers, so it can not alert you if you are about to kick the desk, and it does not know what you are doing with your hands if they are not holding one of the controllers (or if the controller fails for some reason).

In short, use the safety grid as a general guide to where you are located in the real workspace, and try to keep it invisible as you work.

Using VR Applications

(this needs an entire set of pages and/or videos)

  • Interacting with VR graphical user interfaces
  • How to enter text or numbers
  • How to bind new functions to buttons
  • How to remove bound functions from buttons (“tool trash can”)
  • How to change the third-person view in the secondary window
  • Per-application functions

Leaving VR Applications

To leave a VR application, it's usually best to put down the controllers first. The safety grid contains two horizontal surfaces; those are areas on the desk that should be kept clear and are meant to place the controllers. Ideally, the two areas will align precisely with the desk's surface and you will be able to simply put down the controllers; in practice, please be a bit careful.

After putting down the controllers, remove the headset in the reverse order you put it on: first, lift the strap that goes around the back of the head all the way off your head, being careful not to pull on the cable (grab the top strap and the cable firmly with one hand). Then, when the head strap is free, pull the headset off your face towards the front. Please do not pull the headset up on your forehead, and especially don't leave it there. Your forehead will end up touching the headset's lenses and smudge them, which is bad.

Next, carefully put down the headset on the desk or on top of the computer next to the desk, with the lenses facing to the front or side. Please do not put down the headset with the lenses facing up (they will collect dust) or with the lenses facing down (they might get scratched). Both of those outcomes are bad.

Finally, close the VR application by pressing the Escape key while the mouse is hovering inside its secondary display window. If there is no secondary display window, move the mouse off the right edge of the screen (where the headset's display is virtually located), click the left mouse button once, and then press Escape. If the application shut down, the terminal window whence you launched it will show another command prompt.

keckcaves/vr_using.txt · Last modified: 2020/03/24 18:03 by okreylos