How to setup Sensics xSight HMD displays in Vizard

[Zhi]

Hi All,

I am new to Vizard. I just switch from Virtools.

Our lab has a Sensics xSight HMD, with 12 screens (3 x 2 for each eye). Thus, we need 12 windows (or viewpoints) to control the HMD, I think. That is what we did when using Virtools. However, as shown in the Vizard help file (http://www.worldviz.com/vizhelp/Sensics.htm), it seems the only thing we need to do is:

import sensics
sensics.xSight_6123()

there is no more information beyond that. The help file also suggests that the model (i.e. xSight 6123) do not require panelalign.txt or layout.txt files.

I wonder how could this work, since all the individual screens have different pitch, yaw, raw parameters, and their images would overlap each other.

Does anyone has experience on how to configure Sensics HMD displays in Vizard.

Thanks a lot.
Zhi

[Zhi]

I got help from the Sensics support team. Although we have a xSight HMD, we only have a SVC (not SVP) with it. So, we have to use the old script (similar like that used for piSight HMD) as below:

import viz
viz.go(viz.FULLSCREEN)
import sensics
hmd = sensics.load(panelalign='C:\\ProgramFiles\\Sensics \\config\\0118\\panelalign.txt',layout='C:\\Progra m Files\\Sensics\\config\\0118\\layout.txt',clearcol or=viz.BLACK)

This works really well with the master machine. However, the Vizard can not find the slave machine which is specified in the "layout.txt" file.

Does anyone know how to use Vizard to control two computers with different views on the same VR world.

Thanks
Zhi

[Jeff]

Can you explain how your system is setup there in more detail? The number of computers you have and the version of Vizard you have installed on them.

You'll need to have the Vizard Enterprise version to run a cluster (http://www.worldviz.com/vizhelp/What_is_a_cluster_.htm) application. If you want to do some tests and you don't have the Enterprise version for Vizard 3 try out the Vizard 4 Beta (http://forum.worldviz.com/showthread.php?t=3411). That provides an unrestricted Enterprise license with an expiration date.

[Zhi]

The cluster control problem is solved. I was using the Vizard 4 Beta to test our system. I did not realize that I need to use the Vizard tool programs (i.e. the Cluster-master in the master machine, and the cluster-client in the slave machine). After I connect the two machines using these tools, I can run my script from the master machine, and it controls both machine's desktop screens. That's very cool.

However, there was one more issue came up. When the VR scene was updating (i.e. when I rotate my head), there was obvious lines move from top to bottom along the screens. It seems that the vertical blank of the displays were not synchronized with the update of the image buffers. I went to the NVIDIA control panel and set the flag of the "vertical sync" to "force on" (in the "manage 3D settings"), but it did not help. I also added "viz.vsync(viz.ON)" in my script, it did not help either. Do you have any suggestion on how to resolve this issue? Thank you.

[Jeff]

If you hit F4 you should see the framerate displayed. What is the number there?

Does the same thing occur when displayed to a monitor rather than the HMD?

What kind of graphics card do you have?

Does this happen if just load a simple model for the scene:
gallery = viz.addChild('gallery.ive')

[Zhi]

When I press F4, the RF is 59.xx which is about right.

The master machine has two NVIDIA GeForce GTX 275 video cards (in "SLI-Activate all displays" mode). The slave machine has two NVIDIA GeForce GTX 9800 video cards (also in "SLI-Activate all displays" mode).

The scene I am using is pretty simple, it is the panorama scene.
panorama = viz.add('panorama.ive')

When I display the images to a LCD monitor, most of the time, all the screens (only 2 full panels can be seen, other 4 panels are partly blocked because the monitor resolution is 1680x1024, while the virtual screen is 2400x1200) look fine. When I rotate the HMD, the images on the monitor seems pretty good (no obvious breaks). But, occasionally, I still can notice some breaks in one or two of the panel images. In contrast, when look into the HMD, the breaks of the image is obvious (seen as moving lines from top to bottom across the screens) when rotating head abruptly.

That's really weird :confused:

[Zhi]

OK, now the problem is solved. The cause of the tearing artifact on the xSight HMD screen actually comes from the NVIDIA control panel settings. It is the setting of the "Triple buffering" under the "Manage 3D Settings" submenu that matters (refer to the attached screen shot). When set to "On", it will cause the tearing artifact in the xSight HMD. But if set it to "Off", the tearing artifact is gone.

Zhi