[Radiance-general] Rendering for off-centre presentation in a VR lab

[P George Lovell]

Hi Everyone,

I'm attempting to use Radiance to generate images for presentation in a 
large VR space - the system currently uses a game-engine but I'm not 
happy with the quality of the rendering as I'm interested in the visual 
perception of shadows and shading.

The space* is approximately a 6x6x2metre volume with a stereo 
(polarized) screen at one end, the screen is roughly 6x2 metres.


I want to present a rendered scene as if it lies behind the screen, i.e. 
the screen is a window through which we view a rendered object. The 
viewer can then walk through the space and I can present updated views 
relative to the current viewing location (I have 6 DOF head tracking). 
Obviously this requires a lot of offline rendering and a relatively 
narrow movement range - just to cut the rendering overhead.

It's easy enough to see how I might render images for presentation when 
viewer and the viewing target are positioned centrally within the world, 
i.e. looking straight forward towards the middle of the screen. What I 
don't understand is how I render scenes for when the viewer has move 
off-centre to left or right. Firstly, perspective is going to make one 
side of the screen smaller than the other, I'd need to correct this so 
that the screen image fits on the actual screen.

I think I could build-in some markers that denote the corners of the 
large VR screen, then stretch the image so that these markers lie on the 
corners of the screen - this seems a little clumsy.

Is there a better way?

George


*<http://www.abertay.ac.uk/about/news/pickoftheweek/2010/name,5454,en.html>



-- 
Dr P. George Lovell,

Lecturer in Psychology
University of Abertay Dundee
Dundee
DD1 1HG

Tel 01382-308581
Fax 01382-308749

Researcher/Co-investigator,
School of Psychology, University of St Andrews

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