General line-of-sight question

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jwilde 101 Feb 12, 2008 at 01:22

Hi,
I’m new to this field and am evaluating whether to use a game engine to solve geometric line-of-sight type problems.

My problemis to take a small VRML or X3D model (less than 1 square mile, an urban type environment) and a set of points in the model, and I want to be able to know, for each point, the list of all other points that have an unobstructed line-of-sight to that point. It seems like one way to do this might be by defining an illumination source at the point of interest and seeing what other points have been illuminated. Since I don’t have experience in this area, I’d like to start with an engine that is fairly easy to get up and working quickly. Does anyone have suggestions on where I should look? There seems to be a lot of packages available so I’m not sure where to start. I spent some time looking at the well-documented OGRE API and tutorials, but I’m wondering if there might be an even more straightforward approach.

Thanks for your advice,

John

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Reedbeta 167 Feb 12, 2008 at 06:57

It sounds to me like a game engine would be inappropriate for this task. Possibly what you want is a ray tracer - you just need to check for intersections of line segments (between pairs of points) with your scene, which is very similar to what a ray tracer does. Maybe you can take an open-source ray tracer and just call its intersection-testing routines yourself, bypassing all of the lighting and shading stuff.

Finding intersections like these is indeed a part of calculating illumination, but there’s not really any reason to actually calculate illumination here. Also, real-time graphics/game engines like OGRE work in a completely different way that’s not really suited for this problem (though they might also have intersection testing routines built in for various other purposes).