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View Full Version : Why doesn't LW contain air to begin with?



Johnny
08-26-2004, 01:56 PM
I'm pretty comfortable finally with making air polys for glass things, but I wonder, why doesn't LW assume there's Air in a scene, anyway?

Could there be a "World" IR value..so that if you're in space, you could globally take out the air, or if underwater, make the IR water?

I'd guess that *most* scenes modeled take place where there is air, whether earthian, martian, venutian, or klingonian.

just wondering..

J

UnCommonGrafx
08-26-2004, 02:49 PM
You do understand the ramifications of your question, right? The one that comes to mind for me is the question: why should a 3D program you build things in assume anything about your process?

It doesn't and can't 'assume' those 6 sided polys you just put together should have rivets, bolts, etc. That's your job.

Thank goodness there are scripts to do it automagically. Edit--> Add air poys, that is!

Johnny
08-26-2004, 02:58 PM
I can see/respect the notion that the app not make assumptions about what I'm after...

What I was thinking, tho, was a user-settable index of refraction for the space, sort of like there's a global ambient light setting, one whose value can be changed, or turned off essentially by typing 0.

j

ingo
08-27-2004, 02:20 AM
Well since Lightwave is a "dumb" software that only knows polys even that doesn't help a lot me thinks. Its only useful for softwares like for example FormZ, where a cube is a cube, and not a bunch of polys loosly fitted together. And since LW didn't know the inside from the outside how could that help ? And the "ambient refraction" you like to have exists, its simply 1.0 .

My two philosophical cents

Lightwolf
08-27-2004, 03:17 AM
Well, LW actually knows that the scene is in air, this is why refraction actually works the way it does. For example, for the first hit (from world/air to object), it takes the ior of the air (1.0) and your object to properly compute the refraction (the direction of the refraction is a function of the incoming ray, angle of the ray to the surface and the in and out ior).
Unfortunately, there is no way to set the world ior though (think underwater scenes for example).

So, LW contains air to begin with ;) (except for the box I got, which was stuffed with a T-Shirt ;) ).

Cheers,
Mike

pauland
08-27-2004, 07:47 AM
[QUOTE=Johnny]I'm pretty comfortable finally with making air polys for glass things, but I wonder, why doesn't LW assume there's Air in a scene, anyway?
[/QUOTE

How would they do all that space stuff with air? ;-)

Lightwolf
08-27-2004, 08:36 AM
Could there be a "World" IR value..so that if you're in space, you could globally take out the air, or if underwater, make the IR water?

Well, it wouldn't make much of a difference in space, the ior for that is close enough to the default (actually, the other way around, _air_ is close enough to the default 1.0).
It would be nice to be able to set an initial ior though, agreed.

BTW, I did have this verified by a LW developer a couple of years ago.

Cheers,
Mike