A visible light

[SacSurfin']

Your lighting effects and shadows are great, but I'd like to see the light the lighting is cast from. Actually setting a visible light in a lamp or porch light would be great.

[Dave Donley]

Hello SacSurfin':

If you want to see a bulb, create the bulb shape and give it a texture that uses a Constant Reflectivity shader and has the Cast shadows checkbox turned off.

For a lampshade, use the Translucency Reflectivity shader with any color shader for the pattern; adjust the Translucency slider downwards for lees of a glow from the lampshade.

[SacSurfin']

That works somewhat but to be realistic it needs a glow to the light, when I see light in life I see a glowing circle of light not just the shape of the bulb

[propstuff]

Is this the sort of thing you mean?

N.

[Dave Donley]

Hello again SacSurfin':

RW doesn't render glows, so yes, you will need to add these as a post-processing using PhotoShop or other. Or, pay Nicholas to add the glows for you!

[SacSurfin']

Nicholas, you didn't happen to do that in VW did you?

[propstuff]

quote:

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Originally posted by SacSurfin':

Nicholas, you didn't happen to do that in VW did you?

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Yes, as it happens. ;-)

The reason RW doesn't have lights that glow is -to quote Strawberry Fields: "nothing is real".

You see a glow when you look at a light because photons are being emitted directly from the light at your eye. "All" other light coming from objects is the result of light being reflected from light sources, and other surfaces.

Computer lighting can calculate and reproduce those reflections (transmission, refraction etc) to varying degrees, but what no computer can do is fire large amount of photons directly out of the screen at you. (only the regular screen emmission.) More sophisticated (read expensive) renderers that offer those kinds of effects are (I'm guessing) faking it in the same way that Photoshop fakes lighting effects. There's no light sources in Photoshop, just an algorithm that describes the effect that light sources would have on an image.

So, I reasoned; what was needed was something that would produce a "glowing" halo around the edge, feathering away to nothing.

That meant; a circular (for instance) gradient, a transparency, and a glow.

The steps were;

1/A radial Gradient, white to dark grey, on the same dark grey background.

2/Export the gradient as an image. (I think I used a TIFF)

3/Import the image back in to use as a Transparency Mask where the centremost part is opaque, and the outermost is transparent.

4/Create the texture using the Constant Reflectivity (the "glow") and the Mask Transparency (the feathered gradient)

5/Create a 3D disk to take the texture. (I used a circle extruded to 0 thick) and map the texture on to the centre of it so they are the same size.

Now the fiddle; orientate the disk so that it's between the light object and your viewing position, and directly facing you. then scale it to an appropriate size. (This will be entirely dependant to your view point, position, distance etc, etc.

BTW, the light bulb itself had a plain Transparency and a glass Reflectivity. This could be tweaked a lot.

Dave, I'll send you the file if you're interested, but I'm guessing you could make your own if you wanted. ;-)

cheers,

N.

[ 09-10-2004, 01:34 AM: Message edited by: propstuff ]

[propstuff]

Dave,

it just occured to me that this could be quite a practical trick if the glow object could be made to behave like an image prop that always orientated itself towards the viewer -except in 3D; not just stuck on the working plane.

I'm not sure how this could be done though. Any ideas?

N.

[ 09-09-2004, 05:55 PM: Message edited by: propstuff ]

[SacSurfin']

Thanks Propstuff, I've been stumped on this one for a very long time.