Translucency

Translucency

I've been working on model of the light fixture in my bathroom. I'm perfectly happy with the model, now I'm using it to explore node textures.

The three shades on the fixture are frosted, white glass, too opaque to see through, but you can make out the light source within it.

Here, I started with the "Ocean" texture, tweaking the colors, carefully adding a bit of Emissive value and such.

I like the final effect (it lights the room well, and conveys the shape of the shade), but it looks like the entire shade is lit from behind instead of encompassing the light source. I wish it glowed from the center (where a light source has been placed in the center of the bell-shaped object). Any higher value for the Emissive setting and it blows out the entire space completely.

(I'm still getting used to the Falcon renderer.)

Does anyone have a different strategy for backlit semi-opaque stuff like this? Lamp shades, stained glass and the like?

You may already know this, but the effect you're after is best achieved by SSS, aka subsurface scattering. Cheetah does not have this feature as yet, although it is high on Martin's list. This feature has been discussed many times on the forums. If you do a search for "SSS" and also "subsurface scattering", you will find more information.

Sorry I could not be of more help. Good luck.

Theoretically this should be a simple matter of transparency blur.
No nodes should be necessary, especially not an "ocean texture".
Faking with emission could be a promising approach though.
But it turns out to be a very humbling experience for me, I just can't get it done with the Cheetah renderer.
Nothing behaves as expected: Transparency, reflectivity, area light visibility, let alone radiosity strength.

Well, yeah.

More luck with falcon though, there it looks not outright wrong, I suspect the new feature of filmic tonemapping helps a lot.
But the "realistic" approach" with glass thickness, huge ray depth and mirror refraction takes just very long to render (1000 samples still noisy).

I suspect there also is a photographic obstacle: When the lights are bright enough to illuminate the room, they will appear just plain white (clipped out).
When they are rendered to show the effect of lightbulbs shining through the shades the room turns out too dark.

I'm pretty sure that's what I would experience in my bathroom, aiming a camera at the lights.

A Photograph showing both effects I assume to be edited.
That could be done with Cheetah using HDR EXR output into Photoshop I guess.

Might this thread help you?

https://www.cheetah3d.com/forum/showthread.php?t=4137&highlight=ceiling+light#top

Podperson, peer, SurfingAlien, and frank beckmann
(excuse the expression):
“Shed-Some-Light” on this type of lighting.

My Best
Jeanny

misoversaturated

Click to expand...

I've done a little more experimenting, based on your file. The result still isn't perfect, but interestingly close.

I used a Membrane node with a noise node providing a texture to get this look. It's more transparent, but still obscures the details behind the shades. It's also a bit better at coloring the light that travels through it (there's a very pale yellow color to this test.)

Yes, ultimately subsurface scattering is probably what I'm after, but the falcon renderer seems to help provide a few nice options.

Thanks for everyone's help!