Twilight Render User Forum

Perhaps someone has already done this, but I haven't found a source yet. I'm trying to make some Edison bulbs that are light emitting, but also show the glowing filaments. So far I've tried things like:
- Creating a bulb (no volumetric glass, just 0-width) assigned with Architectural Glass (No Shadow or Common), or no glass at all.
- Adding a point light inside or just below it.
- Adding a couple simple thin-and-tall rectangles set to light emitters with the color orange, high intensity, to simulate glowing filaments. (I was hoping I could do something like a 10000 W/m^2 emitter with a inverse-quad falloff, but I didn't see falloff setting for emitters.)

So far I just can't seem to get that glow on the filaments -- I have ideas about placing an emitter behind an SSS-material entity of the same shape that's a component that will always face the camera, but haven't tried that yet. I'm also a little concerned about doing more complex filaments that will greatly increase my render time, particularly with SSS. (There's several frames of a chandelier that has a bunch of edison bulbs.)

The closest I've seen is something like: http://twilightrender.com/phpBB3/viewto ... ent#p25201
but I was hoping to do it without post-processing, since I'd have to apply that to all the edison bulbs in each of the frames. Advice appreciated.

Thanks,
-B

If you are using one of the photon map settings (Low/Low+ through High/High+) make certain you set your filament to Fake Emitter!

Your approach sounds good, and certainly where I would start. Again, though, if using a photon map setting having "a bunch of bulbs" each with their own point light inside, that might be a RAM and time killer. Depends on how many you have. You might need to try to fake the lighting for the entire chandelier as a whole.

So, it looks like adding a SSS volume in front of the filament didn't buy me much but additional rendering time. It might be useful to do if you want to do a close-up of a bulb, to get sort of a diffuse glow around the filament, but I found that I could get acceptable results for my purposes by messing more with the bulb than the filament lighting. What I did:
- Create a surface-only bulb and assign it something like Architectural Glass Common or No Shadow. I used Architectural Glass Common as a base, then changed it to a flint-glass style IOR (~1.66), and adding a an orange-gray tint to it.
- Drop a point light inside of the bulb.
- Create a your filament(s) as components(s) that always face the camera (this makes it so you don't have to have a multi-faceted filament, saving rendering time, since you're mostly using the filament for decoration and not lighting -- the point light does that -- you just want some reflections on the glass clear bulb and ambient coloring), make it a light emitting material, give it a color (I used a yellow-orangish color) with some insanely high W/m^2. I used 1,000,000. This is because the surface area of the filament is so small; see the twilight manual for how to calculate the value for your filament.
- Drop your filaments inside the bulb -- mine intersected with the point light, which doesn't appear to have produced any artifacts, but I did make sure that neither my point light or emitters intersect with anything. I assume artifacts are due to something like light point values evaluating to 0 or Nan for 0-length distances, but since these are both light sources, they are already the color of the light source. If you have very dim lights I suppose it could be a problem.

Attached is an easy-10 50-pass rendering of the results -- the models is a little bit quick-n-dirty, but it should illustrate the basic idea:

didn't someone create this effect with a .png file for the filament?

Subject: Lighting: "transparency" of the lampshade

Subject: Matte Lampshade Material Library (39 colors)

Subject: Glass Lampshade Material Library (37 colors)

Subject: Antique Light Bulb Glowing

Fletch wrote:some inspiration from the LEGENDARY Jenderzych

what you are seeing as glow is the result of a hot filament, and the exposure of the camera setting creating the glowing look.
you can try to model the glow... I'm not sure.