I just helped a Brazil user with this one and thought it might interest other render geeks!
“A glowing filament is a complex effect but here’s a sample file I just made to help explain how I’d do it. The filament itself has a Brazil Advanced Blend material between a Brazil glass (IOR of 1 and no highlight) and a Brazil Brightness material. The texture used to transition between them is a gradient of white/black/white with a custom curve applied for the gradient transition. The texture mapping of the pipe is left as the default of surface UV so that the gradient runs along the length and blends out to transparent. The actual light from the bulb comes from a point light though and the highlight parameters through the glass of the bulb create the glow. The point light is adjusted with several advanced settings including decay and shadow focus override. Depending on the view rendered, you will need to adjust the point light location to line up just right with the filament.”
bulb.3dm (1.2 MB)