LED Strip and noise levels

[Jpjapers]

Im working on a project that features hundreds of meters of LED Strips all of which are curved as they are around the outside edge of a racetrack. The only way i can currently achieve this is with a light material. However the light material warns users against using it as a main scene light source. The scene has dozens of overhead corona lights but The scene is also heavily influenced by the light from these led strips and is of course super noisy because of this.

Is there a better way of doing this?

[TomG]

Scatter actual lights along a spline? Also the Light Material should be fine used as a main light source, it's Self Illumination in a Physical Material that shouldn't be used as main lighting. In fact Light Material performs the same as an actual light of that shape, except in the case of spheres as the Spherical Light is a mathematically perfect sphere so can be calculated faster.

[maru]

However the light material warns users against using it as a main scene light source.

That's not true. Self-illumination in a Corona Physical / Legacy material has this warning.
Actually:
- if the LEDs are just going to "glow" as in "appear as something bright" then you can use self-illumination
- if the LEDs are going to illuminate scene objects with strong light, then LightMtl or Corona Lights are the way to go

[Jpjapers]

Hmm ok my mistake. My second question then would be whether there are any under the hood changes that could help with the noise in this setup?

[maru]

Depends where the noise is coming from. Is it from direct lighting? Or some bounced light? Maybe there is a reflective surface somewhere close to the lights?

[Jpjapers]

Depends where the noise is coming from. Is it from direct lighting? Or some bounced light? Maybe there is a reflective surface somewhere close to the lights?

The noise is coming directly from the LED light. The reflection on the floor is very noisy. The floor has some high frequency detail in the bump but isnt very glossy.
After 100 passes the noise is still prevalent sitting at around 12% in the VFB.

[maru]

Corona Lights and Corona Light Mtl should be sampled efficiently, I would not expect noise after 100 passes. Could you share an image or the scene itself? Here or over at https://support.chaos.com/hc/en-us/requests/new

[Tanner]

I wonder, is the LED sitting behind or within another glassy material, so the light emitted has to transmit through a volume, no matter how clear?  If so, you may be better off eliminating this "clearcoat" or using a two-light setup. You keep your LEDs as you have it within this strip (if is modeled accurately like how a consumer-grade LED strip is made) but disable emit light. Duplicate and push these lights out so they're beyond the extents of the original geometry slightly. Check ON emit light for these but disable (uncheck) all of the Visibility parameters, including Occlude Other Lights. This way you can also tweak the strength of the original LEDs if they were too bright with Bloom/Glare, and you can always boost the actually emitted material if it wasn't bright enough before. It will be invisible in the rendering but it will fake your set up.

I do something similar for my street light fixtures that have LEDs or bulbs behind glass but I need the emitter object or a light object with an IES to drive the main light in the scene and the LEDs/Bulb to be the visible part.