Smooth LED lighting

How do teams like 118 (2013) and 4488 (2014/2015) achieve relatively smooth lighting effects with LED lights, i.e. diffusing light so that individual LEDs are less discernible? Is this just a product of a neat hole pattern that obscures parts of the LEDs?

118 in 2013 for reference
4488 in 2015 for reference

Looks to me like they are behind a slightly frosted panel with LEDs on the top and bottom. Indirect led lighting is awesome.

They would put a strip of individually-addressable LEDs behind a frosted or matte panel, which would create the “blur” effect. I’d recommend a 60 or greater pixel-per-meter density for best effect. Pololu makes some good weatherproof LED strips.

Don’t know for sure, but I always assumed they used a thin (like 1/16") white acrylic sheet as a diffuser.

I was talking with a member of 4488, the use this to diffuse their LEDs.

As said above, we use some thin diffuser paper taped to the inside of the rail behind the cutouts. The LED’s are 60 led per meter NeoPixel strips, which are affixed along the inside of the rail for the entire length, which allows them to light both sides of the rails, which have cutouts.

How do you get them to sit evenly behind the rail? I would think that they would easily wrinkle or bend enough to distort the light.

The diffuser sheet is taped tight at the ends, with some small pieces of double sided tape in the middle at some of the cutouts to make sure it sits flat. And the lights are double sided tapes every foot or so along the lenght to make sure they sit flat. Plus far away you won’t notice any distortion. We also run pneumatic and power wires up the same rails, and if you look up close you can see the shadows from them in the lights. However from more then 3 feet away its not noticeable.
we used a rail with a snap in diffuser like this