First dimensionally accurate model a 16 led Neopixel ring from adafruit to OCD level 1 because you can...

http://www.adafruit.com/products/1463

The led

https://fusion360.autodesk.com/projects/ws2812

The ring

https://fusion360.autodesk.com/projects/neopixel-r...

Then define a body space gap with the model so you can use it as a boolean operator against the piece you wish to mount it in.

Design a test piece to test the body space fit.

Print it, low material use compared to final part, so you can afford to iterate...Be amazed when it fits like a glove the first time.

Model it directly into the target part...

Print it ready for integration. Shame the print is not quite as glassy...

Prototype your electronics.

Stick it in and press go... Very hard to video....

No easier to video when in the helmet, trust me, it looks fab...

Of course this means I will have to place an Arduino nano into the helmet peak next to the 9 volt. Good thing i already have a model for that!

to be continued.