[dd_]

another test, i shall set one up to compare the pattern based on the ref you have just shown mate give me a mo(ish)

[ivox3]

Now your just getting crazy. ..... j/k.


Awaiting the comparison .......

[dd_]

im going to move the light closer but this is the intital test

[dd_]

not closer but i tweaked the cavity

[glebe digital]

These are fantastic tests guys!!!!!!

[dd_]

another pattern comparision



i shall play some more

[dd_]

this is the current deal with the LED im using so if anyone has any ideas where to go next please feel free to let me/us know
key:
red = emitter
yellow= metal reflective cone (found on the LED i have on my desk), just found out that removing this does nothing to the effect so its not needed
blue = cavity
rest is solid with an IOR of 1.5

[lebbeus]

@dd: these are awesome…is the cone just a random shape, or is it some kind of carefully constructed optic geometry (parabola, etc)?

@ivox: thanks; I'll flip them around, but I don't think there's much coming out the top due to the parabolic curves--they're like mini downlights right now I also think my emitter is screwy.

[dd_]

the cone is just a cone with an ali metal tag on it, but as i have said it does the same without it. the cone on the cavity is just another cone
the only thing i am having issues with is the cats eye thing where the only way to see the colour on the LED is for the camera to be bang infront if it, if viewed from an angle you cant see the colour on the led itself. im playing some more so stay tuned :/

example

[dd_]

right this is the last one for the night
i finally got some light at the end of the LED, combination of adding a small amount of roughness and other tweakage
i have also uploaded the maxwell file if anyone wants to play

http://www.max3d.org/maxwell/LED10.rar

[Thomas An.]

.... I'm not just going to model a cube, because I don't think it's accurate. Maybe an offset surface of the primary dome with an imperceptible air cushion between the two ....... ??

Chris,

It should be a plain cube as the illustration shows. Note in that illustration how they show the blue ray having total internal reflection ! They anticipate a flat surface right above the emitter element.

Also (as Tom mentioned) ... the cavity represents the emitter/epoxy interface. This is what tells maxwell that a ray is inside a dielectric.

If you were to merely stick the emiter imside the dielectric dome (without creating a cavity) then the result is "nothing". A ray of light will start and then hit the inner side of the dome; signifying that exits something ... but it doesn't know what it exits from ... because it never knew it was IN something. A ray needs to pass TWO dielectric surfaces to be complete. It needs to pass an incident and a non-incident face to know that it entered and exited (this is how it is in real life as well)

Think of it this way: If you stick your finger in a glass of water you are basically creating a water surface around your finger (the water surrounds it). If you stick the LED electrodes in liquid epoxy .... the epoxy surrounds and tightly hugs the electrodes giving you the impression that there is no cavity ... but there is ! ... it is just very tightly formed to the shape of the object you put in.

[glebe digital]

right this is the last one for the night
i finally got some light at the end of the LED, combination of adding a small amount of roughness and other tweakage
i have also uploaded the maxwell file if anyone wants to play

Thanks Dave, I'm going to have a look at your setting later tonight.
I'm starting to realise that roughness in the epoxy is probably important......bit slow on the uptake but mind was on other things today.

BTW, your progress is looking way nice.

[markps]

.... I'm not just going to model a cube, because I don't think it's accurate. Maybe an offset surface of the primary dome with an imperceptible air cushion between the two ....... ??

Chris,

It should be a plain cube as the illustration shows. Note in that illustration how they show the blue ray having total internal reflection ! They anticipate a flat surface right above the emitter element.

HI Thomas, I've been breaking apart a few different LEDs and I've found that all of them have a semi-sphere cavity and not a squared cavity. And all the cavities are very small. just enough to cover the emitter.

Does it sound right?

[dd_]

from the tests ive done tonight and today i can say that leaving the cavity as air works and making it another dielectric mat doesnt :/
i can say that the cavity being square or round doenst do anything to the render (ive rendered and seen no change sorry )
from the refs and the LEDs ive got infront of me i would say copying them doesnt work either. as none really show as the illlustration . i would say that we need the cavity as shown in my screen grabs to make it give the same effects as the real world . apart from the light hitting the end if the LED
but some noise helps this
i can only say this from a do approach but i shall try and experiment some more

[jalokin]

Hi,

Wanted to join the testing but encountered a problem. it seems like it's only possible to create white lightsouces and if i use colored emitters the source appears white but the reflected ligt is colored. is that correct?

And when i try to use the xyz cordinate i cant render anything, it newer starts the voxelization.