I am struggling with rendering a proper / credible appearance for an LED. I already got some help in the past with regards to the light not being visible (How to get LED light appearance right), and the appearance not being right but that was an SMD led and while not being photorealistic I can consider the actual result to be satisfactory: SMD Led

However, I used the same approach with this other component, and the results are poor (as I actually expected due to the nature of the approach I took).

Compositor settings and final image

Basically, I now have the need to flash an LED which is located within a shell (radio control) and have the light being transmitted outside through a gem (light guide) made of polycarbonate. I tried to create something similar by adding an emitting plane within the gem and then working with glow and streaks in the compositor, but the light seems to bleed out of the control shell rather than being project outside from the gem.

Here's the image without compositing:

Image not composed

and here's the one I settled with as I wasn't able to get the transparent plastic and the light streaks, which could even be ok to some extent, but it's not what I aim for:

actual compositing (Only glare node / glow setting without streaks / star, semi transparent gem

in this case there's no emitting plane inside /below the gem, but the emission is from the gem material itself.

Finally, this is more or less the result I'm aiming for: I know the shape of the plastic is different, but regardless this seems much more real than mine..

gem OFF gem ON

I have seen this answer but I can't seem to be able to set the mask right, if that's the only solution I will try to fix my compositor setting to match those advices but if there's another solution that could point me towards obtaining the desired result I'd like to put it in practice (starting from the gem material settings - IOR, transmission etc. - all the way to compositing masking etc.)

Unfortunately I can't share the source file but if it's "mandatory" I can slightly modify it and post a stripped down version.

Thank you to everybody.

  • $\begingroup$ How have you created or set the mask for the emission? I don't understand the last part of the second linked question ("You need to add an object index value to the object and use this as a mask in the mix color node to only add the glow effect where the object is, this will make it seem like it goes throu the object and not throu the air too."). When I paint an emission map I get this => i.stack.imgur.com/feSzg.jpg but I am not sure if you asked for this because there is not much plastic involved. $\endgroup$
    – Blunder
    Mar 26, 2022 at 1:59
  • $\begingroup$ Currently there's no mask involved, at I tried to follow the instructions I linked (the ones talking about the index value) but never came up with anything usable. Either the mask had no effect, or it completely screwed up the image appearance. $\endgroup$ Mar 27, 2022 at 7:39


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