IES Lights no visible in refraction - Daily Build 30/08/2018

[Dionysios.TS]

Hi all.

I think I found a weird thing and probably a bug.
Since I installed the daily build 30/08/2018, every time I use a Corona light with an IES file loaded and I see it through any glass, the light body is not visible when the view angle is near to 90.
It seems like refraction "disables" the black appearance option of the light. If I turn on Thin Wall in the glass material everything works fine.

I uploaded a small crop of a test image where you can see the lights behind the glass are black!

I am looking forward for your news.

Thanks,

Dionysios -

[maru]

Are you sure it was different in some older version?

[Dionysios.TS]

It never happened to me or at least I never noticed it.

We do a lot of arch viz here and we use always a lot of glazing elements with IES lights behind, I never noticed this before.
As I always use the daily builds for our production images how can I check if this happenes with older releases as well? I need to install an older one and check. :(

You don't have any clue if this behaviour is normal or not? Physically is not.

Thanks for getting back!

Dionysios -

[maru]

Here is the same scene rendered in V2 and 30.08 V3 build. Note that the "prevent black appearance" option in the Corona lights does not work on refractions and reflections. This was reported multiple times, but according to our devs, it would be much better to fix it, than to introduce additional fakes.

The workaround for now is to use separate object for light emission (invisible light which emits the IES shape), and separate object for the light object (e.g. glowing disc with self illumination or light mtl with "emit light" off).

[Dionysios.TS]

Here is the same scene rendered in V2 and 30.08 V3 build. Note that the "prevent black appearance" option in the Corona lights does not work on refractions and reflections. This was reported multiple times, but according to our devs, it would be much better to fix it, than to introduce additional fakes.

The workaround for now is to use separate object for light emission (invisible light which emits the IES shape), and separate object for the light object (e.g. glowing disc with self illumination or light mtl with "emit light" off).

oh... So strange we never noticed that before and actually is a big limitation.
Thanks a lot for testing and the solution you proposed was the one I thought initially too.

Thanks again and I hope sooner or later this will be resolved.

Dionysios -