Peerman
Posts: 46
Joined: Mon 25 Jun 2018 06:46

Global illumination reversed?

Fri 19 Oct 2018 07:10

HI, It would be nice if the GI got a big upgrade. Now when I turn off the ambient and only render with GI, the ceilings are brighter then the floor. It should be the other way around. In the screenshot you can see a simple interior made of boxes (all same material) and only sunlight. As you can see the lighting is way off. I know I can use a combination of ambient light and GI. But to have more realistic renders a good GI is a must I think. Also in your latest blog/movie (interior office) you turn down the GI and fake it with a decal on the ceiling. Although this is a workaround, it would be nicer to let the GI calculate that. Is it possible to have something in the next patch or v2 of 2019?

Thanks,

Best,
Peter
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iMac late 2017, 4.2 GHz, 32GB RAM, Radeon Vega 64, MacOS Mojave, TwinMotion 2019, Sketchup Pro 2018, Archicad 22

scott_norge
Posts: 6
Joined: Thu 8 Nov 2018 09:53

Re: Global illumination reversed?

Thu 15 Nov 2018 12:09

This is also happening with 2019-v2...is there another patch coming out soon?

JM_Koester
Posts: 7
Joined: Thu 10 Jan 2019 09:38

Re: Global illumination reversed?

Thu 10 Jan 2019 13:01

I dare say that it works as intended.
The resolution of the GI system is quite limited, if you turn down the distance, you will see that the bouncing light will become more defined.
Same as for shadow maps the resolution is constant, if you increase the distance, the result appears to be rougher.
I recommend to add some objects with a plain colour when testing GI, it helps to make the bounces visible, though I guess light just bounces once.

Peerman
Posts: 46
Joined: Mon 25 Jun 2018 06:46

Re: Global illumination reversed?

Fri 11 Jan 2019 07:24

I tried to create a Cornell box but the GI is only calculated for skylight and not for bounced light that is comes from a spotlight for instance. I think they should improve this. Maybe only calculate is for the final image upon exporting or something (similar like Lumion). If I have the time I can create it in the Unreal Editor as well to see how it looks there (without baking light).

Best,
Peter
iMac late 2017, 4.2 GHz, 32GB RAM, Radeon Vega 64, MacOS Mojave, TwinMotion 2019, Sketchup Pro 2018, Archicad 22

JM_Koester
Posts: 7
Joined: Thu 10 Jan 2019 09:38

Re: Global illumination reversed?

Fri 11 Jan 2019 10:39

A Cornell box without roof should work.
Imho the problem with calculating lighting on export (as in Lumion) is that is can look very different from the preview and your realtime setup, in which case you would need to setup two different light conditions, one for realtime and one for "offline rendering".
Right now you can maximise light and shadow in the export settings, not sure what it does exactly, but seems like the resolution and distance is increased. Tends to freeze TM thought, depending on the complexity of the scene.

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