Author Topic: Light beam not rendered correctly with fog  (Read 5266 times)

2021-07-25, 21:27:51
Reply #15

Basshunter

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Thanks for your quick reply Tom. By disabling "Adaptive Light Solve" the problem with the big chunks not being rendered correctly seems to be solved. This was not the case when using Corona 6 in my first posts, for some reason.

I'm still concerned about the amount of noise in the image. Is it normal?

On the other hand, Corona Render Help Desk says this about adaptive solver:
"The results produced with the adaptive solver enabled are always less biased (more realistic) than with the adaptive solver disabled."

In my case, how would not having this option enabled affect the realism of the scene? Would you mind elaborate a bit further?
« Last Edit: 2021-07-25, 21:47:03 by Basshunter »

2021-07-26, 13:30:31
Reply #16

TomG

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Noise is expected as the calculations for volumetric lighting are more involved, so will take more passes (or heavier denoising) to clean up.

Shouldn't affect the realism here at all, that's more about light bouncing from HDRI env maps etc. so more like your conventional interiors. The adaptivity has a look to see "how intensely does this block of the image need to be rendered?" and then allocates processing power accordingly. The drawback can be, though, that if "not enough volumetrics" appear in a particular block, adaptivity decides it doesn't have that much hard work to do there so doesn't allocate as much processing power - this is why you see the squares in your image, those are the blocks that adaptivity divided the image into (as a future pointer for when disabling it may help :) ).

Hope that helps!
Tom Grimes | chaos-corona.com
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2021-07-27, 16:46:17
Reply #17

maru

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@Basshunter - here are my recommendations:

option 1) Use 3ds Max native lights instead of Corona lights (if possible). Corona lights are more realistic, they always have some area, they have directionality, etc, but that makes them harder to render. 3ds Max lights are "fake" but they will render faster. I am not sure if it is possible to make 3ds Max lights have a visible disk shape rather than always being shot from a point, which may not work for you...

option 2) Disable Adaptive light solver in the Performance tab - looks like currently there is some issue here and this should be improved. The scene might render a bit slower but you will immediately get rid of the square artifacts.

option 3) Leave the Adaptive light solver enabled, enable the Development/experimental stuff rollout (this: https://coronarenderer.freshdesk.com/support/solutions/articles/12000021288 ), scroll down to "Lights" and change "Solver" from the default "Select automatically" to either "Better object-based" or "Scalable". Both seem to be working fine and without the square artifacts.

I would also advise increasing the Light Samples Multiplier to a higher value than the default 2 (probably ~4 will do the trick).

Attaching some example images and will send you scenes in PM.

Marcin Miodek | chaos-corona.com
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2021-08-05, 04:12:47
Reply #18

Basshunter

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Thanks for your help, Maru. Really appreciate you took the time to check the scene.

I'll probably go for option 2 or 3 since I need the most realistic result possible this time. Hopefully in the future we'll get faster rendering of volumetrics.

2022-10-05, 00:00:44
Reply #19

Basshunter

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option 2) Disable Adaptive light solver in the Performance tab - looks like currently there is some issue here and this should be improved. The scene might render a bit slower but you will immediately get rid of the square artifacts.

option 3) Leave the Adaptive light solver enabled, enable the Development/experimental stuff rollout (this: https://coronarenderer.freshdesk.com/support/solutions/articles/12000021288 ), scroll down to "Lights" and change "Solver" from the default "Select automatically" to either "Better object-based" or "Scalable". Both seem to be working fine and without the square artifacts.

I would also advise increasing the Light Samples Multiplier to a higher value than the default 2 (probably ~4 will do the trick).

Attaching some example images and will send you scenes in PM.
[/quote]

Hi Maru.

Do you know what happened to the adaptive light solver you mentioned in option 2. I still have the same problem that lead me to create this thread.

2022-10-05, 01:02:40
Reply #20

dj_buckley

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It was moved to the Development/Debug menu, which is hidden, so you have to unhide it through the Corona System Settings.  Then you'll get an addtional rollout on the Performance tab, where you'll find the Light Solver.  I'd also like to know why it was moved there but kept on by default?

2022-10-05, 05:07:02
Reply #21

Basshunter

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I'd like to re-open this conversation since I'm experiencing this problem again. For some reason Corona seems to struggle when rendering lights with very narrow directionality in foggy scenarios. Specially the portion of the light beam that near the source. I've tried disabling adaptative Light Solver but the problem persists.

As you can see in image # 1, even after 10 mins the portions of the light beam near the source don't render. Image # 2 shows how even after using a very small region render, these portions have problems to be rendered completely.   

This is a big problem for us since as mentioned before, we do lot of stage rendering where moving heads and fog are the main thing. With this problem, even delivering some descent previews is almost impossible.

2022-10-05, 14:11:32
Reply #22

Basshunter

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Even after almost 8 hours the engine seems to have problems rendering the image. Note how on many portions of the image, the light beams were not rendered correctly.

To make things even worse, look what happens when I turn Bloom and Glare On (3rd image)
« Last Edit: 2022-10-05, 14:17:20 by Basshunter »

2022-10-12, 15:15:28
Reply #23

GeorgeK

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This is a tough one, the light beams should eventually clear out but it might take long depending on hardware. As for the bloom and glare issue it's quite sensitive under certain conditions and it can lead to that, we have it logged.

Regarding your case, I would personally fake it with corona light mtl & geometry, but someone might be able to give you a better alternative. I can send you a scene if you are interested in the fake solution.

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« Last Edit: 2022-10-12, 15:27:58 by GeorgeK »
George Karampelas | chaos-corona.com
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2022-10-14, 03:16:52
Reply #24

Basshunter

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Hi George. I guess there's no better solution for now so I'll take a look at that fake version if you send it. Thanks for your help.

2022-10-14, 10:48:35
Reply #25

GeorgeK

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Hi George. I guess there's no better solution for now so I'll take a look at that fake version if you send it. Thanks for your help.

I hope it can help you, granted quality wise is not that great but with a little tweaking and better masking (other than gradient ramp), you can pretty much have an optimal fake that renders relatively fast. Also do check lightmtl light emissions to see if you can further improve performance by disabling them.
George Karampelas | chaos-corona.com
Chaos Corona QA Specialist | contact us