Author Topic: Fireflies with HDRI  (Read 1919 times)

2018-10-02, 14:23:20

dj_buckley

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As the title suggest, I just can't seem to get rid of fireflies when using an HDRI - never had this issue before, seems to be a Corona 2 issue.  Using 1714 from Peter Guthrie.

The material isn't too reflective and blurring stuff isn't an option.

Anyone else experiencing the same thing - it's almost making HDRI's unusable for me on exteriors

2018-10-02, 14:38:27
Reply #1

TomG

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More information would be very useful - a render (or part of a render) showing what you are seeing, a look at the render settings, the materials, and whether you are using the new experimental light solver or not, etc. Of course all that is best done with the scene itself (and that can be sent privately with the private uploader https://corona-renderer.com/upload). Also, it would be interesting and useful to see the result as rendered by an earlier version of Corona, to determine whether this really is something different with Corona 2 or not.

Have you tried the Corona 3 daily builds too, to see how things work there?

Thanks!
   Tom

2018-10-02, 15:48:36
Reply #2

dj_buckley

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Hi Tom

Let me test a few things my end, testing daily builds is too risky for me on a live job.

I have a feeling it's a dodgy corrupt scene.  Gonna try merging things into a new one and reloading hdri's etc.

I'm not using the new light solver - should I be?

2018-10-02, 15:52:59
Reply #3

TomG

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On the new light solver, safest not to be using it :) It is still experimental at this point and can still have artifacts etc especially in Corona 2 (improvements are being made in the daily builds). Was just one thing that may be a factor so good to know what you were using!

2018-10-03, 00:50:38
Reply #4

Crazy Homeless Guy

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As the title suggest, I just can't seem to get rid of fireflies when using an HDRI - never had this issue before, seems to be a Corona 2 issue.  Using 1714 from Peter Guthrie.

The material isn't too reflective and blurring stuff isn't an option.

Anyone else experiencing the same thing - it's almost making HDRI's unusable for me on exteriors

Are you overriding you reflection slot with a different HDR?  Or using the same one for GI and reflection?

2018-10-03, 10:10:14
Reply #5

koubankeo

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As the title suggest, I just can't seem to get rid of fireflies when using an HDRI - never had this issue before, seems to be a Corona 2 issue.  Using 1714 from Peter Guthrie.

The material isn't too reflective and blurring stuff isn't an option.

Anyone else experiencing the same thing - it's almost making HDRI's unusable for me on exteriors

Are you overriding you reflection slot with a different HDR?  Or using the same one for GI and reflection?

Using different HDR for reflection is the wrong way?
Thanks

2018-10-03, 12:32:45
Reply #6

sprayer

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no but you can not see how one hdri  was over brighten. with wrong settings hdri can produce noise. Also are  you using corona bitmap loader?

2018-10-03, 16:55:45
Reply #7

dj_buckley

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As the title suggest, I just can't seem to get rid of fireflies when using an HDRI - never had this issue before, seems to be a Corona 2 issue.  Using 1714 from Peter Guthrie.

The material isn't too reflective and blurring stuff isn't an option.

Anyone else experiencing the same thing - it's almost making HDRI's unusable for me on exteriors

Are you overriding you reflection slot with a different HDR?  Or using the same one for GI and reflection?

I had a HDRI lighting the shot and then a copy of the HDRI with a lower output in the visibility and reflection override

2018-10-03, 16:57:37
Reply #8

dj_buckley

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no but you can not see how one hdri  was over brighten. with wrong settings hdri can produce noise. Also are  you using corona bitmap loader?

Yes using the Corona bitmap loader.  See above for setup in reply to Crazy Homeless Guy.  Basically I can get the lighting to look good using HDRI and exposure etc, but this often results in reflections being overbright and the direct visibility of the HDRI, so I often use a secondary version tweaked for direct visibility and reflections

2018-10-03, 16:58:20
Reply #9

dj_buckley

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As the title suggest, I just can't seem to get rid of fireflies when using an HDRI - never had this issue before, seems to be a Corona 2 issue.  Using 1714 from Peter Guthrie.

The material isn't too reflective and blurring stuff isn't an option.

Anyone else experiencing the same thing - it's almost making HDRI's unusable for me on exteriors

Are you overriding you reflection slot with a different HDR?  Or using the same one for GI and reflection?

Using different HDR for reflection is the wrong way?
Thanks

There is no wrong way.  Whatever looks good right?

2018-10-03, 17:04:46
Reply #10

PROH

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AFAIK it's a known issue that a HDRi in the reflection override slot can cause (a lot) fireflies. You can solve this by clamping the reflection HDRi, but this gives somewhat more dull reflections.

I believe this is a bug, but untill it's solved, we're stuck with either dealing with fireflies or dull reflections. So I n cases where you don't absolutely need a different reflection HDRi than the one used for lighting, you should avoid using the reflection override.

2018-10-03, 17:52:55
Reply #11

dj_buckley

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AFAIK it's a known issue that a HDRi in the reflection override slot can cause (a lot) fireflies. You can solve this by clamping the reflection HDRi, but this gives somewhat more dull reflections.

I believe this is a bug, but untill it's solved, we're stuck with either dealing with fireflies or dull reflections. So I n cases where you don't absolutely need a different reflection HDRi than the one used for lighting, you should avoid using the reflection override.

Good to know I'm not going mad.  I guess I can get by using the Jpeg preview with a output boost

2018-10-03, 22:24:03
Reply #12

Crazy Homeless Guy

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I had a HDRI lighting the shot and then a copy of the HDRI with a lower output in the visibility and reflection override

This is a known bug.
https://corona-renderer.com/forum/index.php?topic=21255.msg132686#msg132686

What is odd if you use the same HDR instanced to the override slot it usually renderers cleanly...  I have had some luck doing what you are trying to do using the method shown in the attached screenshot.  I would be interested in hearing if this works for you.

I am getting fireflies in another scene where I am using this so it may not be a solution, but it is worth a try.

2018-10-03, 23:43:46
Reply #13

PROH

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Hi. Just a note on you setup: The use of a VRay HDRi map is another known source to all sorts of misbehavior.

2018-10-04, 17:56:18
Reply #14

Njen

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I still don't understand why people who use Corona are preferring to use Vray's bitmap loader instead of Corona's. Is it a lack of education?

[Edit] My 'education' question was directed at Render Legion, not the users, as in is Render Legion doing enough to educate their users on best practices.
« Last Edit: 2018-10-05, 05:00:42 by Njen »
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