Author Topic: Corona Bump is so broken  (Read 7939 times)

2022-12-12, 15:32:56
Reply #15

dj_buckley

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I'd take accuracy over speed every time.

Or should I say "for an engine that has a strong focus on realism, i'd take realism over speed every time"
« Last Edit: 2022-12-12, 15:36:44 by dj_buckley »

2022-12-12, 16:07:37
Reply #16

Basshunter

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Hi all, first of all, I would really appreciate changing the thread title. "So broken" is not really true.
Corona bump looks completely off once you move the camera away form the object and you say it's not broken?

On the other hand, we are not getting many reports like this, so it can't be that bad. ;)
Wow

If you have some examples where the current behavior fails, please send them over - we are always happy to investigate, offer some workarounds, and log specific cases for our devs to review.
Did you even see the video?

2022-12-12, 16:12:44
Reply #17

dj_buckley

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Did you even see the video?

Lol, that was my first thought.  Erm .... every example

2022-12-12, 16:44:22
Reply #18

TomG

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Yes, the video was watched - it just helps speed things if you already have an existing scene where the problem is known to occur for sure, rather than have us set out trying to create something from scratch (also it often helps if it is a "real world" case scenario so we know we are testing within the kinds of situations users run into, versus "here's a teapot on a plane").
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2022-12-12, 16:45:55
Reply #19

TomG

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On the broken, it is not broken, it is as intended for render speed, so it was a choice we made back in the day. That said, sometimes that isn't the balance a user wants between speed and result, so we can take a look into the (non-trivial, actually quite complex) situation on what could be done instead.
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2022-12-12, 16:47:00
Reply #20

piotrus3333

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As @Juraj mentioned - you can just turn off tex filtering. This used to be my solution to this issue for years in VRay. I can't see how Corona would have more trouble with lack of filtering than VRay did.
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2022-12-12, 17:55:50
Reply #21

maru

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Hi all, first of all, I would really appreciate changing the thread title. "So broken" is not really true.
Corona bump looks completely off once you move the camera away form the object and you say it's not broken?

If it was "broken" then we would be getting tens of reports about it every day. It has been working like this since 2014 (or maybe even earlier) and still there are artists creating awesome works using Corona.

Quote
On the other hand, we are not getting many reports like this, so it can't be that bad. ;)
Wow
I agree.


Quote
If you have some examples where the current behavior fails, please send them over - we are always happy to investigate, offer some workarounds, and log specific cases for our devs to review.
Did you even see the video?

Yes, I watched the whole thing. Did you read my whole previous post?

Quote
Did you even see the video?

Lol, that was my first thought.  Erm .... every example

Once again:

- This is already reported. Our developers are aware of it. It is an issue and the current behavior can be improved - I completely agree.
- Let me repeat: If you have some examples where the current behavior fails, please send them over - we are always happy to investigate, offer some workarounds, and log specific cases for our devs to review.
- The more scenes and examples we have, the higher the chance the we will improve something faster. It has always been that way.


Thanks in advance!
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2022-12-12, 18:13:42
Reply #22

dj_buckley

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Maru - without getting petty ...

Your point about getting tens of reports every day is very naive.  We're busy people, I generally don't have time to sit and prepare scenes and log reports etc etc.  And when I do, it's at the end of the day and I just want to shut down for the day.  I'd guess a lot of people are seeing the issue but come up with their own workarounds/temporary fixes - this doesn't mean the problem doesn't exist. 

I've mentioned it a number of times in the past (including my own thread that I linked to with lots of examples querying the filtering etc etc). 

It's quicker to 'fudge' things ourselves, than it is to prepare/upload a scene, log a report and wait for a response/fix.  Admittedly we should make time to log reports after the fact, but using myself as an example, that can be weeks later, by which time I've forgotten about it because I "fixed" it myself weeks ago.  I then only remember it the next time I encounter the issue, but by that point I'm back at the start of the cycle and I'm mid-project, don't have time etc etc.  A lot of us don't have teams we can rely on to complete the work, while we spend days troubleshooting issues, so a temporary fudge is the next best thing.

Not only that, but some people either won't notice or won't care.  But again this doesn't mean it doesn't exist.

And yes, I did read your whole post, it doesn't mention the video or watching the video anywhere in it, so apologies for the incorrect assumption that you might not have watched it.

EDIT: I should have some time this evening, so I'll try and prepare an example
« Last Edit: 2022-12-12, 18:20:17 by dj_buckley »

2022-12-12, 18:56:47
Reply #23

Basshunter

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In fact, waiting for tens of reports before something can be called a problem or broken (you name it) is actually very unrealistic. Sometimes people can't just detect the source of a problem even when they feel something is wrong. Some of them don't even use this forum.

I have a wonderful designer on my charge and after checking that video, he mentioned that he had always felt something was wrong with the materials. He couldn't get consistent results after putting the assets in the scene. They just looked bland and too polished sometimes, even when he had just spent a lot of time tweaking them. But he didn't know exactly what the problem was. The same thing happened to me all this time too. We just couldn't tell what was wrong. We never imagined that Corona could be sacrificing so much accuracy and realism in order to make the engine faster.

 
« Last Edit: 2022-12-12, 19:29:18 by Basshunter »

2022-12-12, 19:24:19
Reply #24

dj_buckley

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I have another thread on here called 'Sharpness' or something along those lines.  It's the same issue but at the time I couldn't pin point it.  So Basshunter is right I guess.

I feel a lot of corona renders lack a certain 'clarity' and it's coming from things like this.

As I've already highlighted, when you're building and testing materials close in, you get them looking nice only for them to change in the final render.  When you've done this across an entire scene and then you zoom out for the final render it's quite apparent.

Why do zoom in on objects to build shaders?  Because I'm often looking at a physical sample in my hand and can put it as close to my face as I want to see the detail, grain, how it reacts to light at different angles etc.  I'm rarely building shaders whilst looking at a finished building/interior from the perspective of my CGI camera as a reference.

2022-12-13, 00:57:46
Reply #25

shortcirkuit

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Would have to agree here - i often comment to colleagues about how things look Muddy at times.  This puts some clarity behind the issue.


I have another thread on here called 'Sharpness' or something along those lines.  It's the same issue but at the time I couldn't pin point it.  So Basshunter is right I guess.

I feel a lot of corona renders lack a certain 'clarity' and it's coming from things like this.

As I've already highlighted, when you're building and testing materials close in, you get them looking nice only for them to change in the final render.  When you've done this across an entire scene and then you zoom out for the final render it's quite apparent.

Why do zoom in on objects to build shaders?  Because I'm often looking at a physical sample in my hand and can put it as close to my face as I want to see the detail, grain, how it reacts to light at different angles etc.  I'm rarely building shaders whilst looking at a finished building/interior from the perspective of my CGI camera as a reference.

2022-12-13, 13:49:14
Reply #26

Maybejensen

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Yeah microdetail is always problematic. Reduce filtering in either map (native or Corona, or bumpconverter node) and you get possible artifacts. Don't, and your detail is very much angle and resolution dependent. I don't like any filtering (I don't do animations though) but Bump/Normal can stop functioning without filtering. I've also been interested in Vray's elliptical filtering mode.

A solution that worked for me is to render quite high-res. You don't need to multiply your render-time in order to do so, down-sampling of noisier high-res files to lower resolution clears some of that noise. Also, denoised high-res file for most part looks better then undenoised lower-res file.

Possible solution for accurate detail vs animation smoothness is to use Devel/Debug menu override between these modes. There is no filtering option which can be default for stills.

I also don't use native max noise in bump, or much at all. I rather triplanar noise bitmap for more consistent result across resolution. The F-Storm is using its own noise map for good reason.
Very interesting. What do you consider high-res, 6k+?
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2022-12-17, 08:01:33
Reply #27

DPS

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+1 for not agreeing with the “if people aren’t complaining then it must be ok”.

In this instance I can at least see why it was done but sometimes we just assume it works.

Sometimes it’s a stupid thing like uvw randomisation doesn’t work with certain shader setups. You’ll spend an age dicking around and then eventual give up and fudge it and assume that it must be user error.
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2022-12-19, 08:09:14
Reply #28

danio1011

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+1 for not agreeing with the “if people aren’t complaining then it must be ok”.

In this instance I can at least see why it was done but sometimes we just assume it works.

Sometimes it’s a stupid thing like uvw randomisation doesn’t work with certain shader setups. You’ll spend an age dicking around and then eventual give up and fudge it and assume that it must be user error.

Yes, agreed. For better or for worse my assumption often is that the software is right and I am wrong.  Plus I am busy, so I can’t report a hypothetical issue.

For what it’s worth we always tell junior staff to be careful with Bump in Corona because it’s unpredictable and not that great.  Don’t get me wrong, we LOVE corona and all its features and it’s our primary engine.  But bump is not its highlight in our experience.  When I reduce blur it is better but sometimes kind of ‘rough.’  Anyway, would be cool to see this revisited by the dev team…maybe an alternate filtering method?

2022-12-19, 11:14:06
Reply #29

maru

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+1 for not agreeing with the “if people aren’t complaining then it must be ok”.

Yes, agreed. For better or for worse my assumption often is that the software is right and I am wrong.  Plus I am busy, so I can’t report a hypothetical issue.

Guys, can you please explain who and where exactly said "if people aren't complaining then it must be ok"?

Can you please carefully read my whole post here https://forum.corona-renderer.com/index.php?topic=38682.msg207109#msg207109
and here (especially the bold points at the end) https://forum.corona-renderer.com/index.php?topic=38682.msg207147#msg207147

I literally said that we are aware of this issue and would love to fix it. The only thing I do not agree with is calling bump mapping technique in Corona "so broken".


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