Corona Renderer Forum

Corona Renderer for Cinema 4D => Corona Renderer for Cinema 4D - general => Topic started by: BigAl3D on 2019-02-12, 20:35:43

Title: Dancing Fireflies (I Think)
Post by: BigAl3D on 2019-02-12, 20:35:43
So here's a short clip of a scene I just rendered. Overall, I'm very happy with the results, even with my limited knowledge of Corona. In this section of the animation, we're seeing a lot of movement in the chrome bars along the sides of the screen. There is no movement at all at this point in the scene. There are a few lights around as you can see in the screen shot. I don't believe is the standard idea of dancing noise, since there are many areas in this shot that are perfect for dancing noise yet there is none. I tried rendering as high as 60 passes with and without denoising. Still they dance. Follow the link below to see the clip. Yes, I did also try the Flicker Free option as well with same results, which seems to confirm to me that is't not really noise, but maybe fireflies. Not sure how to tackle them. I will say in this instance, I can just use a still image when it's not moving, but I'm sure I will need to move the camera at some point. I'm also uploaded the scene for you to examine. Thanks for your help.

https://bit.ly/2TLarbx
Title: Re: Dancing Fireflies (I Think)
Post by: TomG on 2019-02-12, 20:42:47
I get a "sorry we couldn't find that page" from the Vimeo link.
Title: Re: Dancing Fireflies (I Think)
Post by: BigAl3D on 2019-02-12, 21:54:02
Hmmm. I tried another Vimeo link and it comes up as "Not a valid Vimeo link." If I try it in a browser I'm not logged into, it works.

I posted a Bitly link. Try that. Thanks.
Title: Re: Dancing Fireflies (I Think)
Post by: TomG on 2019-02-12, 22:00:28
That worked. Best bet would be to upload the scene. Seems only to happen in the right and left structures, so I wonder if there isn't some strange geometry there, overlapping faces or something (though that seems unlikely, but never hurts to ask). Does look like the UHD Cache (have you tried baking it to see if that changes the result, or use Path Tracing instead? That would narrow down possible causes).

https://help.c4d.corona-renderer.com/support/solutions/articles/12000033461-how-to-report-issues- if you want to upload the scene.
Title: Re: Dancing Fireflies (I Think)
Post by: BigAl3D on 2019-02-12, 22:04:48
Good idea to check the geometry and the Path Tracing. How would baking help this scenario? There is also some larger areas when the car shows up rotating that seem to change brightness, but I forgot to enable the Flicker Free function so not sure that would fix the problem there.

I did upload a scene already and linked to this thread. :-)
Title: Re: Dancing Fireflies (I Think)
Post by: TomG on 2019-02-12, 22:10:19
Baking means that the UHD Cache is only calculated once and can't change from frame to frame (so can't flicker - if it does still flicker with a baked UHD or Path Tracing, it can't be the UHD Cache causing the issue :) ). And ty for uploading!
Title: Re: Dancing Fireflies (I Think)
Post by: BigAl3D on 2019-02-12, 22:13:23
Also, the most visible jumpy parts are only on the bright reflections/highlights. I keep getting errors when I try to combine my image sequence for the entire :30 sec. clip. I'll try again.
Title: Re: Dancing Fireflies (I Think)
Post by: TomG on 2019-02-13, 14:38:49
I have missing plugins on load, with these being:
CV-ArtSmart Pathinfo
CV-ArtSmart Object

When I render, I get a very different result from you, not sure if this is due to the missing plugins or something else (see attached). Unfortunately that means I can't try to duplicate your results at the moment :(
Title: Re: Dancing Fireflies (I Think)
Post by: BigAl3D on 2019-02-13, 17:13:42
The Artsmart plugin is free from Cineversity when you set up even a free account. I'll PM you a link. But, that plugin is only used for the Illustrator logo later in the scene. It allows you to import any vector, add depth, space out the layers, even import the colors. Anyway, that wouldn't have anything to do with the lighting I see in your test. That doesn't make sense.

Seems like... wait. I got it. I used an IES file for the light objects. It lives in the Visualize.lib4d, but you should have that if you have Studio. Maybe you didn't install the Content Browser libraries? Just go to update and if you don't have them already, you'll see them listed and just click update. That particular library is around 3.5 GB. I don't know how to extract that one file from the library.

Worst case, you can turn off the IES function.
Title: Re: Dancing Fireflies (I Think)
Post by: beanzvision on 2019-02-13, 17:21:22
I think I have their plugins somewhere, I'll have a search and try and test out the scene. ;)
Title: Re: Dancing Fireflies (I Think)
Post by: TomG on 2019-02-13, 17:31:38
I turned off the IES, but had to raise the light intensities to around 40 to start to get something close :) Not sure I can find the IES stuff in the content browser (as it's a beta / test  / developer version of C4D that I have on my machine, not a regular install). Going to ignore the plugins since they are related to something specific that shouldn't have a bearing here. Anyway, will see what comes out with no plugin, no IES, brighter lights.

BTW, what happens if you render without the IES, just out of interest?
Title: Re: Dancing Fireflies (I Think)
Post by: BigAl3D on 2019-02-13, 17:57:28
Ah, identical to the image you posted. Good call. I understand I have a lot to learn about Corona in order to get the best out of it, but I'll keep at it.
Thanks for taking a look.
Title: Re: Dancing Fireflies (I Think)
Post by: TomG on 2019-02-13, 18:11:25
Just in case there is confusion - in the image I posted, everything was as received and too dark. I have since turned off IES and raised brightness, and now get an image much like yours, and can see the effect. It isn't the UHD Cache as setting things to PT doesn't resolve it. It isn't the expression on the lights, removing that doesn't resolve it. So, still looking :)
Title: Re: Dancing Fireflies (I Think)
Post by: TomG on 2019-02-13, 18:25:15
Either the camera or the screen is actually moving. I deleted animation keyframes for both, and the effect disappeared. I haven't tested each individually. It looked like there was one keyframe when they should start moving, but no keyframes before that, so it could be there was some "ease in" effect that means it is moving before the first keyframe. You might try either setting another keyframe one frame prior to before they move (just copy the keyframe at where they start moving, so that it stores the same data twice), or copying the keyframe before they start moving at frame 0 (or both).
Title: Re: Dancing Fireflies (I Think)
Post by: BigAl3D on 2019-02-13, 20:47:48
Yes, now I see the screen group comes down and rotates, but it only spins to -0.4° then SLOWLY rotates to 0.0° at frame 339. My mistake. If that will solve this case, perfect. BUT, what if I WANT a slow camera move. Corona shouldn't produce this much dancing right, otherwise that is a major limitation. You mentioned baking earlier. So if I render without the beauty pass and save the UHD Cache, is this what you mean? If yes, then how to handle the first section where I animate that back light from 0 — 40?
Title: Re: Dancing Fireflies (I Think)
Post by: TomG on 2019-02-13, 20:57:52
Well, baking won't resolve this one, as even using PT doesn't change it. This is all reflection as far as I can see, so no render settings to change that.

I doubt anything would ever be moving THIS slowly in a final animation though :) And if it is the results will depend very much on what is going on - this is actually all reflectivity, as far as I can see, and is related to the angles of the lights in this particular scene and how much they change with the small movements; could also be related to bloom and glare too (either making it worse here, or it could also be that careful use of bloom and glare could soften that out). It may also be related to the super high Fresnel IOR. Potentially, some softening of the reflections with Glossiness might help. Could also check into Blur/Sharpen as well. So, lots of things to try to soften out how those reflections are changing from frame to frame, should you find yourself looking for something moving this slowly in the future!
Title: Re: Dancing Fireflies (I Think)
Post by: BigAl3D on 2019-02-14, 01:28:48
Hey Tom, if you visit my Vimeo link again, I've updated it to :30 sec so you can see the rest of the animation. When the vehicle slowly spins, you can see larger areas that change brightness, mostly along the bottom edge of the car. Remember, I did not render with Flicker Free yet. Will this setting eliminate this "flicker?"

Thanks.
Title: Re: Dancing Fireflies (I Think)
Post by: TomG on 2019-02-14, 13:30:16
Hard to tell, those do look like they could be UHD Cache issues but can't say for sure. It would certainly be the first thing to try (assuming the UHD Cache is being used, of course!)