10hrs and still getting nothing decent :(

[nacho_grande]

Hi there.

I'm very new to Corona and I used it for a kitchen viz work today for the first time. All the material's Diffuse values are between 0,4-0,65. Eventhough the render time was very long (10hrs+), I got plenty of noise without any sharpness and clarity.

I have done some PP but I am not happy with the results. The raw exr files are also attached as a JPG file. (The raws were not seen this much dull and underexposed in VFB though)

What have I been doing wrong?

Here's the specs of my WS and the renders:

CPU: 2 x E5-2696 v2 2,50GHz (Turbocore:3.3Ghz) 48 thread.

[maru]

I would say it's not sharp because you are using DoF. :)
What render settings are you using?
Did you use portals?

You can also try this:
https://coronarenderer.freshdesk.com/support/solutions/articles/5000501983

[nacho_grande]

Yes I use DOF and eventually it blurs :) But even the focus point is not sharper as my client asked. :

I did not use portals. Does it make sense when using it with an HDRI enviroment?

Thanks for the link, I will dig it. ;)

My settings are below:

2000x910px
Progressive
GI/AA: 4
The rest are default

Corona Camera Mod:
F-Stop: 1,6
DOF: On

[Ludvik Koutny]

1, GI/AA of 4 is way too low for this kind of scene.

2, Did you disable shadow casting anywhere in the scene?

3, There is no way those white walls are under 0.65. Those walls literally glow and there are no contact shadows.

[maru]

I would try increasing gi/aa value to at least 8 or even reverting it to default value.
What GI solvers are you using? You should use path tracing + hd cache / uhd cache (depending on your version of Corona)
Portals - yes, it always makes sense when there are small window holes.

[nacho_grande]

Thanks guys. :)

My Corona version is Alpha v7.2

@Rawalanche: After the first render (file name Final 01), I discovered the Albedo pass. Then, I decreased all the diffuse values on the scene. Thta's why the first render looks even worst.

No I did not disable any shadow casting in the scene. However, I tweaked exposure, highlight comp and contrast values on the fly.

@maru: I used path tracing + hd cache. Next time I will put portals on the windows; plus, I will use thin glass.

[juang3d]

It feels like the focus of your dof is in the middle of the kitchen because even the books are a bit out of focus.

First of all I would try to use a GI/AA at default value as it's been said, in fact I would never go under 12/14 or over 22/24, these are already pretty extreme values IMHO

Second, portals, part of the noise feels like direct noise, this will be fixed with portals

Third, if you still don't get the desired crisp image, disable dof, enable Z pass and do the dof in post, it may not be as cool as doing it in render but it will save you some noise and bring you more control over it.

And fourth, if you still need more crispy look, then purse the image and reduce it after in post,this will give you more sharpening, you will be able to apply even a subtle sharpening effect in Photoshop before reducing it to it's desired size.

Cheers!

[nacho_grande]

@juang3d: Thank you very much for detailed critics. I will not touch the settings too much (Old habits inherited from Vray).

Should I decrease the diffuse value of the frosted glass to "0"? Can I get the milky look if I do that? Because those frosted panels are srill seen as red on albedo pass.

[nacho_grande]

I think 1.6 f-stop is also too much. Maybe 5.6 would work better.

[Fibonacci]

Last time when I got an noisy render after 8hr render time, than I put some softbox in the scene with 1000 lumen and 6000K and that helped a lot to cleaning the undirect light...Now 3-4hr is enought to render.

[romullus]

I think 1.6 f-stop is also too much. Maybe 5.6 would work better.

In interior photography it's usually in f8 - f16 range. Photographers would love to go even higher if not diffraction toll. In close up shots you can open aperture up to f2.8 - f4 when you want shallow dof. And f1.4 - f 2 range may work well for portraits, but not for interiors.

[nacho_grande]

@Fibonacci: I'll keep that in mind, just in case... Thanks.

@romullus: I should study my homework better, especially camera and lights of photography. I'll give a try to higher value dof for sure. Thanks.

[nacho_grande]

Dear friends. I have done everything you have said so far and this is what I got so far:

Render quality is apperantly increased. However, process time is still too LONG (5min per pass/10hrs render). I put portals at windows and adjust all the diffuse settings once again. There are still red areas as you can see on the Albedo pass. Eventhough all the frosted glass materials are the same, they react differently in the scene. Probably that depends on the angle and the light amount hits on the surface.

Albedo Pass + Raw Render + Post (PS Camera Raw Filter) are below:

1 HDR
2 x IES light (Added to the new version)
3 x Corona Light (Added to the new version)

Total: 11:13:08 !!!
HD Records: 217,446
HD success rate: 60,6
Passes total: 157
Rays/s total: 604,951
Rays/s actual: 51,316
Samples total: 8,209
Samples actual: 711
Rays/sample: 73,9


2300x1047px
Progressive
GI/AA: 64
LMS: 0,25
PT+HD
The rest are default

Corona Camera Mod:
F-Stop: 16
DOF: Off

[Nekrobul]

Very strange numbers for 2x core xeon.

I think there are some probles wtih materials that albeedo can not show.

Maybe you use too much multilayer blend materials.


And a little tip on postprocesing

[nacho_grande]

Very strange numbers for 2x core xeon.

I think there are some probles wtih materials that albeedo can not show.

Maybe you use too much multilayer blend materials.


And a little tip on postprocesing

Thank you for the heads up. Actually I have changed my settings to:

Portals on the windows (Co-planar to the outside wall poly and snapped to every corner and edge of the window space. Window frames and glasses are in front of them)

GI/AA: 32
LSM: 10
MSI: 4

I could get 175 passes in 5 hrs (CEVALLOS project 2500x1400 with no PP attached) The quality is pretty much acceptable. However, it still seems slow to me.

I used the very same settings for another scene and it took 10 hrs to 200 passes and the result was very noisy than the CEVALLOS project.

Maybe converted Vray and/or Max materials were the reason. :(

I really don't know what to do. My WS should render these scenes under 3-4hrs with a top notch quality.

The PP sample you have done is great indeed. You should prepare a tutorial about it, specific for Corona. ;)

Thanks again.