Problem with very BIG pictures

[TOBTHREEDEE]

I used a material and the picture looks great.
Now i rendered a big picture over 3000x???? pixel
and there is now my problem. I see this little
dark spots. What can I do to get a clean picture
without a very huge rendertime?

The dark spots are the parts of the object where
its geting darker (shadow area starts)

Some Vray settings:
-adaptive subdivision, minrate 0, maxrate 2
-gi, irradiance map or direct computation (there
is no big diffrence between my irr.map setting and
the direct setting
-qmc Sampler, Amount 0,85 and noise threshold 0,005

there are good results if i switch the noise threshold
too zero or the amount too 1 but the rendertime is
so ugly.


THANKS

[cuototo]

Hi Tob,

Try this:

Adaptative subdivision: -1 2

Irradiance map:
Min rate: -3 Max rate: 0
Clr Thresh: 0.3 HSph subdivs: 50
Nrm Thresh: 0.3 Interp samples: 20
Dist Thresh: 0.1

Also change the AA filter to Cook Variable 2.5 (works better for me)

Tell me if it works

[TOBTHREEDEE]

wow, very great rendertime.
sorry, the same problem.

It also doesn´t matter if the subdiv. is 0 or 100 (there is always the same problem)

I found out, that this must depend on the HDRI where I´m using in the environment setting. Without the HDRI, there aren´t any dark spots. But I need the HDRI.

so, if you have more ideas....

[s7en]

Got a couple of ideas you could try:

1) Try increasing the Irradiance map Interp samples to something like 50 or even 100. This should blur the darkspots, but it may soften your lighting too much.

2) Try editing the HDRI map you're using. Use a tool like HDR Shop - available from here http://www.debevec.org/HDRShop/ and blur and/or shrink the HDRI map. Using a smaller, blurrier version of an HDRI for lighting often produces a smoother looking result. You'd still want to use the original, full size, nonblurred HDRI if you're also using the hdri image as a reflection map though. i.e. stick the blurred one in the GI enviroment map slot, and the orginal unblurred one in the reflection map slot.

give 'em a go.

sven

[cuototo]

Are you also using any other lights?

It may happen that the quality of the HDR affects the quality of the shadows. In adition, illuminating with HDR is slower than using just the skylight.

Why do you need the HDR? If it is just for reflection, then you could disable the map in illumination. Could you post a biger area of the render? I don´t understand what it is and what is the situation in the scene.

Also try to view it with a zoom of 1:1.

hope it helps

[RErender]

Blur the HDRI and/or use a lower res version for the lighting.

[TOBTHREEDEE]

I tryed diffrent values of the Irradiance map Interp samples (like 50 or 100).
The best result is with the amount of 1 and noise threshold with zero in the QMC Sampler. But, the rendertime is so loooonnnnngggggg.

It´s really a problem with the HDRI which I use. I have no problems with other HDRIs. Hmm, I want or I have to use this one! In other pictures it will be ok, but not here.

@ s7en: I use a material wich combine a sharp and a blurry material, so a smaller, blurrier version doesn´t fix... now i´m looking for a better version of my HDRI (I tested a smaller one also)