the werid below-ground color

sun is not available maybe but in luxrender(spectral) it is

Thanks for the suggestion, but this tracker is not for feature requests, see here for other options:
https://wiki.blender.org/index.php/Dev:Doc/Contact#Requesting_Features

Reduce your tile size in the render settings, should fix the issue.

There was no crash reports at that time for id 4101, but this is what was found during the error "illegal address" :

<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="nvlddmkm" /> 
<EventID Qualifiers="49322">13</EventID> 
<Level>2</Level> 
<Task>0</Task> 
<Keywords>0x80000000000000</Keywords> 
<TimeCreated SystemTime="2017-06-19T14:33:07.194255300Z" /> 
<EventRecordID>14416943</EventRecordID> 
<Channel>System</Channel> 
<Computer>Computer_i7</Computer> 
<Security /> 
</System>

• <EventData> <Data>\Device\UVMLiteProcess4</Data> <Data>Graphics Exception: ESR 0x524e48=0x1000e 0x524e50=0x4 0x524e44=0x13eff2 0x524e4c=0x7f</Data> <Binary>0000000002003000000000000D00AAC0000000000000000000000000000000000000000000000000</Binary> </EventData> </Event>

Can you check your windows event log for any reports of event ID 4101 around the time that blender crashes?

Here's the blender.log, I assume there's only the last part of the action (quit)...

Thanks, now we know issue is still in current code.

Ok, latest version 2.78 downloaded - results :

• Blender default scene
• Cyclic rendering
• GPU mode

--> render -> CUDA error : illegal address in cuCtxSynchronize(), line 1371 (render stops)

In T51696#440786, @Bastien Montagne (mont29) wrote:

@Tapani Korhonen (Tapu) Please always try the latest build from our buildbot.

Ok, this is the version what I'm using at the moment. It has been released in january 2017, I installed this version in april - it's the official version.

@Tapani Korhonen (Tapu) there is nothing more to inform, as said just download latest build from given link and test with it, this is basic task to do before reporting a bug (those daily builds reflect current master code, not as stable as official release, but will contain all fixes done since last release).

The Blender version is 2.78c and it's installed in the mid of april 2017. Please inform if there is a new version to be installed.

In the fluid domain settings, there's different Final Display and Viewport Display modes. If those match the result is the same.

@Tapani Korhonen (Tapu) Please always try the latest build from our buildbot.

Those are inducted errors, we need to know exact first CUDA error and know what cycles was doing right prior that error occurred.

This is the very first error when Cyclic rendering starts : "Cuda error : illegal address in cuCtxSynchronize()". I will be able to give more specific info, if you let me know how to do it.

Those are inducted errors, we need to know exact first CUDA error and know what cycles was doing right prior that error occurred.

This file is all what I got... there was only same "CUDA error : illegal cuda address in cuMemAlloc(&device_pointer, size)" repeating over and over again...
I do not have previous versions of Blender, as I told.

Please do full textfile log of everything printed by Blender to the console.
Also test if it ever worked in previous Blender version and whether it works with latest builds from buildbot.

Here's the file attached. There's only the Blender 2.78c which I've been using.

Please attach logs as text files, not as screenshots. Attached screenshots are lacking most crucial details since those are scrolled away.

Ok, started blender in --debug-cycles mode : image

Can you run Blender with --debug-cycles command line argument to make prints much more verbose to see where exactly things stuck. The resulting messages might help developers.

@Mai Lavelle (maiself) can this be closed?

In T49570#437697, @Dalai Felinto (dfelinto) wrote:

It should be fixed now, please test a night build and let me know if it still fails.

clearly not a bug, glad to hear you got it sorted though

Wow, I just realized what the problem was... I hadn't left-clicked my GPU in the prefs. menu... I had no idea I actually had to select it. Left clicking the name of my card literally fixed my device field being greyed out and now my GPU is being used.
Thanks for the help, though!

I wiped my drivers and reinstalled. No difference.
I also just noticed that the "Device:" field in my Render panel is greyed out. I can still set it to GPU compute, but the box is greyed out... Not sure what that's about.

Also check out Window->Show console, it might display some diagnostics information there

I updated my Nvidia drivers yesterday and it hasn't made an impact. I'm wondering if it might be old drivers conflicting. I think I read about someone having that problem.

Then it's definitely using the CPU , try a nightly build from https://builder.blender.org/download/ also be sure to install the latest drivers from nvidia, win10 is known to push shoddy drivers over windows update lately

As I said, it renders as many tiles as I have threads set in my Performance panel. Six in this case.

When it's rendering, do you have a single tile being rendered at the same time or multiple?

It should be fixed now, please test a night build and let me know if it still fails.

This is a limitation of the original implementation. This was refactored for 2.8, and it has the same render time in both cases. So closing this for now. Thanks for the report.

Stereo 3d will surely require some extra processing on the image, so technically it's not a bug but some possible optimizaiton.

For transparency working reliably it is needed to have face sorting of some sort, otherwise object draw order might be wrong and cause artifacts like that.

I think it's related:
Luxrender currently has option for custom ground color, really nice feature for larger scenes where there is need to model plane to hide sky leaking from ground. It works independently to albedo.

Thanks @Dalai Felinto (dfelinto). I posted that as a proposal, because I wasn't sure whether someone else noticed that behavior - realized later that something like this is bad practice. I'm sorry.