Rendering Issues: Black Squares

[savphili]

Hi all,

We are having some troubles at our office with black squares appearing in the "rendering final image" phase. We have never had this issue before and now all of a sudden we have been getting black squares appearing in the middle of our renders and shortly after sketchup crashes.

Does anyone know what might be causing this and how we can go about fixing it.

Thank you!
Steve

[mjm223]

Re: Rendering Issues: Black Squares

I get these whenever I use Distributed Rendering while rendering my scene. Usually the black squares mean that one of the slave computers (or even the main computer) has run into a glitch. On the DR Spawner screen of whichever computer ran into the glitch, it'll start saying something like "An Exception Occurred: Irradiance ..."

If you're using the Irradiance Map as one of you're rendering engines, you're going to have to reduce the quality of the image slightly.

If you go the the VRay Options and go to the Irradiance Map tab, adjust the Min/Max values. It started working for me once I set it to -4/-2 and it really didn't affect the quality of the rendering.

If that doesn't work, try lowering the number to -5/-3.

Hope this helps!

PS: I'm no expert on this, but I believe the min/max values represent the rendering quality of the Irradiance Map with 0/0 being the normal rendering quality. Any number you set that's greater than 0 will get you a higher quality rendering, but a longer rendering time. Any number you set that's less than 0 will reduce the quality, but speed up the rendering process. The difference between the min and max values (plus 1) represents the number of prepasses your rendering will take. It's best keep the number of prepasses between 2-4.

In terms of the quality of the final output, I personally don't notice much of a difference between a rendering with a min/max value of -4/-2 and one with a value 0/0. But I have noticed a slight improvement in quality if you kick it up to 4/6. The question is, can your computer render that without crashing? Mine has done it only once.

[savphili]

Re: Rendering Issues: Black Squares

I get these whenever I use Distributed Rendering while rendering my scene. Usually the black squares mean that one of the slave computers (or even the main computer) has run into a glitch. On the DR Spawner screen of whichever computer ran into the glitch, it'll start saying something like "An Exception Occurred: Irradiance ..."

If you're using the Irradiance Map as one of you're rendering engines, you're going to have to reduce the quality of the image slightly.

If you go the the VRay Options and go to the Irradiance Map tab, adjust the Min/Max values. It started working for me once I set it to -4/-2 and it really didn't affect the quality of the rendering.

If that doesn't work, try lowering the number to -5/-3.

Hope this helps!

PS: I'm no expert on this, but I believe the min/max values represent the rendering quality of the Irradiance Map with 0/0 being the normal rendering quality. Any number you set that's greater than 0 will get you a higher quality rendering, but a longer rendering time. Any number you set that's less than 0 will reduce the quality, but speed up the rendering process. The difference between the min and max values (plus 1) represents the number of prepasses your rendering will take. It's best keep the number of prepasses between 2-4.

In terms of the quality of the final output, I personally don't notice much of a difference between a rendering with a min/max value of -4/-2 and one with a value 0/0. But I have noticed a slight improvement in quality if you kick it up to 4/6. The question is, can your computer render that without crashing? Mine has done it only once.

Marcus, thank you for your input. I really appreciate your insight. We actually those numbers up (from -3,0 to -2,1) instead of going lower). We will definitely try your suggestions and I will keep you posted. Thanks!

[TqM]

Re: Rendering Issues: Black Squares

I get these sometimes when not running a DR, what I've found is it is related to how much ram I am assigning to my "Mem(ory) Limit" under system. I've cut it down to a conflict between my computer and the render where the render is taking up more ram than my computer has to offer and my computer in turn is reclaiming some of it for other vital processes, when it does this it is essentially deleting the previously mapped areas causing an error in the final rendering stage.

So as was suggested... lower the quality. Or the preferred option, get more ram (i need to do this soon).

What OS are you running out of curiosity?

[nongsaewong]

Re: Rendering Issues: Black Squares

I got this ploblem too. And I can't fix it.
I try to reduce the quality of the image (I use-5,-3 but it doesn't work).
Have any more suggestion for this ploblem.

thank

[mjm223]

Re: Rendering Issues: Black Squares

I got this ploblem too. And I can't fix it.
I try to reduce the quality of the image (I use-5,-3 but it doesn't work).
Have any more suggestion for this ploblem.

thank

How big is your final rendering? I once had to render a poster size image that was 6000x4000 pixels, and it didn't start working for me until I lowered the min/max values to -8/-6.

If you have a large image, keep lowering the quality until it renders properly.

Another thing you can do (it may be a little extra work, but it's helped me out) is save the light cache map and IR map. Assuming you're using the IR Map as your primary engine and the Light Cache as your secondary, start rendering your scene with both Light Cache and IR Map set on "Single Frame."

-If you start getting the black squares during one of the prepass phases, go to the VRay Options menu (without cancelling the render) and save the light cache map. Now cancel the render. Then, go back to the Light Cache tab in the VRay Options and change the setting from "Single Frame" to "From File" and load the light cache map that you had just saved. This will save your computer time while calculating the light cache and thus may free up some more RAM for your computer to render all the way this time.

-If you start getting the black squares during the final rendering phase, save both the light cache map (if you haven't already done so) and the IR Map. Then cancel the rendering. Before you restart the rendering, make sure both Light Cache and IR Map settings are set to "From File" and that both corresponding maps are uploaded. Now, when you hit render you'll go straight to the final rendering phase and you should have a better chance of completing the rendering.

-Finally, if you're still getting black squares in the final rendering phase even after doing those first two steps, allow it to finish rendering completely. Once it has finished rendering, save the image (this will be a backup image, just in case the next step backfires. Worst case scenario, you'd have to render two parts of the scene and paste them together in Photoshop). After you've saved the image, click the render button again, but DO NOT CLOSE THE FRAME BUFFER! Keep it open! Once it starts rendering again, you'll notice that it'll go straight to the final rendering phase and render right over the image that's on the frame buffer. On the frame buffer screen, look for a button that has a blue square with a tiny mouse cursor over it. That's the "Follow Mouse Cursor" button. Click that and the rendering cores will follow your mouse. Now simply roll your mouse over the black squares on the frame buffer. Do this until you've got all the black squares taken care of. Save the image and you're done!

I hope this helps!