Suddenly batch render prob caused by "Use Background"

#1

Using Maya 2015 ext 1:
Not sure what suddenly caused this, or if having to restart the machine after it hung earlier today might have done something, but after no problems rendering this scene, now when I try to run batch render, it starts, goes a few seconds, and then reports “rendering completed”, but nothing has actually rendered. Sometimes the Render Log simply has “DB 0.7 79 // Maya exited with a status 1”, and a few times it has reported “attempt to access null DB tag”–but it doesn’t seem to report the DB tag issue every time. So…

I’ve figured out that it has to do with a plane that I am using simply to catch shadows with the ‘Use background’ shader applied. If I switch the material from “Use Background” to a default Lambert, the render problem goes away. If I turn off visibility on the plane outright, or uncheck “Primary Visibility” in Render Stats, it keeps rendering just as it should. If I delete the “Use Background” shader so the plane has no material applied at all, it renders fine.

But with the “Use Background” shader in place, if I simply recheck “Primary Visibility” and try to batch render, it starts and almost immediately says “Rendering Completed” and stops. I even tried deleting the background shader from Hyperview and adding in a new copy and reapplying that to the plane. Same problem.

Again, this was working fine earlier today, and haven’t knowingly done anything new with this plane or done anything to the Use Background shader, so I don’t know what might have suddenly caused this problem, let alone how to fix it.

Anyone know what might cause this bizarre problem and how to resolve it? Would appreciate any suggestions.
JT

#2

A quick correction…I must have jumped the gun because it appears that simply unchecking “Primary Visibility” does not stop the batch render problem, as I thought it did, if “Use Background” is applied. So it seems to be something about having that background shader that’s the culprit…

But if I uncheck “Visiblity” in the Display options, so the plane is not rendered, then I can have everything else in the scene render just fine.

#3

Ah been so long since I saw the Exit 1. And the render log sounds pretty useless as usual as well from the sound of it. :frowning:

#4

I’m going to end this post myself by explaining what I think the problem was, or at least what I’ve been able to deduce about it that caused or causes this Mental Ray crashing problem. To hunt down the culprit, I began by exporting each object from the problem scene, then creating a completely new scene and importing the separate objects/elements back in, one at a time, to see if I could find at what point it would crash. I’d gone so far as to remove every Autodesk item from my pc, then reinstall Maya 2015 Ext 1 and go up to SP6, with Mental Ray for SP 6…but as it was, it would still crash (though with a few more clear error messages :slight_smile:

What I realized was that this scene was originally created in Maya 2014, with some paint effects-to-polygon trees and grass. When I set the scene up new in Maya 2015, used Color Management, and created a plane with “Use Background” applied, Maya was fine and Mental Ray rendered as expected. I then imported the plane created previously with the “Use Background” shader applied, and that didn’t crash it either…so I no longer presumed it had to do solely with the “Use Background” shader. I’m convinced now that it wasn’t that.
Then I tried importing a grass object originally created in Maya 2014…

However, I realized two things:
a) I’d already imported a set of lights, with a Physical Sun and Sky light, which was part of the earlier scene created in Maya 2014.
b) I was importing paint effects grass converted to polygons made in Maya 2014 because I wanted the look and settings I’d already created.

For some reason, importing just the grass seemed to cause Mental Ray to choke (red error in the status line), and halt the Renderview render. Even worse, if I tried to do a test render again, it would freeze Maya completely (not responding) and I’d have to kill it in Task Manager just to get out.
Once I recreated the Paint Effects grass and then converted it to polygons in the new Maya 2015 scene…it rendered fine with no errors!

One tree also originally created in Maya 2014 and imported into 2015 gave me a Color Management ‘color space’ error AND would crash like the grass did. There was something in an image texture that wasn’t in the color space I was using in 2015. I didn’t know how to fix it so I simply recreated the trees by copying the Paint Effect settings and painting them and converting to polygons all in the new 2015 scene. That problem seems to have gone now too, though I don’t think it was the color space error causing my crash/freeze problems.

As mentioned above in a)…I eventually realized that importing a previous ‘sunDirection’ light that already had miaphysicalsky and myaphysical sun did not automatically set up a Physical Sun Sky in the Render Settings “Indirect Lighting” tab. I thought that might work, and had tried to ‘Create’ another on in the new scene and then delete the new sunDirection light that was created and keeping my original imported one, hoping it might work (newbie attempt, admittedly.) After reinstalling Maya 2015 up to SP6, I now got an error when I attempted to create a Physical Sun Sky in the scene that already had my imported one, and I deduced from online searching that there may be a conflict. So I deleted the imported one and just recreated the Physical Sun and Sky from scratch within the new scene–and no more errors. So, maybe Mental Ray was having some issue with my imported light and mia_xxx settings all along, but at least I won’t do that again.

It seems to me, at least it’s my conclusion now, that Maya and Mental Ray 2015 Ext 1, or a combination of things, suddenly developed a big problem that I honestly believe came with the plant and tree objects I originally created in a Maya 2014 scene. It was working for a while, then a few days ago it would halt all rendering, and if I tried it twice it would crash Maya 2015 to the point of having to kill the process to restarting.
Perhaps it’s not inherently a Maya 2015 or Mental Ray problem, but I don’t know why the same Paint Effects plants that are rendering in 2014 with no problem would cause 2015 to crash. That said, I’ll just have to run 2014 for the 2014 scenes, and if paint effects are required then I’ll recreate them in the 2015 scenes before I try to render with Mental Ray. At least I’m working again after two days down trying to get this scene rendering again.

Maybe this will help someone…it’s cathartic for me.

#5

One last hiccup…after all the above, I’ve resolved that it is a plane that I was importing that seems to have caused Mental Ray to die. If I turn off ‘visibility’ on that plane…the scene will render everything else. I’ll continuing my hunt for a solution in another post so this one can end.

#6

Hey!

Did you discover the solution for that problem?

I’m trying to batch render a scene with Use Background Shader with Mental Ray on Maya 2016 but as soon it starts rendering, it stops right away and says that the rendering is completed.
I checked the render log for more info and I keep getting this error:
“fatal 041008: attempt to access null DB tag”

if I replace the Use Background Shader material on scene with the default Lambert I can render normally… I’ve been trying to exclude potencial issues that could have been causing this problem, but I’m certain the Use Background Shader is the issue (or something related to it and/or its relation with Mental Ray).

Thanks!