I upgraded to the newest official version of Blender for Windows.
Now I can render a picture without a problem, then I render it again and it is a black image.
I have to exit Blender and open the project again to do another rendering. Any ideas on this problem?
Sometimes my renders windows show up black. I find if I move the window frame a bit, the render shows up in the window. Very odd behavior.
Still doesnāt work. I know what you are saying, but suddenly this problem is occuring.
you mean, if you click the RENDER button, a new window pops up with a picture in it, positioned as per the position buttons. Then you close that window (X) and click RENDER again, and then a new window pops up, but does not have a picture in it??? without clicking ANY other buttons?
Try setting the Render output to Image Editor. Scene/Output/Render display
Yes.
I click Render (or F12), either one. A good picture will render. Then if I do absolutely nothing. Nothing at all except to render the picture again, just for the sake of doing it, and no other reason ā¦ ā¦the picture is black.
I have narrowed the problem down to one specific Blender project. So something within that Blender project is corrupted.
Fortunately, I save my projects several times with numeric names. I have a few hundred āsavesā and I am in good shape. Nothing lost, but this weird problem is bugging me.
well, the good news is, the second render, even if it was rendered, wouldnāt look any different from the first;) so it doesnt matter anyway. So, donāt render twice. there; problem solved.
the bad news is, we have no idea what corrupted the file.:mad:
The problem is, I render frequently. When I adjust my lighting, the next rendering is black. So, the problem still exists. I may post the BLEND file for anyone to tinker with.
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Aha! Busted. you DID touch something. Adjusted the lighting. you know that lighting is clipped, eh? and that spots are directional? post your blend and tell us what you did and we will use our infiinite expertise to assist in figuring out what Blender is doing. Or report a bugā¦
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Too late. I already deleted it.
I have a backup that is recent, which is what I am using.
ā¦but wait! Even without adjusting anything (like the lighting) it happens. And I did check the lighting and the clipping. Anyhow. The file is now goneā¦ 
In Spinās defence, I get this occasionally though for me it usually works okay if I just render again. Itās never happened often enough, or repeatably enough, to worry about (OSX.3.9) but maybe there is a real problem there somewhere.
Some things to maybe try:
If, like me, you like to keep your camera and lighting on different layers to your various mesh objects, then maybe move them to common layers and see if the problem changes.
Have you tried F3 saving the image when it renders black then opening in editing software to see if the image data is cached properly but not displaying in the render window?
Iām sure there is. I know that there aināt two lines of software out there that dont have a bug in at least one of them. Frankly, Iām amazed that it works as reliably as it does, cross platform and all. I would suspect a video driver initialization bug, but thatās just a shot in the dark. If we could eliminate platforms, we might have been able to narrow it down (probably to an ATI card lol). I know how you love them, AndyD.
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i know. isnt that SO funny!!! I really had to laugh at that. And the poor schmoe at Nvidia who REALLY knew what he was doing was probably fired for being late on his project because he spent too much time making HIS driver really fastā¦while the ATI guy who didnt have a clue got promoted for being on-time and under budget with his, and got a Christmas bonus because of ATIās market shareā¦
Iām not thinking the OpenGL drivers would improve RENDER speed yet, would it? I know hardware rendering is available, but I didnāt think blender took advantage of it. The DISPLAY speed would increase with different drivers for SURE, but rendering?
im not a Blender internals guy, but I think that Blender calls on OpenGL driver routines to actually calculate what the render will/should look like. Once the ādisplayā is calculated, it is sent to the video to be physically displayed.
If we could eliminate platforms, we might have been able to narrow it down (probably to an ATI card lol). I know how you love them, AndyD.
Huh? What do I love? ATI cards? Hmmm, never had a video card problem that Iām aware of and I canāt remember what card I have. A Radeon I think - whatever that is. I really donāt know the first thing about video cards. Iām on a Mac and as far as Iām aware all the recommendations to turn on THIS and turn off THAT and tweak THE OTHER donāt apply to OSX. Maybe you got me confused with someone else - or just got me confused. Maybe you need to get your wife to get all those kids lined up and behaving so you can concentrate on what youāre doing :).