I started working with nodes today and blender started crashing.
Here is the work flow for recreating the bug.
Go to video copilot and download the zoom earth project files.
We will be using 07.jpg and earthStill.png to recreate the crash.
Open blender and setup the nodes like in the pitcure. I suggest using the image files from videocopilot to recreate the crash. While I am not sure if it is related specifically to those images, I have not tested the crash with other images. But, from a programmers point of view, I offer the sure fire way to recreate the crash.
To make blender crash simply set the X scale to 5 (look no crash), then set the Y scale to 5 (boom blender crashes).
Overall I have been experiencing a lot of crashing with blender 2.45. I hope someone who is working on the nodes code sees this post and implements a fix. It is a shame to see so many bugs creep in as blender grows stronger but if it continues, it will be no more stable than 3DSMax.
I hope others can verify this bug. It could, very well be a video driver issue.
I am running:
AMD @ 1.97Mhz
1GB Ram
Windows XP SP2
nVidia 6200 Forceware 94.24.
That is why I posted the URL to the images. If you actually pull down the images and try what I suggested it will crash blender. It may be a bug related to the dimensions of the images, and or their format. I don’t know. But being able to reproduce the bug is the most important thing. If it is a dimension issue or related to file type or size it is still a bug and should be fixed.
Also, the mixNode does not do what the alphaOver node does. To Illustrate this, I have attached another image. As you can see in the image I want my planet earth over a red background, but the mixNode can not do this. It makes my planet all white and pales out the red. It should be a solid red field with crisp earth image on top.
Perhaps you can post a node setup that shows it working correctly?
I did a little more investigating on the crash bug. The earthStill.png image is 2400x2400 so when I set it to scale by 5 in the X and Y direction memory allocation went out the roof. So blender ran out of memory and crashed. It is bad programming to blindly allocate memory assuming there is enough. As more and more people look towards blender’s compositing section as an alternative to After Effects, FCP and so on, it will be put to the test. And in my simple test, it could not even scale a single large image without crashing.
So I went the other direction. and scaled the image down instead of up. To my surprise, a flaw showed up in the mix node.
If you look at the attached node layout you will see that even though I did not scale the red background color, the mix node still scaled it anyway! I just want a small earth over a red field.
I also suspect that the Composite and Preview nodes do not display correctly on my system. Notice how I attached a value node to the alpha of the composite node. Even though the image shows a value of zero, I also tried a value of 1. This had no effect on the final render. I should have a value of 1 everywhere there is a pixel and value of 0 where there are no pixels. When I rendered my image and dragged the mouse around the window render all my alpha values were 0. If the alpha input works as I imagine it was intended, I should be able to attach a value of 1.0 and force the composite node to display a solid background. No matter what I do, the composite node viewer is always allowing me to see through it implying that the result is somehow transparent when it is not.
Here is another oddity of the compositing nodes system.
I finally got the viewer to display a solid RED background by forcing an alpha value using the seperate and combine RGB nodes. It looks like the alphaOver node does not scale it’s counterpart like the mix node does. But if you look at the attached image you will see that while the alphaOver node can stack two images, it can not stack a RGB color with an image. This seems like a bug to me because the RGB color node presents itself as an image to the compositing system. You may think, yeah, but you are forcing the alpha so no mixing can occur, but that is not the case, I can scrub the forced alpha value on the combine RGB and all that happens is the solid red fades to a translucent red (as it should). At a forced value of 0.5 I should at least get a half-mix and my planet should appear.
I think there may be an alpha problem through out the entire compositing system. At least I can say the nodes do not work consistantly and this is a problem.
The mix node uses the size of the image in the top socket, scaling the bottom to match. I haven’t even seen that RGB node you’re using (I use 2.44) but that node is more than likely a phantom like the texture input node (probably zero pixels X zero pixels). I don’t see what purpose it could serve that isn’t adequately served by a mix node. Maybe that’s why I haven’t seen it.
It seems to me that you’re wanting to generate images from the compositor. I’d like that too but it isn’t happening for now. You can use generated images in the compositor via the uv/image editor window’s header Add>New>Image, set the image dimensions in the popup window, then press enter. Go back to the compositor and Add>Input>Image then select the image you just created in the uv/image editor. These are procedurally generated images and addd almost no additional file size reggardless of the images dimensions…just like procedural textures and they’ll reapear in Blender each time you open the file without having to save the image to disk or pack it in the .blend file. Multiplying that image’s alpha channel by an RGB color via a mix node should give you the result you’re looking for. Gnderated images come in with alpha 1.0.
BTW, a Set alpha node would have been much simpler and efficient in that setup.
Atom, good point. please pack that blend file and submit as bug report, so the devs can trap that exception and give a nice little popup instead of a crash.All circumstances of a hard crash should be reported.
