Good morning.
I have a problem - I need to paint a bump texture onto my model, but as soon as I use brush, Blender freezes, and stops responding.
Bug.blend (2.3 MB)
Reproduce:
Please help.
My PC:
i5-4690K @3.5GHz
8GB RAM
GTX 970 3,5GB
On another project texture painting worked fine.
Works fine here; Ubuntu 16.04. Uses a lot of memory though. Maybe running out of free RAM is causing the freeze.
Yes, You are right! I run out of RAM. Do You know why though? I have previously painted 2048x2048 textures on this machine and it worked fine. Or is it due to polygon count?
Hi.
Here using Kubuntu Linux. Fill brush quickly fills my 16GB of RAM, it starts swap to disk and hangs my system. I did not know this could happen, the texture is not so big after all. I would like to know the explanation of why this happens.
The same here on OS X (16 GB of RAM), it does not freeze or hang the system but takes long time to fill.
EDIT:
BTW, I noticed just now that the Fill brush has the swap color button grayed out in the UI, how is that?
paolo
I have made a quick comment on IRC channel and was told to report the problem to be analyzed, just in case.
@Bednarov: Please report this to bug tracker:
https://developer.blender.org/
Top left, below “BF Blender” on “Report Bug” button. Fill in the required information and please share the problematic .blend file there (you can drag & drop from file explorer)
Thanks, will do that. Hopefully I will be able to finish my project soon 
Turned out, i had a sphere unwrapped over entire UV space - over all other islands - this caused blender to freak out.
Thanks everyone for help!
Oh I see. Anyway I’m not sure if it should generate so much use of RAM. You assume for some crazy reason you want to unwrap the sphere that way. Is that high usage of RAM in 60 overlapping faces covering 2048x2048 supposedly correct?
Sorry for asking in your thread, but I do not know much about UV mapping and I would like to know how it works in this case 
Blender don’t know on which part of the uv to paint, if one different island covers the other (i think).
I don’t think so, blender does know exactly where to paint, and it’s not unusual that every face of an object have to painted with the same image, that is that every face shares the same UV position, this should not slow down nor take so much RAM on painting.
paolo
EDIT: I didn’t read YAFU’s reply carefully enough, he already says the same thing, sorry.