rendering problem with huge images

i try to render a 12000x8800 pixel image with cycles in blender 2.71. i render with the cpu and have 8gb of ram.

the render takes about 5 hours and everythings seems to be fine. but after the last few tiles are done the image vanishes and i can’t save it. :confused: what could be the reason for this?

…and does blender save some kind of backup of the last render i could find? :slight_smile:

Render in pieces then stitch in the compositor. IIRC there is a memory issue with big render sizes.

Could be more to do with the compositor / saving the file out rather than rendering the file itself.

The main problem is ram. Youre best bet is to close all other programs on your machine to make sure blender has access to all the ram… if that fails… border render with crop and stitch in a program like gimp / photoshop.

(we have rendered up to 30k images before in blender… it just chews up a lot of ram)

One trick I’ve discovered is to “Render border” select using the “ctrl-B” option, and on the render properties, check render border size, but UNCHECK crop to selection. Then, save each render section into a separate PNG file (or any other format that will save the alpha channel). A little overlapping of areas is fine, because when you’re done, all you have to do is stack all the images using Blender, GIMP, Photoshop, or whatever image editing software you like that takes advantage of layers.

This works up to a certain size… still fails somewhat if you go too large / use the compositor… As the entire image has ot be held in ram to save it out.

Maybe Monster Tile render addon is still working.