clipka <ano### [at] anonymousorg> wrote:
> That total unresponsiveness is perfectly normal when starting a render 
> of an extremely large output image; POV-Ray needs to create a multi-GB 
> temporary file, and Windows insists on initializing this file right from 
> the start (rather than initializing only the blocks actually written to, 
> as Linux does), which may take several minutes.

In a sense POV-Ray has gone slightly backwards when talking about
rendering extremely large images.

Previous versions of POV-Ray had the idea that they would keep in memory
just a couple of rendered pixel rows (and AFAIK this only if you use
antialiasing), flushing the rendered pixels directly to the output image
file as soon as they are rendered. If you had displaying turned off, this
meant that you could render an almost arbitrarily large image (only
limited by the output image file format and memory addressing limitations)
without any problems because only a couple of pixel rows were kept in
memory at most at any given time. Rendering something like a 65536x65536
image shouldn't be a problem with an older version of POV-Ray.

In other words, the idea was like "render-and-forget" (for each pixel row.)
This was quite efficient for rendering very large images.

POV-Ray 3.7, however, has to keep all kinds of temporary files and
buffers for the whole image. You will quickly run out of memory and/or
disk space, and have all kinds of inefficiencies, when rendering very
large images.

-- 
                                                          - Warp

Post a reply to this message