Render is black for a while before rendering

[Bagleyalex80]

Before I render a scene i always get a black screen for a minute or for even longer  before the image starts to render and my CPU is pretty powerful and it renders the image quickly but before hand the render is just black for awhile even though it says its rendering the image. it does this no matter what settings the render is set too low or quite high, wonder what could be causing this.

[hamsterHamster]

Does it happen so long also in a basic scene setup, like 1 sphere + 1 light? Is it just Arnold taking so long, or Maya render is also laggy?

[Bagleyalex80]

with one sphere and one light it is the normal speed, whats causing the render to do that, i use a lot of EXR texture maps if that also could be part of the problem which it probably could be take alot lot longer to load maybe. What could i do to stop that long back screen before the render from happening

[hamsterHamster · Accepted solution]

The black screen is while Maya and renderer reads and expands data for rendering. Once you have EXRs which are large files (especially when zipped option), then it takes time to read+extract+convert them to renderer's dataset. As for Arnold, you can speed this up by converting texture files to .tx format. Another contributor to the delay might be advanced features, like GI/AO/MB/etc which are calculated before you ever see the first pixels, some are single-threaded therefore slow. Some of this also can be sped up by pre-baking and -caching data.. depends on the renderer of your choice, therefore reconsider the need for each. And, usually, it is slowest for the first frame, less noticeable when batch-rendering sequences.

If you launch a batch render within Maya then you can see timestamped processes in Output Window, or when the command line render (faster), then in the console.