The bar showing progress is still zero percent.

karikari_twitter-1

Does anyone know why the rendering is progressing but the progress bar is still at 0%?

Sevrin

Convergence percentage seems to be based on all light sources.  If you have weak light sources in the scene, they won't affect the look of the final render, but individually would provide a poor quality image.  That's what that percentage is based on.

In the end, if the render looks acceptable for its intended purpose, you can hit "Cancel" to finish and you'll be fine.

karikari_twitter-1

So you're saying that if you have multiple light sources, you're not converging them and you're just not making any progress, but you're actually getting closer to completion?

Sevrin

karikari_twitter-1 said:

So you're saying that if you have multiple light sources, you're not converging them and you're just not making any progress, but you're actually getting closer to completion?

Not multiple light sources.  Weak light sources.  If you have multiple strong direct light sources, your image will converge quickly, and the progress bar will reflect that.  Some scenes will have a lot of small emissives, serving as indicator lights, etc, and for all Iray knows, they're supposed to provide significant illumation.  They're not, so you need to use judgment.  Iray can only estimate when an image will be satisfactorily rendered based on the criteria set in Progressive Rendering.  it can't decide it.  Some people turn off quality altogether and don't bother with the progress bar, at all.

Another thing that will confuse Iray is if there's a lot of reflected light, especially in enclosed spaces where rays have no way of escaping.

karikari_twitter-1

I see! I understood it very well. Thank you for telling me.