Iray renders black

samrkennedy

I am trying to render a cityscape with Iray, but the screen goes black.  It also goes black in the viewport when I switch to the Nvidia setting there.  I was just rendering a character in Iray and it was working fine.  Now it won't work with a city scene.  Why?

TheKD

Could be some geometry or light is blocking the camera.

mclaugh

How long has it been since you restarted Studio? There's a memory leak in DS that crops up when you render in Iray. Basically, DS doesn't clear all of the vram (or system ram) before starting a new render, and the leak is cumulative, so every render (even aborted renders) you run in a session holds onto a chunk of vram (unless you flush the cache), meaning there's the less vram is available for the next render. Once a scene exceeds the available vram, iray coughs up a black render.

Restarting DS is the surest way to completely flush the vram cache.

For me, toggling CPU rendering in the Render > Advanced tab (enabling if it's off, so CPG+GPU, or disabling if it's on, so GPU-only) usually frees up enough vram to render successfully. YMMV.

 

SimonJM

Just another thought - does the cityscape come with a skydome?  If so that could be acting as a light block

Fishtales

Check the scene tab and if there is a Skydome loaded delete it, they don't work in Iray without a bit of work. You can load the Skydome image into the Environment Map in the render settings if you want as that will work in Iray.