I have many spotlights in my scene and half of them appear in the Arnold RenderView. I tried duplicating the working lights and creating them from scratch, but nothing I add affects the render anymore! What could be the issue?
Isolate Selected is on?
The light intensity isn't high enough?
It turns out I had to restart my computer and Maya. The lights are working but for some reason there was a time Arnold RenderView stopped acknowledging new lights in the scene.
When that happens (no more dynamic scene updates) you don't need to restart maya or your machine.. just shot a straight render with for example render->render current frame. the dyn scene will be flushed and when restarting arnoldrenderview you'll get correctly new scene updates.