Can someone explain this to me?

Drogo Nazhur

Some scenes, rooms, etc.; render perfectly. The skin texture is perfect and looks almost like a real photograph. AND, I don't need to do any work with lighting, etc. Other scenes / rooms render horribly. Even if I use te exact same character in the exact same pose, the character comes out very grainy. Even if I try to adjust the light, they still come out looking awful.

Why?

And is there a way to tell which packages will do what before buying them?

Richard Haseltine

Assuming this is Iray in Daz Studio, lighting - the lights you are using, or the way light enters the room, or the reflectivity of the surfaces (shiny = more bounces = longer to render each iteration), or the structure of the room (more awkward spaces relying on indirect light) mean that the scene is taking longer to converge, and is timing out before it reaches such a high level of convergence as the smooth scene. You can adjust the maximum time (in seconds) in the Progressive group in Render Settings, and if the issues is too many bounces you can adjust the maximum number (the path length) in the Optimisation group. Adding more lights (such as low opacity emitting planes, using the Ghost Lightss et or making your own) and then compensating with the Tone Mapping settings should help with most of the issues.