easy rendering for Rhino in Windows
Anyone know why I would get lines in the shadows on a 1.5hour rendering for an 8.5 x 11" @ 300dpi very simple render using just the default NXT lighting? Was expecting to have just a nice shadow fade without the lines. I think I let it render long enough.
Those look more like different levels of shadows caused by the imaginary multiple lights.
As far as I can tell, when you hit "Render" without explicitly having added your own lighting (point light, spot light, etc) the default lighting comes from multiple overhead sources.
Easiest way to see this is just create a vertical cylindrical object (pole, tin can, etc) and hit "Render". You'll get multiple shadows at the base. Where shadows overlap, the spot is darker.
It's this very same idea in your rendered pic above.
To override their lights, add any light (point light, spotlight, etc) to your 3D scene and the multi-shadow thing goes away.... that is, until you add a 2nd, 3rd, 4th light in different overhead locations.
If it's resolved pretty well then here are some possibilities. (It's actually hard to say how resolved the thing is since you're rendering at such a high-res.) How many passes?
The default lighting is an hdr of a eucalyptus grove. The trees do cast some shadows so you might be experiencing some of that. Try another hdr (or perhaps, a cloudy sky) for something more uniform.
Another possibility is an artifact called "mach banding"-- a consequence of 24 bit color space. Not much to be done if this is the case.