Underside of object is the expected colour and topside darker in perspective view

drawn a square and extruded it 0.5inch to represent a grassed area, however the grass colour given to the layer the object sits on is visible if I go below the solid and look upward, if I view it from above, as grass normally is viewed, its somewhat darker than the light green layer colour its assigned to.

why is the lighting in perspective window by default such that the underside of objects is lighter in colour ?


You didn’t include the file, so it’s hard to guess.
What happens if you use the DIR command and Flip the surface normal direction of that surface with the grass color on it?

It has nothing to do with projection type. Just some weird behavior of Ghosted display mode. It was “added” close to EOL (end of life) of R5 IIRC. It’s a very handy feature - don’t need to run Dir in Ghosted to verify face of the surface. Sadly, it’s not in R6 anymore and was probably an unintended bug in R5.

You might not notice that at first, 'cause the color difference is ever so slight. But when you start flipping surface face direction 'live", you’ll notice the difference. While doing it, you probably want your background be black too.