How life-like can 3D printing look?

say i wanted to print a marble column (don't worry about dimensions)....now obviously not a real marble column, but a column that looks exactly like marble without feeling like or being as strong as marble. In terms of smoothness and color detail, how well can 3d printing print something like that??? or would it be easier to paint the structure to look marble after printing?

or a tree....if the 3d model is extremely accurate to a real tree, could the printer print a tree with the exact detail of a real tree, making it look indistinguishable from real bark...and would it be easier to paint over the structure after or have the printer "color it" for me??

I think you could achieve some satisfying results. As for the marble, if you printed in ABS you could smooth it out with acetone and it would be shiny and smooth. Painting is also an option. You could also look into hydro-dipping for a real looking tree.

There are some DIY ways to hydro-dip with nail polish you can look into. It gives that streaky marble effect you are looking for.

What are you really trying to do? If the object is to produce a full-sized Greek temple surrounded by trees, you can simulate marble pretty will with concrete; concrete is also used for producing fake trees, like in Disneyland. If you want to make a small model of a temple, then sure, 3D printing can work. You can make a cheap monochrome print and paint it, or print it in full color if you want to spend more. Trees are more difficult to produce in miniature, since the leaves are going to be too thin to print well, but a bare tree isn't too hard. If you start with a good scan, you can get good bark detail; another way is to use displacement mapping.