Hello fellow ZBrushers,
I want to share a post processing procedure I came up with for cleaning up 3D print build lines which also provides a nice paint ready finish for acrylic paint. I built an FDM machine last spring in order to prototype my models and get a handle on 3D printing before investing in a higher resolution machine or having prints done by a printing bureau. I printed this model at 100 microns, it took about 18 hours and is 5 1/2 inches tall.
Borrowing from my old-school paint on canvas days; I grabbed a couple of palette knives and a jar of modeling paste. If your not familiar, modeling paste is a mixture of acrylic base with marble dust. I apply it with the palette knife much like a dry wall installer applies joint compound to sheet rock. I scrape off any excess while it is still not quite dry. If done carefully this fills the gaps between layers while still retaining detail.
Modeling paste is easily sanded and non toxic so you can achieve a smooth surface with not a lot of effort. It is also good for filling in problem areas on prints too. In the image below you can see where my hot end clogged (a story for another time) but suffice it to say I was a able to stop the print clear the clog and finish printing. However it left a sizable gap and modeling paste came to the rescue to fill in the space. You can see the difference in the before and after images below. It could use some more cleaning up but I think it gets the idea across reasonably well and the color of the modeling paste is brighter than the PLA filament I used.
Give it a try, I hope you find this process useful.
Happy ZBrushing!
Dave