I've been getting generally good prints with the exception of little blob artifacts here and there on my vertical surfaces. On a printed pyramid the x axis faces showed the blobs randomly across the face but on the y axis sides the blobs were centralized along the middle from bottom to top. It turns out that "Random" seam position is not so random on the y axis. I switched my settings to "External Perimeters First" and viola, smooth surfaces. It turns out that the blobs were caused when the nozzle jumped from the inner perimeter to the second and outer perimeter. I wish my camera got better close ups so that you could see the difference. It appears that "random" seam position is completely different when starting with the outer perimeter first. So, to summarize, check the box to "Outer Perimeter First" in Slic3r under "Layers and Perimeters" tab.

Y axis side with Default inner perimeter first setting.


Same setting on x axis side


With outer perimeter first setting. Sides are smooth except for a line of blobs about 1/8" off of the left corner. Same on all four corners.


Well hell, it obviously hasn't completely eliminated the problem. I wonder if "Aligned Seams" would be the way to go. I'll try another print with that setting.

Ok, so "Aligned" seams start in the same corner every time. So, "Outer Perimeters First" with "Aligned" seam position seems to be the ticket. At least on non-freeform shapes.

Overhangs are hard to print when using "Outer Perimeter First"

Excellent point. After this last print it is obvious that "Inner" first has only a bit better result on surface finish. Only "Aligned" seam position kept the artifacts from appearing on my surfaces. I apologize for wasting your time reading a post that should have been thoroughly investigated before hand.