Compare:
This portrait was drawn using watercolors. (PP at the end, Passive Voice)
Using watercolors, the artist drew this portrait. (PP at the front, Active Voice)
The artist drew this portrait, using watercolors. (PP at the end, Active Voice)
I get confused when I want to use present participles acting as adverbs. How we should use comma in these cases? In terms adverbial clauses with subordinate conjunctions, I know how I should use comma. It is very straight forward.
Similar things on the Internet:
In this link, and on this page, there is a bunch of discussions in the case of the present participles coming at the end of a sentence.