Depending on the ingredient, nozzle size and print you are doing, you may want smoothing function on or off.

In general, the smoothing function is not needed when you are using small nozzle sizes and sticky ingredients. Sometimes smoothing will result in too much ingredient at the end of your print. It depends on what you are printing. 

Here is an example of a print where smoothing function ON produces a better result versus when it is off. This print was using a 4.0 nozzle with mashed potato as the ingredient: a larger size nozzle and non-sticky ingredient.

(See this video in youku/ 请观看优酷视频)

In the final print result, you can see the fish on the right has a better, smoother finish, as the ending print path was extended using the smoothing function.

Theses were the Edit Image settings used for each print: