OneCNC 's simulation checks for tool gouging in a theoretical rectangular cube which represents the space occupied by the stock. Rapid moves, and feed moves are checked.
Other movements such as movements to and from machine home or the toolchange position are not checked. The assumption is made that you have the knowhow to get the tool safely over the part.
In more complex setups, you can also use OneCNC's toolpath preview mode. This shows everything that you have modelled on screen, which might be your stock, some clamps, a chuck, or whatever else you take the time to model or import into your file, and when you run the preview, the tool motion is shown. Gouge check is not done at this time, but you can visually see if you might have interference with something. The speed of the preview is variable, and can be slowed down as low as 'single step'. The coordinates of the tool center are visible in the upper corner.
As for the post, all you need to do is supply tech support with a typical program or pages from your controller manual, showing the structure of the gcode syntax for that controller, and they can adjust the default post to suit.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)