I'm not sure exactly what you mean, do you have a file or an image you can share?
I just learned that it adds the depth on top. Here is an examples that follows the levels. However, it plunges into the part.
I thought helix would prevent this.
As a Finishing toolpath, the Horizontal toolpath is not aware of the stock, and the same goes for pretty much all of the other Finishing toolpaths (Contour, Scallop, Flat etc etc). The Horizontal or Flat toolpath should primarily be used for finishing, keeping in mind it's not designed for stock awareness. I'd recommend using a 3D Pocket (or Adaptive) toolpath to rough this part out.
@ian1196 wrote:
I always give Adaptive a chance and it is mostly junk.
How so, do you have an example you can share (where the toolpath is less than desired)?