Often, if you lay out 3 points in space and then triangle brush them, VoxelSniper will place blocks that are obviously outside of where the triangle should be, by any definition. For instance, put two blocks at the same Y level, and one below somewhere, and the brush will create a few blocks ABOVE the Y-level that the two highest corners share. Which makes absolutely no sense, and I'm assuming its some sort of +1 error in the code somewhere.

When you're creating geodesic surfaces (complex curves made up of many many little triangles), it becomes a huge problem, because the extra, incorrect blocks that get places screw up the smoothness of the surface considerably.