it’s not just the Line tool (ie- the one with the pencil icon)…
it’s a fundamental difference between the two softwares.
in Rhino, you can cross two lines (say, make a +) and they will remain two lines which are still individually selectable…
if you do that in Sketchup, you’re left with 4 lines which are stuck together with a vertex at the middle… (vertex since you’re using meshes in Sketchup)
when you place geometry over other geometry in sketchup, regardless of which tool you’re using, the pieces will split and merge… everything sticks together which in some instances, this may be desirable but as a whole, i personally prefer the way things work in Rhino.
anyway, point being-- it’s not a single tool that’s doing this in Sketchup… it’s the way the entire program works…
and if you wanted Rhino to work this way, you’d have to change the entire software from the ground up.
although, in Rhino, it would be possible to create a script that does what your specific example shows…
basically, a script that allows the user to draw a Polyline
over a surface then it automatically Splits
the surface then Joins
the surface pieces together.
This would somewhat mimic what happens in Sketchup but only to a certain degree… the resulting piece will be split and joined but doing further operations still won’t act as a mesh as they would in Sketchup.
they’re fundamentally different… at the very root level… you can’t just make a single tool for Rhino in order for it to behave like Sketchup… you have to make a whole bunch of tools in Rhino to do that (basically, change all of them
)
[ADD]
as far as inferencing goes, yes, some of Sketchup is more user friendly or more practical (imo)…
(it incorporates some of what we see in Rhino’s SmartTrack in a more fluid manner)… the main problem is you can’t turn any of that stuff off… you have no control over tracking and snapping in SketchUp… many times, you may not need or want ,say, midpoint snap in SketchUp… well, too bad… it’s permanently on.
to me, the best thing that could come from SketchUp to Rhino is that it has vertical inferencing as opposed to explicit ‘elevator mode’ in Rhino…
(but if McNeel were to incorporate this into Rhino, mimic Moi instead… it goes vertical too but, imo, better than SketchUP)