PEN tool and better inferencing system ala Sketchup?

I like Rhino a lot, have a lot of fancy features, but unfortunatelly seems that still are missing basic tools to make this software more productive.

I want to cut a surface by a Line and I can’t find a proper way to do this. In Skethup, if you are using the PEN tool you can draw a line like mine and after that it is sensing that can be two different faces and after that you can select one of the pieces of the face and delete-it.

CutSurface_by curve.3dm (24.6 KB)

I would love to see in Rhino a tool similar to the PEN tool so I can just draw a line in a surface and Rhino to sense automatically to chose the whole face or only one side-part of the face.

Also the “Inference” system in Skethup is the best. You don’t need to think how to do basic stuf, everything it is just snaps where you need to snap. Developers please take a look at Sketchup how FAST you can do basic stufs. In Rhino I spent half an hour trying to figure-out how to cut this face using the drawn line and still I could’t foud a solution.

The commands are called “Split” or “Trim”. Check the Help for more info. --Mitch

Yes, thank you, my question was different. It will be great just to pick-up a piece on one side of the geometry and dele-it or extrude-it or whatewer. Please check Sketchup how fast it is doing this sort of things.

Don’t expect Rhino to work like Sketchup, nor Sketchup to work like Rhino. Sketchup only works with flat faces - which are just closed polygons - whereas Rhino works with NURBS surfaces that can be flat or curved. So such a tool as you describe could be made in Rhino, but the consequences would be that it would only work on certain planar-faced structures and not on others.


That will be great as 99% of the time I’m working with flat surfaces.

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 :wink: )

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)


@jeff_hammond elaborated nicely on what I meant by



For this simple type drawing trim is the champ. Draw your line Crtl + T then select the item you want to go away… Very easy.

Hi @Macuso,

If you are coming from SketchUp, this video might also be helpful.

– Dale

I’ve seen this video a few times and helps a lot, unfortunatelly are a lot of unnecesarry suplimentary steps that needs to be made in Rhino compared with Sketchup, because seems that Rhino don’t have (as mentioned in other thread) any kind of direct editing capabilities.

So my hope is to see in Rhino some very basic direct editing tools, better inferencing system and some basic parametric capabilities like the old plugin RhinoWorks was able to provide.

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Just extrude your line in both sides and use it like element to cut with split

A lot of people want it

I hope soon someone develop some to do that