How do you soften a circle ?

Hi everyone,

I just want to soften a circle, in sketchup 2026.
Not smooth it, not hide it.

If I explode the circle, and select all the edges, the Soft/Smooth boxes are available,
And I can just tick the Soft box.
But if I keep it a circle, or make it a curve, it disapears:


It’s the Japanese UI

・Why are these checkbox not available on Circle and Curves?
(if there is no reason, I’d be happy to see them back in sketchup 2027)
・Is there a way around it ? - other than exploding the circle obviously.

Thanks!

You know you can use ctrl with the eraser to soften.
GIF 14-05-2026 5-04-38 PM

1 Like

Thanks Box,
But Ctrl with the eraser smooth the edge, and I don’t want that.
In fact I wish there was a modifier key with the eraser that only soften an edge.
I submit ALT.

Thanks a lot Mihai!
As always :rofl:
That’s the way to do it then. I didn’t see that checkbox in the soften edges tab!
I would be happy if the checkbox are made available in the entity property (more accessible in my opinion), but for now my problem is solved!

If you make the shape with lines + arc, then weld the line + arc and use Follow Me the transition from cylinder to dome will be softened.

Thank you very much Mike!
True, this way the line is softened. But it is also smoothed, and that is what I try to avoid.
I want that transitional edge between the cylinder and the dome to be sharp, but not visible, Except as an outline edge. Which is why hiding it won’t do the trick either.

Also this image I posted is just an exemple to illustrate a problem I’ve had in various situations.
And very often this edge won’t come from a follow me operation or from a shape that can even be made with follow me.
A way to fix the edge after the geometry is created is what I would need most of the time.

How about not using smooth/soft, but using just Hide pn that circle ? Everything else will be ‘smoothed’, but there will now be a ‘sharp’ change of surfaces at the circle ?

I would either

Use the soften and smooth slider bar
This will soften the sides of the cylinder and the top of the object, but keep the transitional hard edge of the edge.
If you turn off edges /profiles you will see it without SketchUp edges.

Or if you also want to hide the edge, select the round edge after using the soften/smooth bar and toggle the visbility with the eye.

Some aspects of softening and smoothing are functionally hiding it.

Thank you TIG!

It is mostly because the outline that this edge defines is a visual cue that I want to keep.
It helps understanding the shape from any angle, but mostly it looks nice and consistant.
Here is the difference in picture:
Left : Hidden Edge / Right : Softened Edge

There is a variety of cases where i’m in this situation where where hiding the line completely breaks my visuals.

As a side note, it is really something I like in sketchup:
The ability to control Smooth and Soft separately !
I use “Soften only” a lot.

Thanks Adam!

Right, toggling the edge visibility off works in that case.
But only as long as the model is just about this single bloc. In the context of the full project, all the edges in the rest of the model would disapear too…
For the sake of clarity I just zoomed in on one piece of geometry,
But I really want to have this specific edge to be soft, and behave differently than all the other hard edges of the model.

Thanks and you’re welcome!

I asked Gemini AI to generate ruby ​​code that softens (without smooth) circles or curves with the press of a key.
This is the code and it’s working fine (tested in SU 2026).

:downwards_button:
soften_curves.rb (948 Bytes)

As Dezmo says with every code he offers to the public: No warranties! Use at your own risk!

require 'sketchup.rb'

module MSssc
  def self.soften_selected_curves
    model = Sketchup.active_model
    selection = model.selection

    if selection.empty?
      UI.messagebox("Te rog să selectezi un cerc sau o curbă mai întâi. Please select a circle or curve first.")
      return
    end

    model.start_operation('Soften Curves Only', true)

    selection.each do |entity|
      # Verificăm dacă entitatea este o muchie (Edge) și face parte dintr-o curbă
      if entity.is_a?(Sketchup::Edge) && entity.curve
        entity.soft = true
        # entity.smooth = false # Opțional: ne asigurăm că Smooth rămâne dezactivat
      end
    end

    model.commit_operation
  end
end

# Adăugăm opțiunea în meniul 'Extensions' pentru a-i putea atribui un Shortcut
if not file_loaded?(__FILE__)
  menu = UI.menu('Plugins')
  menu.add_item('Soften Selected Curves') {
    MSssc.soften_selected_curves
  }
  file_loaded(__FILE__)
end

  • How to install and use the script:

Saving the file: Copy the above code into a text editor (like Notepad or VS Code) and save it with the extension .rb (for example: soften_curves.rb).

Location: Place the file in the Plugins folder of SketchUp.

Windows: %AppData%\SketchUp\SketchUp [Year]\SketchUp\Plugins

Enabling Shortcut:

Open SketchUp.

Go to Window > Preferences > Shortcuts.

Look for Extensions/Soften Selected Curves (or the name you gave it in the menu) in the list.

Assign the desired key to it (for example, a shortcut that is not used).

  • Why is this script useful?

Unlike the standard Soften/Smooth Edges dialog, which often works based on angles between faces, this script attacks the Curve or Arc object directly. This way, you don’t risk “spraying” soften on other adjacent geometry if your selection is precise.

If you want to modify the script so that it also does Unsoften (reduce to visible lines), you just need to change entity.soft = true to false.

by Gemini AI

I think I understand - there are definitely some anomalies when I tried to do this as I would normally do it - even the soften and smooth tray behaves different on a freshly drawn circle versus the same circle after push/pull.

In my mind softening is only about maintaining certain segmentation whereas the smoothing is what controls normals and thus lighting/appearence.

Maybe I’ve got a misunderstanding of what those differences are? It looks as if it does perhaps change the way profiles are rendered too - which I suppose is what you are leveraging.

Anyways, one workaround in the UI is to select both the circle and another edge at the same time - which will expose soften and smooth for all selected entities and allow you to apply just the soften checkbox

In SketchUp, “soft” means that if there are two visible faces that share that edge, they are treated as portions of a surface. You can select them as a single unit (note: they are not a group or component. There is no wrapper that isolates them from interaction with other edges and faces). “Smooth” means that the shading of the faces is blended across the edge, causing the join to look, well, smooth.

I love it :heart_eyes:
A simple shortcut to soften the selection, That’s exactly the way i prefer working in sketchup.
In fact for Smoothing or Unsmoothing selection I already use shortcuts (thanks to the good old JHS powerbar). And same for Hide/Unhide.
“Soften” is an outlier as it has no shortcut on the eraser tool (…that I know of?)
And I’m not aware of any specific extention that focus on Soften, without Smoothing.
Untill now… Because you just made one!

Since you put it here, I’m wondering if there is a way to tweak it so that it simply soften any edge in the selection. Should it be a circle, a curve or a simple edge. At this point, this is already more useful to me than the regular “soft” checkbox in the entity info, or the soft/smooth tab in the tray. Both of these requiring more mouse movements and clicks, and screen space used by the UI…

I should try to play around with it!

If you have the eraser tool activated and press the shift key, what does that to to an edge?

Oh true! It didn’t even crossed my mind…
Selecting an additional edge to get the Soft checkbox reappearing.
I’ll probably do that often. As I’m trying not to rely on the soften edges tab too much. (Scrolling in the trays kills my modeling mood :sweat_smile: )

Now the fact that these check box in the entity info pops in and out of existance - depending on the nature of the lines selected - don’t feel consistant. And even counter-intuitive.
As you put it “Anomaly” is the right word.
Hopefully it get fixed, unless there is a good reason, and it is a deliberate UI choice???

That hides it.

And it doesn’t soften it.

Indeed, the only reason why I use “soften only” is to get this control over edge visibility. Keeping them invisible, unless they become profile edges, when the camera angle is right.

I asked Gemini AI to make the requested change and this is the new plugin.

:downwards_button:
soften_curves.rb (864 Bytes)

Replace the previous plugin with this one and you will be able to soften any selected edge (simple, arc, circle, curves). You will need to add the shortcut again to ‘Soften any selected edges’.
I tested it in SU2026 and it works.

No warranties! Use at your own risk!

require 'sketchup.rb'

module MSssc
  def self.soften_all_selected_edges
    model = Sketchup.active_model
    selection = model.selection

    if selection.empty?
      UI.messagebox("Te rog să selectezi geometrie (muchii) mai întâi. Please select geometry (edges) first.")
      return
    end

    model.start_operation('Soften Any Selected Edge', true)

    selection.each do |entity|
      # Verificăm doar dacă entitatea este o muchie (Edge), indiferent dacă e curbă sau nu
      if entity.is_a?(Sketchup::Edge)
        entity.soft = true
        # entity.smooth = false # Rămâne dezactivat, conform cerinței inițiale
      end
    end

    model.commit_operation
  end
end

if not file_loaded?(__FILE__)
  menu = UI.menu('Plugins')
  menu.add_item('Soften Any Selected Edges') {
    MSssc.soften_all_selected_edges
  }
  file_loaded(__FILE__)
end