How to smooth edges in Sketchup free

Smoothing edges in Sketchup can only work for 1 object, using the auto smooth tool will automatically make many objects at the same time and faster.

Video tutorial:

Steps by steps :

• • Select object – choose Edges tools
  • Edges are smoothed, faster than using default Sketchup, and can also do many objects at the same time
  • Opposite to unsmooth select object – click on auto unsmooth edges
  • Unsmooth edges helps you show surfaces and object edges for easy detailed design

How softening works under the hood

Behind the scenes, “smooth” and “soften” are two separate edge properties that Sketchup almost always toggles together. Softening hides the edge and merges the two faces it borders into a single curved surface entity, while smoothing only changes the shading so the surface looks rounded instead of faceted. Because softened edges still exist in the model, your geometry is never simplified – softening is purely cosmetic, so a 10,000-edge sphere stays a 10,000-edge sphere even when it looks perfectly smooth.

A non-obvious gotcha lives in the native Soften/Smooth dialog’s “Soften coplanar” checkbox: turning it on deletes every edge that sits between two flat, in-plane faces, permanently merging them – this is great for cleaning up imported meshes but will silently destroy edges you may have wanted to keep, and there is no separate undo for it beyond Ctrl+Z. The angle slider above it (20 degrees by default) only softens edges where the two faces meet below that threshold, so cranking it toward 90 degrees can flatten the look of an entire model in one click.

Faster way: the Eraser shortcut

If you only need a few edges gone, you don’t need any dialog at all. Hold Ctrl and drag the Eraser tool over edges to soften+smooth them instead of deleting them, and hold Ctrl+Shift to un-soften them back – this is the quickest manual method and works on any selection without opening a panel. Selecting a group or component first lets you soften many objects in one pass, which is the same result the auto-smooth tool above gives you with a single click.

A note on “Sketchup Free”

This workflow assumes the desktop app (the current release is Sketchup 2026). If you are on the browser-based Sketchup Free, there is no Soften/Smooth panel and no extension support, so you are limited to the Eraser Ctrl-drag trick for softening – the auto-smooth extension shown in the video only runs in Sketchup Pro on desktop. Sketchup has been a named-user subscription since 2020, so there is no longer a one-time perpetual license for the Pro edition.