Form a spiral chair seat from welded, rotated curves

Roughing out a swooping chair seat and back with default SketchUp tools prior to a high-poly subdivision with a specialty plugin.

Note: A face encircled by a welded curve entity is easy to manipulate. Before SketchUp 2020, one needed a plugin to weld edges. The first Weld plugin was developed by RickW. In 2020, the SketchUp team added weld to the program.

To set up a keyboard shortcut for this context menu item, pre-select the edges. Then go to Window > Preferences > Shortcuts.

Now go to town...


Autofold

Use a subdividing plugin to finish.