Alternatives. What could replace Curviloft?
Direct substitutes
1001bit ToolsSketchUp tools for simple architectural elements: stairs, openings and construction details.
CleanUp³CleanUp³ is a free SketchUp extension that strips unused geometry, materials and duplicate faces to shrink and tidy large model files.
Eneroth Face CreatorFree SketchUp extension by Christina Eneroth that automatically generates all possible faces from a selection of edges.
FlexToolsSketchUp extension for architects and designers. Creates parametric, responsive architectural elements (doors, windows, stairs). Includes WallCutter for automatic opening creation in layered walls.
Fredo6 BundleFredo6 Bundle is a collection of over 40 free SketchUp modeling plugins (FredoScale, Curviloft and others), with a couple sold separately.
FredoCornerPaid SketchUp desktop extension that rounds, bevels, subdivides, or chops the corners of 3D shapes. It requires LibFredo6 and SketchUcation ExtensionStore.