What are some alternatives?
When comparing PathEngine and SelfCAD, you can also consider the following products
EQUINOX-3D - EQUINOX-3D offers 3D modeling, animation, photorealistic rendering, photorealistic VR content creation, CAD/CAM, 3D printing, laser-cutting and more.
MilkShape 3D - The MilkShape 3D website has been down for almost one week.
Aartform Curvy 3D - Aartform Curvy 3D is an easy and fast sculpting program for Windows.
Autodesk Tinkercad - Tinkercad is a super easy-to-use, browser based 3D design tool.
Clara.io - Free online 3D modeling software: Design, editor, animation, rendering, & lots of free 3D models. Supports Three.JS, Blend, FBX, OBJ, V-Ray, Babylon.JS, STL.
Substance Designer - Substance Designer is a node-based non-destructive application for material authoring.