Polysketch

The ultimate low poly 3D modeling tool! Sketch out your lines and surfaces like drawing on paper, then use a few key tools to add color, detail and modify. Simple, intuitive tools keep you focused and creative - then export a clean, game-ready mesh for prototypes, 3D printing, or just getting creative from the couch.

We've found Polysketch is great for:

~Game dev and prototyping (Unity, Unreal, etc)
~Custom objects and worlds in VR Chat and Roblox
~Tabletop game creatures and props, to be 3D printed
~Concept art paintovers

Instead of many complex tools, Polysketch focuses on simple, natural 3D sketching to create your shapes. It's like paper, but simpler because you don't have to learn perspective ;)

You can export your creations as standard "OBJ" files for use in almost any app (Unity, Blender, etc). Even better, the line-sketching method ensures a clean and game-ready 3D mesh, so you can use it right away!