Modelur - Save time and make well-informed decisions during early stages of urban design.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
CityEngine - CityEngine is a 3D modeling software application that uses the method of procedural generation to facilitate urban modeling and design on a massive scale.
SelfCAD - SelfCAD is an online 3D modeling and slicing software.
3D Cityplanner - Urban and real estate development at your fingertips. With the 3D Cityplanner it’s possible to create, visualize, analyze and share 3d plans online.
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.