SketchUp lets you do 3D modeling in your web browser. With Sketchup you can create all kinds of assets and objects to use in your game—buildings, tools, barrels, fencing, and more. You’ll probably need to go through some tutorials before you get started but once you’ve learnt the basics you’ll be able to make a lot of different things.

SketchUp has related websites that may also help you make your game; Extension Warehouse offers a lot of plugins for that can add functionality to your version of Sketchup, while 3D Warehouse hosts a huge variety of user-made 3D models you can download and use—from boats and sofas to dogs and flowers.

• SketchUp have a number of 'tracks' on their website to guide you through using each element of their tool.
• Check out the SketchUp YouTube channel for videos on how to use the tool
• Get the tool here.