Caddie is described as 'Provides designers with all the tools they need to sketch, design, detail and visualise their ideas in 2 and 3 dimensions, to produce superb quality drawings full of character and stunning 3D images that bring their designs to life' and is an app. There are more than 25 alternatives to Caddie for a variety of platforms, including Windows, Mac, Linux, Web-based and Android apps. The best Caddie alternative is Autodesk AutoCAD. It's not free, so if you're looking for a free alternative, you could try MakerSCAD. Other great apps like Caddie are DraftSight, ArchiCAD, ZWCAD and Renga Architecture.