Blender Powerful and professional 3D modelling software which can create models, animation, shading and works with a number of file formats.
Google SketchUp 3D modelling app which can be used to draw models with polygons, circles, lines providing import and export operations to Google's warehouse.
draw.io Desktop Utility to create classy diagrams with drawing tools, 2D and 3D shapes, arrows, annotations and more with the option to print.