I have just downloaded the programme and ready to start rendering. Initial tutorial on website works fine. HOW do I upload a 3D file (STEP, OBJ, STL etc) to get started? If anyone can advise I would be very grateful.
You can use one of our supported digital content creation applications (Blender, Max, Maya) to load 3d files and then render the scene with the suitable appleseed-plugin from within the application.
The latest versions of the plugins you can find in the #builds channel of our Discord server.