3D Object Maker compatible with models in STL, OBJ and 3DS format. You can export your work ready to print in 3D (STL format) or to keep working on it later (SCENE format).
Github: https://github.com/lrusso/3DObjectMaker
Web version: https://lrusso.github.io/3DObjectMaker/3DObjectMaker.htm
App version: https://play.google.com/store/apps/details?id=ar.com.lrusso.dobjectmaker
Cutting and fusion objects is also possible within the tool