Here’s another application for KDE, which allows you to use 3D effects. Misfit Model 3D is an OpenGL-based 3D model editor.
It supports multi-level undo, skeletal animations, simple texturing, scripting, command-line batch processing, and a plugin system for adding new model and image filters. Complete online help is included. More recent develpment versions are also available. See the official homepage for details.
Homepage: Misfit Model 3D.