SketchUp, Blender, Sketchfab, Autodesk Maya, Autodesk 3ds Max, Rhinoceros, Fragmentarium, Houdini, Art of Illusion, Sculptura, picoCAD, Wings 3D, Animation Master, Anim8or, Putty3D, Bforartists, GroBoto, Structure Synth, KenShape, RealFlow, Akeytsu, Now3D, Realsoft 3D, VoidWorld, CharacterFX, Seamless 3d, AutoQ3D Animation are some alternatives to K-3D.