Посоветуйте какой-нибудь хороший игровой движок с невысоким порогом вхождения для новичков 3D!?

Тебе весь список? И вообще для какого жанра? Вот тебе список наиболее популярных движков/конструкторов игр:
| 3D Action Maker | 3D Game Maker | 3D Game Studio | 3D Rad | 3D Rad Rus | 3D Мастер | Adobe Flash | ADRIFT | Advanced RPG Maker | Adventure Game Studio | Adventure Maker | Alice | Awakening | Blade Engine | Blade3D | Blender | Byond | Construct | DevelStudio | Dimension3 | Dizzy Quest Editor | DizzyAGE | DS Game Maker | Dungeon Craft | e-Adventure | Eclipse | EMG Studio | Engine001 | Enigma | Esperient Creator | Explorations | Fighter Maker 95-2002 | FPS Creator | FPS Creator X10 | G-Creator | GAGE | Game Editor | Game Maker | Game Weaver | GameBrix | GameSalad | Genesis 2D | Golden Realm | HiAsm | IsoEasyEditor | J.U.R.P.E. | M.U.G.E.N | Mario Worker | Milena | Mo'Minis | Mokoi Gaming | MultiGen-Paradigm Creator | Multimedia Fusion | Novashell | Novelty | Nream! | O.H.R.RPG.C.E | Open Legends | Open Zelda | Platform Games Editor | Platform Studio | Platinum Arts Sandbox | PlayCrafter | Point&Click Dev Kit | PsOne Development Studio | QCake | Quest 3D | Quest Soft Player | Racer | Ray Game Designer | Raycasting Game Maker | Reality Factory | Realm Crafter | Ren'Py | RPG Builder 3D | RPG Maker | RPG Studio | RPG Toolkit DS | RPGDTE | RTADS | Rumblah! | RuneSword | Sauerbraten | Scratch | Scrolling Game Development Kit | ShugenDo | Silent Walk FPS Creator | Sploder! | Stagecast Creator | Stratagus | STUG Builder | The Games Factory | Unity | URQ | vbGORE | Verge | Virtools | Visionaire Studio | WinPAW | Wintermute Engine | XtremeWorlds | ZGameEditor | Алгоритм |
| 3D Game engine | 3DCakeWalk | 3Impact | Abyssal Engine | Airplay SDK | Aleph One | Alternativa3D | Andorra 2D | Antiryad Gx | Apocalyx | ArcEngine | Ardor3D | Arianne | Asphyre | Blitz3D | Bootstrap Engine | Brutus2D | C4 Engine | Ca3D-Engine | CAST II | Chocolate Doom | CopperCube | CryENGINE 3 | Crystal Space | CSP Game Engine | DarkBASIC | DarkPlaces | Demoniak3D | DEngine | DGLEngine | Doom Legacy | Doomsday | DX Studio | EDGE | Empty Clip | Entidad 3D | Esenthel Engine | Eternity Engine | Existence engine | FBA | FIFE | G3D Engine | Gamebryo Casual | GameBryo Element | GameCore | Genesis3D | Glest | GLHeretic | GLHexen | GLScene | GZDoom | Haaf's Game Engine | Havok | Horde3D | Irrlicht Engine | JMonkeyEngine | Jolt3d! | LawMaker Game Engine | Leadwerks Engine | LinCity | Linderdaum | LKI-Creator | LKI-Creator 3D | LOVE | Mark IV Engine | MobileDragon | Nebula | NeoAxis | NetGore | Ninfa3D | Nytro Game Engine | Odamex | Ogre | OMEGA | Open Sonic | OpenBOR | OpenSceneGraph | Original 3D | ORTS | Panda3D | Pipmak | Pixie | PrBoom-plus | Pygame | Q3A | Qfusion | Quake II | Quantum Engine | Raydium Engine | ReLi | ReMooD | Retribution Engine | Risen3D | S2 Engine | Sandy3D | ScoreDoom | ShiVa | Skulltag | SNAP Mobile SDK | Spring | SpriteCraft | StemCell Game Engine | TDG 3D | Tokyo Game Engine | Torque 3D | Torque Game Engine | Truevision3D | Unigine | Unreal Development Kit | Vatan Engine | Vavoom | Vision | Visual3D | WinDoom | ZDaemon | ZDoom | Zombie Engine |
Для стрелялки: РГМ. Для других жанров: Game Maker, Map 001, Construct... их дофига! Залезь - ка ты на gcup.ru там тебе помогут!

glScene для Delphi
ogre для C++
но это все графические движки, я только с этими знаком