Is shader model 3.0 require for assassin creed if have 512mb nvidia graphic card with direct 10 x complitable

Yes
check out the system requirements Minimum System Requirements
OS: Windows XP/Vista
Processor: Intel Pentium D Dual Core @ 2.6 GHz
Memory: 1 Gb
Hard Drive: 8 Gb free
Video Memory: 256 Mb
Video Card: nVidia GeForce 6800 / ATI Radeon X1600 support Shader Model 3.0
Sound Card: DirectX Compatible
DirectX: 9.0c
Keyboard
Mouse
DVD Rom Drive
Recommended System Requirements
OS: Windows XP/Vista
Processor: Intel Core 2 DUO @ 2.2 GHz
Memory: 2 Gb
Hard Drive: 8 Gb free
Video Memory: 512 Mb
Video Card: nVidia GeForce 8800 / ATI Radeon HD 2900 support Shader Model 3.0
Sound Card: DirectX Compatible
DirectX: 9.0c or 10
Keyboard
Mouse
Other Controllers: XBOX 360 Controller for Windows
DVD Rom Drive