Signing avatars make it possible for deaf people to access information in their preferred language. This paper describes the implementation of a new 3D high-realistic avatar, for Greek Sign Language (GSL) fingerspelling and numbering signs. This research study explores open-source 3D platforms such as MakeHuman, Blender, and Unity’s game engine as 3D rendering architectures. Creating signing virtual characters is important for training and communicating in virtual environments or further applications. This research looks at how to use the power of C# unity script code and layered motion game technology to achieve programmable transitions of animation segments and to create dynamical, real-time (on the fly), natural, and understandable outputs with controllable playback speed and playback views. Another novelty of the proposed scheme focuses on the precision of the transition time and how it blends between the last sign posture (first sign) and first sign posture animation (second sign).