A specific design of craniofacial implant model is vital and urgent for traumatic head injury. A mirror technique is conventionally employed for modelling. However, such method requires healthy skull region identically opposite to a defect. We therefore propose the three processing workflows for modelling implants: mirror, baffle planner and baffle-based mirror guideline. The workflows are based on implementing extension modules on the 3D Slicer platform. We investigated the craniofacial CT datasets collected from the four accidental cases. The designed implant models were created from conducting the three workflows and compared to the reference models created by the experienced neurosurgeon. The spatial properties-based performance metrics were evaluated. The results show that the mirror method suits craniofacial cases whereby healthy skull region can be completely reflected to the defect region. The baffle planner module offers a flexible prototype model fit independently to any defect location. However, the baffle planner method requires customized refinement of contour and thickness to fill the missing region seamlessly. The process also relies on a user’s experience and expertise. The proposed baffle-based mirror guideline method strengthens the baffle planner method by tracing the mirrored surface. Such three proposed workflows simplify craniofacial implant modelling and can practically be employed for a variety of craniofacial scenarios.