Teachers and trainers make pedagogical decisions for their training courses, so why not do the same for Virtual Reality (VR) training courses? Virtual Environments for Training (VETs) are becoming prominent educational tools. However, VET models have yet to propose scenario authoring aligned with pedagogical objectives that can account for the diversity of approaches available to teachers. This paper proposes a scenario authoring model for VET that directly involves domain experts and validates their pedagogical objectives. In addition, it proposes the coexistence of multiple pedagogical scenarios within the same VET, using three types of scenarios. The validity of the model is then discussed using a VR welding application as a use case.