The use of 3D and Virtual Reality is gaining interest in the context of academic discussions on E-learning technologies. However, the use of 3D for learning environments also has drawbacks. One way to overcome these drawbacks is by having an adaptive learning environment, i.e., an environment that dynamically adapts to the learner and the activities that he performs in the environment. In this paper, the authors discuss adaptive 3D virtual learning environments and explain how a course author can specify such an environment (i.e., authoring). The approach and tool that the authors present allow authors to create adaptive 3D virtual learning environments without the need to be an expert in 3D or using programming or scripting languages. The authors also conducted an evaluation to validate the approach and the usability and acceptability of the authoring tool. Based on the results, recommendations for authoring adaptive 3D virtual learning environments have been formulated.