  3D meshes are one of the main components of Virtual Reality applications.
However, many network and computational resources are required to process 3D
meshes in real-time. A potential solution to this challenge is to dynamically
adapt the Level of Detail (LoD) of a 3D mesh based on the object's position and
the user's viewpoint. In this paper, we conduct a subjective study to
investigate users' quality perception of 3D meshes with dynamic Level of Detail
in a Virtual Reality environment. The subjective experiment is carried out with
five 3D meshes of different characteristics, four Levels of Detail, and four
distance settings. The results of the experiment show that the impact of the
dynamic level of detail depends on both the position of the 3D object in the
virtual world and the number of vertices of the original mesh. In addition, we
present a quality model that can accurately predict the MOS score of a LoD
version of a 3D mesh from the number of vertices and the distance from the
viewpoint.
