In the 3D-modelling universe, the Level of Detail has a crucial role, as it is the case to assess the PV potential in urban environments using this kind of models. According to the CityGML standards, there are five levels of detail, going from the footprint (LOD0) to a precise model with inside and outside details (LOD4) as stairs and chimneys. For the subject we are studying, meaning the assessment of the PV potential, the inside details are totally superfluous. That is why we are going to consider the LOD3 model as a perfect model. But an LOD3 model costs a lot more to do than an LOD1 or LOD2. This brings us to the main question we will try to answer in this paper: Is it useful to do an LOD3 model, or are LOD1 and LOD2 models precise enough to assess the PV potential of a building, or even of a city? The second part of the paper will handle the theme of the shading effects. Indeed, the production of electricity of PV cells is affected when a part of the cell is shaded. Therefore, what would be the consequences on the PV potential if all the zones unregularly lit by the sun were considered as unusable for PV cells? This is the second question to be answered in this paper.