Nonuniform shape shading device

I am trying to define the area for shading device installation by setting a threshold for solar irradiation. The shading device is only installed on the area that meets the threshold. As a result, some meshes in non-uniform shapes are generated (picture 1). However, not sure whether it is due to 1) the unstable conversion of mesh to brep (picture 2) or 2) the complex geometry of the shading devices, the energy simulation takes forever to run.

May I ask 1) if anyone performed energy simulation with complex geometry shading device? 2) And if that is the reason of long simulation duration, is there any way to simplify the geometry (same size) in order to solve the problem.

Thanks a lot.

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