Correct settings for the calculation of illuminance of objects can be seen by the details of the objects. Curved edges that show aliasing effects such as sharp edges or hard transitions require less computing power.
Often, the calculation times can be reduced many times over if only a few sample points are smoothed and gathered. While this shortcut is not visible on smooth surfaces, the error will be visible on small, complex forms. This aspect is relevant where details have high luminance contrasts. This is similar to the luminance progression on component edges or the weak shadow of an object due to excessive interpolation of the shadow-effect in the room.
If the grid is too coarse and the components are not accurately connected, the light distribution can be wrong, resulting, for example, in light apparently shining through a wall or a ceiling.

Room with few sample points

Room with numerous sample points

Shadow with strong interpolation

Detail shadow with strong interpolation

Shadow with good interpolation

Surfaces with few sample points