I am currently working in my master thesis, It is a study case in Madrid, more precisely about an office building, quite a complex building.
The floor I am going to further analyze has a wooden slats ceiling, I have modeled it myself but every time I run a simulation It requires one or two days at least, even with the lowest quality. I wonder if there is any other way to mimic the effect that these features have on the overall daylight performance. See the attached image to support what I am talking about.
I think if you simplify the model by replacing slats with one surface with a certain amount of light transmittance according to the number and total area of slats in a certain unit of surface area.
But before that, you need to find the right amount of transmittance by reviewing the literature or conducting field measurement.