Calculate percent shading on surface


I need to figure out how to calculate shading % on a surface. I figure I can sort of do it manually by setting Parallel Projection with a view perpendicular to the surface(s), and then… counting? ugh.
Oh, the surfaces might be a bunch of co-planar but separated surfaces (think: solar modules), so it would be nice if either it were fast & easy per surface (lots of repetition), or could be done on a bunch of surfaces at once. Assuming there is some clever way to do this.
Let me know if that’s not clear.
Thank you.


BTW, if there is no ready way to do this, I might be interested in building a plug-in to do so: is that likely to be possible? Any similar plug-ins I might be able to steal from, design-wise? Do people do that?


Sefaira is another Trimble product aimed at energy analysis of buildings. They convinced our Moderators to open their own category here on this forum:
There are a couple of subcategories, including one for their Sketchup plugin.

I’ve not looked into it beyond a bit of browsing on their website (linked above) for a few minutes when the forum category first appeared, but it seems to me they MIGHT have a solution for you. Not directly in Sketchup, but they have a plugin that connects (I assume) to their cloud platform and might have the sort of analysis you need.


Also check the Extension Warehouse for other shadow study extensions.


I’ve used this one with some success:
Lets you hover over a given part of the model and tells you how many average hours of daylight a spot gets on a given day.


We have a version of Shadow Analysis plugin which does calculate shading %. It is not published yet, but if you would like to have a look at it please email me at and you can join our beta testers.