In a few areas of my project is keep getting this issue (see images attached) when import my model from sketchup to twinmotion.
Im currently using Sketchup Pro 2021 and Twinmotion 2025.1.1
This has been an issue for the last few months and honestly I am discouraged from even using twinmotion until its fixed.
is the top image with the backside of the default material in white?
Can you post it with backface in black or red for discussion purposes? Using styles in sketchup? I would bet its the normal issue. Not easy to spot in SU bc you can paint backfaces.
I get this kind of issue often, if it doesn’t resolve when you make the material two-sided in Twinmotion, it usually does when you simply explode the object in Sketchup until it reaches surface level and then group everything again. Maybe it isn’t the most delicate method but it is certainly effective. 
