While Solid Tools existed before (Union, Subtract, Intersect), the 2018 version introduced better error reporting. If a boolean operation failed, the software now told you why —specifically which edges were non-manifold or inverted faces.
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Have you used SketchUp Pro 2018? What is your favorite hidden feature? Share your experiences in the comments below. sketchup pro 2018
: It is highly recommended to Group (Right-click > Make Group) or create Components for your 3D objects to prevent them from "sticking" to each other. View and Interface Setup While Solid Tools existed before (Union