Hidden Surface Removal for Accurate Painting-Area Calculation on CAD Models

3D CAD models are widely used to improve management of large-scale engineering projects. Examples include Building Information Modeling (BIM) and Oil & Gas industrial plants. Maintaining these facilities is a critical task that often involves anti-corrosive painting of equipment and metallic structures. Existing CAD software estimates the painting area including hidden surfaces that are not actually painted in the field. To improve these computations, we propose an approach based on Adaptively-Sampled Distance Fields (ADFs) exploiting the relationship between object areas and Constructive Solid Geometry (CSG) operations. Tests with synthetic models demonstrate that our technique achieves an accuracy of 99%. In real-world 3D CAD models, we were able to reduce the estimated area by 38% when compared to the naïve calculations. These result in significant cost savings in material provision and workforce required for maintaining these facilities.