Cross-Sectional Curve-based Elevation Construction and Editing for 2D-Floor-Plan Designers

   Precise elevation design on an aerially reconstructed terrain can ensure an appropriate structural slope for good driving conditions and dovetail the design with real world. Traditional planners are used to drawing curves for 2D floor design, but there is no 2D cross-sectional curve-based mechanism to design a 3D terrain. Therefore, this work aims to bridge the gap between the intuitive 2D curve-based design practice and precise 3D terrain construction. Since floor planners generally refer to 2D cross sections for elevations and are more familiar with curve manipulation instead of 3D mesh editing, this work proposes an elevation modeling tool based on editing the 2D cross section of user-drawn ground-projected curves. To follow intuitive 2D curve-designed practices and achieve precise 3D altitude control, our system lets users freely draw curves on the ground as 3D constrained parametric curves and constructs ground-projected plane for 2D cross-sectional manipulation. Then, we diffuse the parametric elevations to their surroundings and construct its height field by solving the corresponding differential equation. Finally, we utilize remeshing to ensure patch boundaries precisely align with the constrained curves. Thus, our system can relieve the brush-style and feature-based limitations as well as the NURBS-based knot-tuning difficulty and complexity in precise elevation and variation control and accurate boundary-to-constrained-curve alignment. Numerical experiments and a usability study of naives and experts demonstrate our intuitiveness and effectiveness over state-of-the-art methods and verify our ability to intimate traditional 2D curve-based design practice.