slopsurface

Word

directed smooth colour

fill lines shade opacity contour curves side curves grid curve res smooth curves RP² Klein mesh smooth

Draw: click inside the polygon to add points, click a side to continue on the identified side, click a vertex to end an edge there, click the first point to close a curve. Right-click / Enter finishes an open curve. Select mode: drag vertices and waypoints, double-click to label, Del to delete. 3D: drag to rotate, wheel to zoom, right-drag to pan.

scale show a⁻¹ labels scale style hidden lines fill surface mesh edges