Lofted Arc Profile Body

Create a solid 3D model in millimeters and export as STEP. Use a coordinate system where Z is vertical. Build 5 closed sketch profiles on horizontal planes at Z = 0, 4, 8, 12, and 15.56 mm. Every profile has the same construction: starting at origin (0,0), draw a straight line along the X-axis to point A, then a three-point arc from A through M to B, then a straight line from B back to the origin along the Y-axis. The profile corner at the origin is exactly 90 degrees and the two straight edges lie exactly on the X and Y axes in every profile. Profile at Z=0: A=(12.54, 0), M=(8.00, 6.89), B=(0, 10.33). Profile at Z=4: A=(12.77, 0), M=(7.50, 8.33), B=(0, 11.47). Profile at Z=8: A=(12.28, 0), M=(7.12, 8.86), B=(0, 12.30). Profile at Z=12: A=(11.14, 0), M=(6.52, 8.26), B=(0, 12.02). Profile at Z=15.56: A=(9.57, 0), M=(6.07, 5.83), B=(0, 9.89). Loft smoothly through all 5 profiles in order to form a single solid, with flat planar caps at Z=0 and Z=15.56. Critical: the two side faces formed by the straight profile edges (the XZ-plane face and the YZ-plane face) must remain exactly planar and vertical along the full height — do not smooth or blend them. Only the arc side lofts as a smooth freeform surface. Output one watertight solid body, STEP AP214.

Parameters

Every value above is a live dimension. Open a model like this in the editor and each one becomes a slider you can drag before exporting.