SolveSpace

The angle-bracket tutorial shows how a constrained sketch becomes a solid. Draw a closed profile with Line Segment, anchor a corner to the origin, and add horizontal, parallel, perpendicular and equal-length constraints. Tangent Arc at Point rounds the inner corner. New Group > Extrude creates the solid; the Property Browser switches it from one-sided to two-sided.

A second constrained sketch forms the gusset. Equal Length ties its thickness to the bracket. For mounting holes, draw two circles on a new workplane, give them equal radii and symmetric centres, extrude them to the opposite face, then set the extrusion's combination to difference. Revising an earlier group propagates through the later features. Dragging a partially constrained sketch can produce an unexpected solution; Undo restores the earlier state.

Export depends on the geometry. STL and OBJ use the active group's triangle mesh. STEP requires NURBS surfaces and declares millimetre units. The export chord tolerance controls how closely a mesh approximates curves, but the maximum-segment setting can still cap its detail. A 3D wireframe contains lines and curves without solid surfaces.

SolveSpace is distributed under GPL version 3 or later. Keep its native model when dimensions or constraints need further editing; exported geometry serves the downstream handoff.