Geometry primitives
Sketches are the 2D foundation of parametric modeling. Draw lines, rectangles, circles, arcs, polygons, and splines on any plane or planar face, then turn the closed profile into a solid with extrude, revolve, sweep, or loft.
Every primitive you draw is fully editable. Change a dimension or drag a point and the profile — and everything built on it — updates.
- Lines, rectangles, circles, arcs, slots, polygons, and splines.
- Draw on the origin planes or on any flat face of an existing solid.
- Type a value mid-draw to set an exact dimension instead of eyeballing it.
Geometric and dimensional constraints
The constraint solver is what makes a sketch parametric instead of just a drawing. Geometric constraints capture design intent — horizontal, vertical, parallel, perpendicular, tangent, concentric, equal, symmetric — while dimensional constraints lock exact lengths, radii, and angles.
A fully constrained sketch has no free degrees of freedom: change one driving dimension and the whole profile updates predictably. This is the difference between a robust model and one that falls apart when you edit it.
- Geometric: horizontal, vertical, parallel, perpendicular, tangent, concentric, equal, symmetric, coincident.
- Dimensional: linear distance, radius, diameter, and angle.
- The solver colors under-constrained geometry so you can see what is still free to move.
Tip: Aim to fully constrain sketches you intend to reuse or share. Under-constrained sketches are fine for quick concepts but can shift unexpectedly when a parent feature changes.
Sketch on a face
You are not limited to the origin planes. Select any flat face of an existing solid and sketch directly on it to add bosses, cuts, holes, and pockets that reference real geometry.
Sketches placed on a face stay associated with that face, so the feature moves with the model as it evolves.
Constraint inference and snapping
As you draw, HelioCad infers likely constraints and snaps to meaningful references — endpoints, midpoints, face centers, quadrants, and intersections — so profiles come together cleanly without hunting for the right point.
Snapping speeds up accurate sketching, and inferred constraints are added automatically so your intent is captured as you go. You can always remove or override any constraint the solver added.
Ready to try it yourself?
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