3D Sketches
A 3D sketch holds lines, arcs, circles and splines in space rather than on one plane. Use it for frames (see the Fast Structure chapter), pipe, duct and wiring routes, and sweep paths.
Starting and ending a 3D sketch
Click 3D Sketch on the Sketch tab or the Fast Structure tab (or Insert ▸ 3D Sketch). The sketch opens empty with the Line tool ready; there is no plane to pick. While it is open the 3D Sketch button stays highlighted and the first button becomes Exit 3D Sketch. Tools that only work in 2D sketches are greyed out. Ctrl+Z / Ctrl+Y undo and redo inside the sketch.
Drawing in space
- Click points to draw lines. A line snaps along X, Y or Z from the last point whenever the mouse moves along that direction on screen, in any view. A dashed line shows it and an Along X/Y/Z relation is added. Hold Ctrl or Shift to draw freely.
- Away from the axes, lines follow the drawing plane through the last point. Tab cycles XY → YZ → ZX; the plane's name shows at the cursor.
- Ctrl+click a plane or flat face, or click a plane in the tree, to draw on it. Points placed there get an On Plane relation. Tab or Esc goes back to XY / YZ / ZX.
- Points snap, in this order, to the sketch's own points, to line midpoints (Midpoint relation), to a point along a line (On Line relation), to the origin and model vertices, along X/Y/Z, then to the drawing plane.
- The Next Point box in the Property panel takes exact offsets, for example
0, 0, 250. - A selected point shows its X, Y and Z; type new values to move it. A selected line shows its length, ΔX/ΔY/ΔZ and end points; an arc its radius, angle and length.
3D sketch tools
| Tool | Key | How it works |
|---|---|---|
| Line | L | As above |
| Centerline | Construction lines that shape the sketch (for example a frame envelope) but make no curve | |
| Point | A lone point | |
| Circle, Centerpoint Arc, 3 Point Arc, Polygon | C, A, P | Drawn on the active drawing plane through the first click. Tab changes the plane before or between clicks. A polygon stays regular. |
| Tangent Arc | Click the free end of a line, arc or spline, then where the arc ends. Keep clicking for more arcs; Esc ends. | |
| Spline | N | Click the points it runs through; double-click or Enter ends it, clicking the first point closes it. A Tangent relation with a line at an end makes it leave the line smoothly. |
| Sketch Fillet / Sketch Chamfer | Click a corner where two lines meet. The sharp corner stays as a point on both lines, so lengths measured to it keep their meaning. | |
| Trim | T | Click the piece to remove, up to where other entities cross or touch it |
| Project Edges | E | Click model edges to bring them in, linked to the model (see below) |
| Dimension | D | Length, distance between points, angle between lines, arc radius, circle diameter. While placing a length, Tab cycles true length → ΔX → ΔY → ΔZ. |
| Construction Geometry | Q | Toggles the selected lines to or from construction |
| Delete | Del | Deletes the selection |
Move / Copy / Rotate: drag a selected line, arc or circle to move the selection (it snaps along X, Y and Z), or type ΔX/ΔY/ΔZ and click Move or Copy, or rotate about X, Y, Z or the drawing plane's normal with Rotate or Copy Rotated. Copies keep the relations among the copied geometry. Fixed and projected geometry stays put.
Relations in 3D
Along X/Y/Z, Parallel, Perpendicular, Collinear, Equal Length, Equal Radius, Tangent, Midpoint, On Line, Parallel to XY / YZ / ZX, On XY / YZ / ZX plane, On Plane, Regular Polygon, Fix and Merge (coincident). A solver keeps everything held and reports Fully defined or the degrees of freedom left. A relation or dimension that conflicts is refused with a message.
Projected edges in 3D
Project Edges brings model edges into the 3D sketch: lines stay lines, circular edges become arcs or circles and other curves become splines, with shared corner points. The geometry (purple) stays linked to the model: when the part changes, it follows the edges, and lines and dimensions attached to it follow too. Unlink from the Model in the Property panel makes it ordinary geometry.
Curves from a 3D sketch
Each connected run of lines, arcs and splines is one curve; a T-junction splits it into separate runs. A run can be used as straight segments with an optional bend radius at the corners (pipe and duct routes) or as a smooth spline, and can be closed into a loop. Sweep, Swept Surface, Lofted Surface, Curve Driven Pattern and Structural Member use 3D sketches.