Project geometry & construction lines

Aligned with the official sketching guide (Construction, Project). Practical steps for the active sketch; checked 26 October 2026.

Construction (`X`)

Construction turns sketch curves into reference geometry. They guide dimensions and constraints but do not form profiles for extrude, revolve and similar features.

Press X (or use the Construction control) while a draw tool is active to change the line type without ending the tool or losing picks.
With curves already selected, Construction flips those curves between normal and construction.
The Sketch Palette’s Construction Geometries option can hide construction curves while you work. Hidden construction curves cannot be picked. The option is per sketch and is saved with the design. Centerlines keep showing; projected geometry that carries the construction line type answers to Projected Geometries instead.

Typical uses: centre crosses, diameter helpers, symmetry axes, and layout lines you do not want in the solid profile.

Project (`P`)

Project brings geometry from the model (or from another sketch) into the active sketch as linked curves or points that follow later changes to the source.

Enter or create a sketch on the plane you need.
Select the sources you want: visible curves or points from another sketch, model edges, faces, vertices or bodies, or axes and planes.
Press P (or run Project). The whole supported selection is projected in one undo step.

Sketching on a face projects that face’s edges automatically. A projected edge stays tied to the edge you picked; if that edge disappears later, the projection keeps its last shape and the sketch reports that it was lost. An empty or mixed selection that Project cannot take starts ordinary picking instead so you can correct it.

Intersect is the related tool that brings model intersections into the sketch; see the same official page for details.

Constraints that take model edges or vertices

You do not always need a separate Project step first. For Coincident, Tangent, Equal, Parallel, Perpendicular, MidPoint (point and line, or two lines’ midpoints), Concentric, Collinear and Symmetry, any of the usual sketch arguments may instead be a model edge {edge: [x,y,z], body?} or vertex {vertex: [x,y,z], body?}. SolidCraft projects that into the sketch first; the projection is listed in the command’s created result. Handy for agents and scripts via MCP — see MCP tools. Source: docs.solidcraft.io print (constraint parameters).

Related requests this page does not cover

These come up often and are not documented as shipping features here — treat them as product gaps and track them on GitHub Issues if you need them:

Paste stacked on the original (paste-in-place)
Corel-style Ctrl+D repeat with a remembered offset
Wireframe or half-section view modes
Shared construction lines that span multiple sketches without Project

Try it

Practice in the web editor: sketch on a face to see auto-projected edges, toggle Construction with X, then Project an edge from a body into a second sketch. Official reference: Sketching and constraints.