Learn/Drafting/2D Sketch Editor
Sketch on a Face (Auto-Projection)
Updated v2.3.7At a glance
- Start a sketch on a body face and its outline is projected in for you
- Face boundary plus coincident neighbour edges — deduped to one clean loop
- Associative: the projection follows the body as it changes
- Reserved, read-only Projection layer you can hide, recolor, export, or delete
When you start a sketch on a flat face of a solid body, JetCad3 projects that face's edges onto the new sketch automatically — so you have real geometry to snap and dimension against from the first click, instead of tracing the part by eye.
What lands on the sketch
The face's own boundary comes across, plus any edges of neighbouring faces that lie in the same plane — a hole breaking through the face, the edge of an adjacent step. Every shared edge is collapsed to a single loop, so you never get the doubled-up, endpoint-swapped ghost lines that make a projected outline a nightmare to clean up before a plasma or laser cut.
It stays linked to the part
The projection is associative: change the underlying body and the outline updates to match. Any dimension or constraint you attached to a projected edge moves with it rather than breaking. If the source face is ever removed entirely, the projection freezes at its last good shape and a repairable notice appears — nothing silently vanishes.
The Projection layer
Projected geometry lives on a reserved, read-only layer named Projection. You can't draw into it (its contents are derived from the body), but you have full control otherwise — hide it, recolor it, export it on its own, or delete it in one action. When you export a whole sketch to DXF or SVG, JetCad3 asks whether to include the Projection layer, so reference lines never sneak into a cut file by accident.
Turning it off
Auto-projection is on by default. Toggle it under Settings → Drafting → "Auto-project when sketching on a face."