Convert STL to DXF
An STL is a surface in three dimensions and a DXF is a flat drawing, so nothing converts one to the other whole. What this does is cut the model at a plane you choose and keep the outline where the plane meets it.
Measure, transform and cut an STL model. Your file stays in your browser.
What this keeps and what it drops
Kept
- The true outline where the plane meets the model, at its real size
- The model position, so the drawing sits where the section does
- The unit when the file states one, and no unit when it does not
Dropped
- Everything off the plane, which is most of the model
- Curvature, which the mesh already replaced with flat triangles
- Colour, materials and any structure an STL never carried
You choose the plane, so there is no single result to measure. What is fixed is what the tool refuses, and it refuses rather than dropping quietly.
Why there is no straight conversion
A DXF holds lines and arcs on a flat sheet. An STL holds triangles in space. Any tool that offers to turn one into the other has quietly picked a view for you, and picked wrong often enough that the drawing measures nothing you can use.
So this asks you the question instead. Pick an axis, pick a coordinate on it, and you get the outline where that plane passes through the model. On a printed bracket, a section through the boss gives you the hole and the wall around it, at the size they really are.
What comes out
Every triangle the plane crosses contributes one straight segment, and those segments are the drawing. They land on a single layer named Section, positioned where they sit on the model rather than moved to the origin.
The DXF is written and then read back and checked before it downloads, the same as every other DXF this site writes.
What it will not do
The plane has to pass through the model. A plane resting exactly on a face grazes it, and the outline you would get is the face rather than a section, so that is refused.
An STL usually states no unit, and the drawing says so rather than inventing one. Open the result in the DXF workspace and assign the unit you know the part is in; every measurement follows from that one choice. When the file did state a unit, the drawing carries it through.
Curves come out as straight segments, because that is what the triangles are. A cylinder sectioned across gives you a polygon, not a circle. If you want a solid rather than an outline, the same plane makes a capped cut in the STL editor.
Limits
The section accepts STL models up to 25 MiB and stops at 20,000 segments. The plane must lie strictly inside the model. Curved surfaces come out as straight segments, one per triangle, because the mesh has no curves left in it. Nothing recovers the original CAD geometry from a mesh.