Milling know-how

CNC nesting explained: how material optimization works

If you mill or laser several parts from one sheet, skipping nesting wastes real material: placing every part by hand costs time, and manual layouts are rarely the densest. Nesting does the puzzling automatically.

The classic route needs two tools for this: first a dedicated nesting program that computes the layout, then an export and a CAM program for the G-code. step2gcode combines both: the layout and the finished G-code are created in a single pass. Based on our research (as of July 2026), it is the only free-to-use browser tool that combines STEP import with integrated nesting.

Try nesting directly: arrange parts and download G-code →

How to do it in step2gcode

  1. Upload several files at once (DXF, SVG and STEP mixed) or open "Arrange multiple parts".
  2. Set the quantity per part.
  3. Specify sheet size, part spacing and margin.
  4. Let it arrange: step2gcode places the parts space-efficiently, with 90-degree rotation where useful.
  5. Check the result in the preview and download the G-code for all parts as one job.

Why combined beats the two-tool route

In short: because the intermediate export disappears, and with it the typical failure points. On the classic route, the nested layout travels to CAM as a new file, where scale, units or contour assignment can break, and every quantity change restarts the whole procedure.

In the combined pass the assignment survives: every part keeps its machining features (contours, pockets, holes), holding tabs and parameters apply to the whole job, and a changed quantity is one click instead of another export-import round.

The STEP specialty: nesting with real depths

Pure nesting tools work with flat outlines. step2gcode also nests STEP parts, and they bring their depth information along: pockets and holes are preserved per part and end up in the G-code. That way even parts with different machining features can be produced together on one sheet.

What the nesting can and cannot do

The layout uses real shape nesting with optional 90-degree rotation and adjustable spacing, not simple rectangle packing. There are still limits: if you want to squeeze out the last percent of material utilization with free rotation angles, dedicated nesting programs like Deepnest are the right choice, but then the G-code has to be generated separately again.