Why does importing a big STL fail with an "out of memory" or "insufficient memory" error?

What the message means

The import ran out of working memory while turning the mesh into a component. The software stores 3D shapes as a grid of height pixels sized by the job, so memory use depends on three things at once: how many triangles the mesh has, how physically large the model is when it lands, and how fine the job's modeling resolution is. Any one of them can push an import over the edge.

Usual causes on the public user forum, most likely first:

1. A units mix-up. A model drawn in millimeters brought in as inches arrives about 25 times too large in every direction, and the program tries to build something enormous.
2. A very dense mesh, typically a 3D scan or a sculpt exported at full detail.
3. The job was created at one of the higher resolution settings on a large material size.
4. A very old 32-bit version of the program, which could not use much memory no matter how much the PC had. Versions from 8 onward are 64-bit.

How to fix it

1. Start the import again and look at the size shown on the orientation form before you accept it. If the numbers are absurd, switch the model units (mm or inches) to match how the file was made.
2. Scale the model on that form to the size you actually plan to cut, rather than importing huge and shrinking later.
3. If it still fails, thin the mesh first. Forum users use the free program MeshLab to simplify the triangle count, and one long-standing suggestion there is that roughly 300,000 triangles keeps plenty of detail for a relief carving.
4. Create the job at the standard resolution with a material size only slightly larger than the model, then import.
5. Close other heavy programs, restart the software and try again.

How to confirm it is fixed

The component appears in the Component Tree, the 3D view rotates smoothly, and the model's reported size matches what you expect.

Pro tips

• A carving cannot show detail finer than your finishing bit, so a multi-million-triangle mesh buys nothing at the machine.
• STEP files are a separate problem: they are not a supported format at all (see the entry on 3D files that will not open).
• For orientation, scaling and zero plane choices after a successful import, see the entries on importing STL models.