GemDiagram Docs

Import an Existing Design

If you have a cutting plan from another tool, GemDiagram can open it. Supported formats are .facet (GemDiagram's native format), .asc (ASCII gem data), .gem (Gem CAD), and .gcs (Gem Cut Studio).

How to import

Click the Import button in the top bar, select a file from your computer, and click Open. The design loads into the editor.

Note

If the imported file carries a refractive index that doesn't match a built-in material, GemDiagram keeps that value as a Custom RI and snaps the material dropdown to the closest match for the remaining optical data — so the exact imported RI is preserved and the stat tiles and reports still have a material to read from. See Choosing a Material for how this works.

File formats

.facet (GemDiagram native)

A compact binary format storing the full design: all tiers, angle/distance/ indices, material, girdle size, color, and render settings. This is what you get when you click Save.

.asc (ASCII gem data)

A plaintext format listing tiers in sequence. GemDiagram extracts the tier angles, distances, and indices, plus any refractive index specified in the file. Tier names and other metadata are preserved if the file includes them.

.gem (Gem CAD)

A binary format from GemCad (a legacy Mac/Windows cutting-design app). Stores tiers, indices, angles, and sometimes material RI. GemDiagram reads the geometry and snaps the material to the closest RI match if needed.

.gcs (Gem Cut Studio)

A newer variant of Gem CAD format, CSV-like structure. GemDiagram parses the tier table and any RI field.

After import

Once the design loads, you can:

  • Examine it: Rotate the 3D preview, inspect the Build panel and Diagrams.
  • Edit it: Adjust any tier's angle, distance, or indices. Change the material, color, or size.
  • Re-save it: Click Save to download as a .facet file, or use the Export menu to generate a new PDF diagram.

If the file imported with angles that look odd or a material that doesn't match your stone, you can manually correct the design in the Build panel or re-select the right material from the Material dropdown.

Tip

When you import a .gem/.gcs/.asc file, compare the imported material (shown in the Material dropdown) to the stone you're actually working with. If the RI doesn't match, change the dropdown to the correct material — the whole design will update its optical behavior to match. See Refractive Index & Dispersion for why this matters.

Coming from GemCAD or Gem Cut Studio?

If you're switching to GemDiagram from another tool, check our comparison pages:

Both pages show exactly what imports, what doesn't, and where GemDiagram adds workflow steps the other tools don't have.

Tip

Only have a PDF cutting report, not a .gem/.gcs file? See Import a Faceting Diagram PDF — a Pro feature that reconstructs a .facet design straight from the printed diagram.

Exporting

For a cutting-shop workflow, Export → PDF generates a detailed report with every tier's facet count, angles, distances, and proportions — ready to print or email to a cutter.