It's an accurate (with fillets and holes) 3D model of the Elegoo Neptune 3 and 4 (Pro/Plus/Max) build plate to be used as a custom background in PrusaSlicer, SuperSlicer or Cura.

I've added an embossed Elegoo-logo for a slightly refined look.

PrusaSlicer/SuperSlicer

You will find the build plate settings under:

"Printer Settings" → "General" → "Bed shape:" → "Set..."

The build plate model indended to be used with background images provided as SVG and AI files (main grid lines are exactly 40 mm and the secondary grid lines are 20 mm apart).

Cura

Copy elegoo_neptune_3_pro_cura.3mf or elegoo_neptune_3_pro_cura.stl to:

C:\Program Files\UltiMaker Cura 5.x.x\share\cura\resources\meshes

and change the “metadata” part of elegoo_neptune_3pro.def.json here:

C:\Program Files\UltiMaker Cura 5.x.x\share\cura\resources\definitions

as follows:

"metadata": { "author": "NARUTO", "visible": true, "platform": "elegoo_neptune_3_pro_cura.3mf", "platform_offset": [0, 0, 0], "quality_definition": "elegoo_base", "machine_extruder_trains":{"0": "elegoo_neptune2_extruder_0"} },

Commas are especially important!