Free online OFF to SCAD converter

What the OFF format is

OFF, or Object File Format, is a plain-text format for polygonal surfaces. Its header is followed by counts for vertices, faces, and edges, then vertex coordinates and face definitions that reference vertices by zero-based index.

OFF is used by Geomview, MeshLab, CGAL-based programs, academic geometry software, and mesh datasets. A face can contain three or more vertex indices, so the file may store triangles, quadrilaterals, or general polygons. Standard OFF files usually store geometry only; optional per-vertex or per-face color values are not reliably preserved by converters.

What the SCAD format is

SCAD is OpenSCAD's source-code format. It describes geometry through primitives such as cube() and sphere(), Boolean operations such as union() and difference(), transformations, variables, modules, and mesh literals such as polyhedron().

An OFF mesh is normally represented in SCAD as one polyhedron(points = [...], faces = [...]); statement. This makes the result editable as source code and combinable with other OpenSCAD objects, but it does not reconstruct the original parametric design: the converted file remains a fixed list of points and faces.

How to actually convert OFF to SCAD

For a quick conversion without installing software, use the OFF-to-SCAD converter on 101convert.com: upload the .off file, choose SCAD as the output format, run the conversion, and download the resulting .scad file.

For local or repeatable conversion, use a short Python script that translates OFF records into OpenSCAD's polyhedron() syntax:

#!/usr/bin/env python3
import sys

src, dst = sys.argv[1], sys.argv[2]
with open(src, encoding='utf-8') as f:
    tokens = []
    for line in f:
        line = line.split('#', 1)[0]
        tokens.extend(line.split())

if not tokens or tokens[0].upper() != 'OFF':
    raise ValueError('The input is not a standard OFF file')

nv, nf, _ = map(int, tokens[1:4])
pos = 4
points = []
for _ in range(nv):
    points.append([float(tokens[pos]), float(tokens[pos + 1]), float(tokens[pos + 2])])
    pos += 3

faces = []
for _ in range(nf):
    count = int(tokens[pos])
    pos += 1
    faces.append([int(tokens[pos + i]) for i in range(count)])
    pos += count

with open(dst, 'w', encoding='utf-8') as f:
    f.write('// Converted from OFF\npolyhedron(\n')
    f.write('  points = [\n')
    for i, p in enumerate(points):
        comma = ',' if i + 1 < len(points) else ''
        f.write('    [%r, %r, %r]%s\n' % (p[0], p[1], p[2], comma))
    f.write('  ],\n  faces = [\n')
    for i, face in enumerate(faces):
        comma = ',' if i + 1 < len(faces) else ''
        f.write('    [%s]%s\n' % (', '.join(map(str, face)), comma))
    f.write('  ]\n);\n')

Save it as off_to_scad.py, then run:

python3 off_to_scad.py model.off model.scad

Open the result in OpenSCAD and use Design → Preview or press F5. Use Design → Render or press F6 to validate the final solid before exporting it.

Quality and compatibility limitations

OFF does not normally define units, so the coordinates are imported without scaling. If the source uses millimetres, inches, or another unit system, apply an explicit factor in OpenSCAD, for example scale(25.4) { polyhedron(...); }.

The converter preserves vertex coordinates and face indices but generally discards colors, material data, texture coordinates, normals, comments, and other non-geometric attributes. Face winding must be consistent: reversed faces can produce incorrect normals or OpenSCAD warnings such as non-manifold geometry.

Non-planar polygons, self-intersections, duplicate vertices, holes, and non-manifold edges may fail during rendering. Repair or triangulate the mesh in MeshLab before conversion if OpenSCAD reports invalid faces. Triangulation improves compatibility but can change how a non-planar polygon is interpreted.