How to Convert 3D Models with Aspose.3D FOSS

Problem

Developers working with 3D assets in Python often need to convert models between formats; for example from OBJ to glTF binary, or from STL to 3MF. Aspose.3D handles this with two calls: Scene.from_file() to load the source file and scene.save() to write the output in the desired format.

Prerequisites

Python 3.7 or later
Install via pip: pip install aspose-3d-foss

from aspose.threed import Scene, FileFormat

Conversion Steps

Step 1: Load the Source File

Use Scene.from_file() to load any supported input format. The method detects the format from the file extension automatically.

from aspose.threed import Scene

scene = Scene.from_file("model.obj")

To pass load options (for example to control coordinate system flipping when loading OBJ), provide an options object as the second argument:

from aspose.threed import Scene
from aspose.threed.formats import ObjLoadOptions

options = ObjLoadOptions()
options.flip_coordinate_system = False

scene = Scene.from_file("model.obj", options)

Step 2: Save to the Target Format

Call scene.save() with the output file path. The format is inferred from the file extension, or you can pass a FileFormat constant explicitly for unambiguous control.

from aspose.threed import FileFormat

# Save as binary glTF (.glb): compact and widely supported
scene.save("output.glb", FileFormat.GLTF2_BINARY)

# Save as STL
scene.save("output.stl")

# Save as 3MF
scene.save("output.3mf")

Step 3: Use Save Options for Fine-Grained Control

For glTF output you can use GltfSaveOptions to control binary mode and other settings:

from aspose.threed.formats import GltfSaveOptions

opts = GltfSaveOptions()
opts.binary_mode = True
scene.save("output.glb", opts)

Code Example

Complete example: load an OBJ file and convert it to binary glTF.

from aspose.threed import Scene, FileFormat

# Step 1: load the source model
scene = Scene.from_file("model.obj")

# Step 2: save to binary glTF
scene.save("model.glb", FileFormat.GLTF2_BINARY)

print("Conversion complete: model.obj -> model.glb")

Supported Formats

Aspose.3D supports conversion between multiple 3D formats.

Format	Extension	Notes
Wavefront OBJ	.obj	Load and save supported
glTF 2.0 binary	.glb	Compact binary format; use `FileFormat.GLTF2_BINARY`
glTF 2.0 JSON	.gltf	Use `FileFormat.GLTF2`
Microsoft 3MF	.3mf	Load and save supported
STL	.stl	Load and save supported
FBX	.fbx	Load supported for basic geometry (limited); see FBX note below

Note on FBX: Aspose.3D FOSS has limited FBX support. Loading basic geometry from FBX files works in most cases, but writing to FBX is not fully supported. Use glTF or OBJ as the preferred output format.