Rendering Backends¶

Hakowan supports multiple rendering backends, allowing you to choose the renderer that best suits your needs. Currently, two backends are available: Mitsuba (default) and Blender.

Available Backends¶

Mitsuba Backend¶

The Mitsuba backend is the default renderer in Hakowan. It is based on the Mitsuba 3 physically-based rendering system, which provides high-quality, photorealistic rendering with advanced lighting and material models.

Advantages: - High-quality photorealistic rendering - Fast rendering with GPU acceleration - Support for advanced materials and lighting - Default backend, no additional configuration needed

Usage:

import hakowan as hkw

layer = hkw.layer("mesh.obj")
# Mitsuba is the default backend
hkw.render(layer, filename="output.exr")

# Or explicitly specify Mitsuba
hkw.render(layer, filename="output.exr", backend="mitsuba")

Blender Backend¶

The Blender backend uses Blender's rendering engine through the bpy Python API. This backend is useful if you want to leverage Blender's rendering capabilities or integrate Hakowan into a Blender-based workflow.

Advantages: - Integration with Blender ecosystem - Access to Blender's rendering features - Can save Blender scene files (.blend) for further editing

Requirements: - Blender's bpy module must be installed - Typically only available when running Python from within Blender or with a special bpy build

Usage:

import hakowan as hkw

layer = hkw.layer("mesh.obj")
# Explicitly specify Blender backend
hkw.render(layer, filename="output.png", backend="blender")

# Optionally save the Blender scene file
hkw.render(
    layer,
    filename="output.png",
    backend="blender",
    blend_file="scene.blend"
)

Backend Management¶

List Available Backends¶

You can query which backends are currently available:

import hakowan as hkw

backends = hkw.list_backends()
print(f"Available backends: {backends}")
# Output: Available backends: ['mitsuba', 'blender']

Note that the Blender backend will only appear if bpy is installed.

Set Default Backend¶

You can change the default backend for all subsequent render calls:

import hakowan as hkw

# Set Blender as the default backend
hkw.set_default_backend("blender")

# Now this will use Blender
layer = hkw.layer("mesh.obj")
hkw.render(layer, filename="output.png")

# You can still override per render call
hkw.render(layer, filename="output.exr", backend="mitsuba")

Backend-Specific Options¶

Different backends may support different options passed as keyword arguments to hkw.render().

Mitsuba Backend Options¶

# Save Mitsuba scene configuration to YAML
hkw.render(
    layer,
    filename="output.exr",
    backend="mitsuba",
    yaml_file="scene.yaml"
)

Blender Backend Options¶

# Save Blender scene file
hkw.render(
    layer,
    filename="output.png",
    backend="blender",
    blend_file="scene.blend"
)

Choosing a Backend¶

Use Mitsuba (default) when: - You want high-quality photorealistic rendering - You need fast rendering with GPU acceleration - You're creating publication-quality visualizations

Use Blender when: - You're already working in a Blender-based workflow - You want to further edit the scene in Blender - You need specific Blender features

Troubleshooting¶

If a backend is not available, you'll see an informational message when importing Hakowan:

Blender backend not available (bpy not installed)

To use the Blender backend, you need to install Blender and ensure the bpy module is available in your Python environment.