Geometry

The geometry section defines how special surface effects are calculated relative to the underlying 3D geometry. These parameters control backface visibility, opacity thresholds, thin-film effects, and depth-based adjustments like opacity attenuation.

Parameters

Display Name	Name	Type	Default
Thin Walled	thin_walled	bool	false
Enable Opacity	enable_opacity	bool	false
Opacity	geometry_opacity	float	1.0
Opacity Threshold	geometry_opacity_threshold	float	0.0
Geometry Normal	geometry_normal	float3	state::normal()
Displacement	geometry_displacement	float3	0.0, 0.0, 0.0

Thin Walled

This parameter sets the surface as an infinitely thin double-sided shell with a refraction index of the surrounding medium, so refracted rays exit immediately instead of entering the medium.

Thin-walled is ideal for geometrically thin objects, like a sheet of paper, soap bubble, and leaves.

Note

“Dispersion” has no effects when Thin-Walled enabled.

Thin Walled: Disabled

Thin Walled: Enabled

Tip

When Thin-Walled is enabled, “subsurface” is represented as the diffuse transmission of the light through an infinitely thin shell, i.e., translucence.

Thin Walled: Disabled

Thin Walled: Enabled

Enable Opacity

Enables the use of opacity

Opacity

This parameter controls the travel of rays through the surface. At 0.0, the surface is invisible to the cameras, while at 1.0, it is completely opaque.

It can create render-time geometric detail on low-resolution and thin geometries.

Tip

Unlike transmission, renderers are optimized to use opacity to quickly skip over empty parts of a surface with a few operations.

Opacity: 0.75

Opacity: 0.5

Opacity: 0.25

Opacity: Texture

Opacity Threshold

This parameter controls the opacity threshold. At a value lower or equal to the opacity map, the surface renders completely transparent. At a value greater than the opacity, the surface renders fully opaque.

Geometry Normal

This parameter replaces the surface geometric normal with the one evaluated from a map. “Geometry Normal” has no effects on the coating layer.

Aluminum Foil

Beach Gravel

Displacement

This parameter sets the direction and distance of position modification of the surface.

Important

This feature is not supported yet.