About 3DS PBR Materials

It takes an RGB value in the range [0,1] as a constant or from a texture and applies it to the material. Make sure that a base color texture does not include any lighting effects like shadows or specular highlights, because these effects are simulated by the rendering algorithm.

A value of 0.0 denotes a nonmetallic or dielectric surface, a value of 1.0 is used for a metallic surface. Occasionally you may want to use values in between to linearly blend between the two models, for example for rusty metal.

Nonmetals are 0, metals are 1. This is a binary decision, a pure material can either be dielectric or metallic. Only if you want to layer, for example, dust onto metal, this parameter is between 0 and 1.

Metallic from 0 to 1

Smooth and polished surfaces have a low roughness value, rough surfaces have a high value. A perfect mirror has a value of 0.

Roughness from 0 to 1. Nonmetal top, metal bottom.

This allows you to add details like small bumps and dents without using more polygons. The normal direction is encoded as an RGB value in a texture, where the default normal [0,0,1] is mapped to the color [128,128,255].

Click then select the appropriate value: Bump Texture or Round Corners.

Some fabrics like velvet show a significant amount of rim lighting (or sheen), resulting from both forward and backward scattering. This comes from tiny fibers standing straight up on the surface, creating a bright effect when seen at grazing angles.

Defining this parameter to 1 means that flakes entirely cover the surface.

The higher the value, the more they deviate from it.

Commonly 0 or a small value, although any value between 0 and 1 is supported.

An opaque surface has a transparency of 0.0, a transparent surface like glass or water has a transparency of 1.0. Values in between blend between the two models and may occasionally be useful for hybrid surfaces like dirty glass.

Opaque surfaces are 0, transparent surfaces are 1. This is a binary decision, a pure material can either be opaque or transparent. Only if you want to layer, for example, dust onto glass, this parameter is between 0 and 1.

For textures in black and white, white is transparent and black is opaque.

• Either the geometry defines the boundary between the outside world and a volume, that is, the geometry encloses a volume. In this case, you must define Thin Walled to false and use the volume parameters to configure scattering inside the volume.
• Or the geometry defines an infinitely thin volume with surfaces on both sides. Thin Walled must be defined to true and the volume parameters (except Index of Refraction) do not have an effect.

This parameter has no effect if the material is not transparent.

Thin walled (left) and volumetric sphere (right).

Geometry (black line) defines the two-sided object with an infinitely thin volume inside. . Right: Geometry (black line) defines the boundary between outside and inside (gray box).

If the material is thin, that is, Thin Walled is activated, the volume is infinitely thin and, thus, the light is not refracted. However, the reflectivity is still computed from the index of refraction.

Index of Refraction 1 to 2.

Attenuation Distance has no effect on Thin Walled materials, as an infinitely thin surface does not absorb light.

Subsurface scattering (SSS) of light inside a volume. While traveling through the medium, light rays may not only be absorbed when hitting a particle, but also scattered into some direction, eventually leaving the surface at another point.

Simulating the scattering of light inside the material's volume, called subsurface scattering, gives visually rich and realistic results at the cost of expensive calculations. It is indispensable for simulating materials like milk, juice, honey, marble, and similar. Translucency can be computed much more efficiently, allowing for very accurate support in real-time rasterizers. In addition, translucency has the advantage that subsurface parameters can efficiently be textured by 2D surface textures.

It exposes a parameter "g" that determines whether light is scattered equally in all directions (g=0), whether forward scattering dominates (g > 0) or backward scattering dominates (g < 0).

0 means that the surface is opaque, 1 indicates the maximum translucency.

• Select Light Emittance to specify the brightness as luminous power (roughly: the power emitted by the light source; unit: lumens or lm).
• Select Light Power to specify the brightness as luminous power (roughly: the power emitted per surface area of the light source; unit: lux).

Illustration of the two emission modes.. Left: The emission of both spheres is 1 lux by specifying an Emission Value of 1 and defining Emission Mode to false. When directly looking at them, they appear equally bright, but the amount of energy they emit is significantly higher for the large sphere. Right: Emission is 1 lm for both spheres by specifying Emission Mode as true. They radiate the same amount of energy into the scene but they are differently bright when looking at them directly.

• When Energy Normalization is cleared, darker emission colors lead to darker emission even if hue and saturation are kept constant. The quantity of emitted light is determined by Emission Mode and the product of Emission Color and Emission Value. Example: Emission Color is 50% gray, Emission Value is defined to 1 and Emission Mode to luminous power. As a result, the light source emits colorless light at 0.5 lm.
• When Energy Normalization is activated, the quantity of emitted light is solely determined by the Emission Mode and the Emission Value. Emission Color only modifies the colorfulness of the light. Example: Emission Color is 50% gray, Emission Value is 1, and Emission Mode is defined to luminous power. As a result, the light source emits colorless light at 1 lm.

In both images, the emissive value of both spheres is 1 and emission quantity to luminous power. . The left sphere has a dark gray emission color, on the right sphere it is white. Without energy normalization (left) the left sphere is darker as emission color influences intensity. With energy normalization (right), they are equally bright as only emission color chromaticity is considered.

If you want pure diffuse materials, maybe for simple visualizations in engineering or high-performance preview renderings, you can define this parameter to 0 to completely disable the microfacet-based reflection component.

At grazing angles, the reflection still blends to white, and the parameter has not effect on metals.

This is useful, for example, for brushed metal, where the mirror-like microfacets on the surface are all oriented into the same direction, resulting in a long and narrow highlight. A value of 0 disables anisotropy, a value of 1 defines it to the maximum.

The direction of the microfacets is initially given by the texture coordinates of the mesh.

Given a highly tessellated mesh and a height/displacement map, vertices are displaced according to the values in the texture, creating the geometric detail not at modeling but at rendering time.

Click , and then use the Height parameter to define the appropriate value from 0 to 1.

Unlike the Height parameter, the Displacement parameter is not connected to a texture and can be interpolated to adjust the elevation effect across renderers.

You can also click to open a texture file from the database or from an external content through the Content Chooser.

A surface either has a cut (0) or not (1). This is a binary decision. If a surface has a hole, define the cut-out opacity to 0. If not, define it to 1. Values in-between can be used to smooth the edges. Use the Transparency parameter if the surface is semitransparent, for example for glass or water.

For textures in black and white, white is opaque and black is transparent.

Cut-out mask (left) applied to a sphere (right).

Note: Transparent regions are exactly 0, opaque regions are exactly 1. Other values are only used for anti-aliasing at edges.

It is important to distinguish between Transparency and Cut-Out Opacity.

Transparency is a view-dependent effect that blends between reflection and transmission based on a Fresnel term.

Cut-Out Opacity is not view-dependent. It makes the surface transparent after lighting computations have finished.

Transparency (top) and (inverted) Cut-Out Opacity (bottom) 0 to 1.

Note: While the sphere with cut-out completely vanishes, the transparent sphere still reflects light at grazing angles.