Bumpy Glass material

A bumpy reflective refractive material using ray tracing.

See also: Materials , Reflect , Refract , How to use caustics

This material can be used for water as well as glass.

Note

This material must have an Opacity (Of) of 1 for refractions to work correctly. The Alpha (Af) maybe be changed to suit compositing needs.

Parameters

Glass

Attenuation Density

This is the density of the material. A uniform density is assumed. If this value is greater than 0, the opacity falloff is calculated based on this density and the square of the distance the ray travels inside a refractive material. The larger this value, the higher the density of the material and the more opaque it will appear. Attenuation is only applied when the surface normal and the refracted ray point in opposing directions.

Attenuation Color

This color tints the attenuated opacity.

Lighting Effects

Shadows

Shadow Color

This value is used to tint the color of the shadow cast by the glass.

Caustics

Do Faux Caustics

If the box is checked, a slight trick is played on the shadow value to give a caustic effect.

If using PBR, turn this off, as PBR will automatically generate correct caustics.

Minimum Shadow Intensity

This value is the minimum value of the shadow when Faux Caustics are turned on. These values should be changed to suit the thickness of the object and the implied transparency of the material.

Maximum Shadow Intensity

This value is the maximum value of the shadow when Faux Caustics are turned on. These values should be changed to suit the thickness of the object and the implied transparency of the material.

Specular

Specular Intensity	A multiplier for the specular contribution to the material.
Specular Color	The specular highlight color.
Specular U Roughness	This value controls the size or spread of the specular highlight. If Anisotropic is selected, this value controls the specular highlight in only the U direction.
Specular V Roughness	If Anisotropic is selected, this value controls the specular highlight in only the V direction. It is ignored with any other specular function.
Specular Sharpness	This value controls the sharpness of the edge of the specular highlight. It is used only if Glossy specular is selected.
Specular Type	A selector for the specular function. Glossy is typically used to get the sharp highlight common to glassy surfaces. See specular for more information.

Reflections

Reflection Intensity	A multiplier to dim or brighten the reflections.
Reflection Tint	This is a tint color for reflections.

Ray Trace

Refraction Intensity	This is a multiplier to dim or brighten the refractions.
Refraction Tint	This is a tint color for the refractions. This is color is also known as the transmission color. Use this to color the glass or water. A little color goes a long way, so something very pale (desaturated) might be be best to start.
Index of Refraction	This value is the ratio of the speed of light in one medium, such as air, to that of another medium. This determines how much the ray bends as it passes from one material into another. Higher values tend to "push" the reflections towards the edges. The refractions are in the center. The expected value is Eta, which is 1/the index of refraction.
Jitter Amount	This is a value between 0, no jitter and 1, maximum jitter. It controls how randomly the samples are distributed.
Ray Bias	This is typically a small number used to help solve self-intersection issues.
Cone Angle	This parameter is used by the PBR renderer. This is size of the cone (in degrees) over which samples are distributed. Any number greater than zero, will blur the refractions.
Area Samples	The number samples to calculate. The more samples, the better the quality, the slower the render.

Environment Map

Environment Map	If there is the path to a texture here and ray trace is turned off, then this map is used to calculate the reflection contribution. If ray trace is on and there is a texture, then the texture color is returned, when the ray does not hit anything. Without a texture here, the Background Color is returned when the ray misses. It is recommended to have a texture path in this slot. The background image as a texture is a good choice to start.
Transform Space	The reflection ray used to do the look up in the map is transformed into this space. See envmap for more information.
Background Color	This color is returned when the ray does not hit anything and there is no environment map specified.

Displacement

Displacement Scale	Controls the overall scale of the pits.
Frequency	The frequency of the pits. Larger values give more, but smaller pits. See cavities for more information.
Amplitude	This is the maximum value for the pits. This is then multiplied by the Overall Scale. See cavities for more information.
Chip Amount	This value is very touchy. It affects the space between the the pits. See cavities for more information.

Properties

Displacement Bound	Usually tying this value to the displacement Overall Scale should work well. However making the displacement bounds as small as possible, without causing “rips” in the render, can lower render times. See render properties for more information.
Displacement Space	Performs various space conversions of 3D positional data for UV shading purposes.
Reflect Limit	This limits the number of bounces for a reflection ray. Larger numbers equal longer rendering time and may not improve the images. See render properties for more information.
Refract Limit	This limits the number of bounces for a reflection ray. Larger numbers equal longer rendering time and may not improve the images. See render properties for more information.