Diffuse - this is the diffuse color of the
material. Note the actual diffuse color of the surface also depends on the
reflection and refraction colors. See the Energy
preservation parameter below.
Roughness - this parameter can be used to
simulate rough surfaces or surfaces covered with dust (for example, skin, or
the surface of the Moon).
Example
Reflect - reflection color. Note that the
reflection color dims the diffuse surface color based on the
Energy preservation option.
Example
Fresnel reflections - checking this option
makes the reflection strength dependent on the viewing angle of the surface.
Some materials in nature (glass etc) reflect light in this manner. Note that
the Fresnel effect depends on the index of refraction as well.
Example
Fresnel IOR - the IOR to use when
calculating Fresnel reflections. Normally this is locked to the
Refraction IOR parameter, but you can unlock
it for finer control.
Highlight glossiness - this determines the
shape of the highlight on the material. Normally this parameter is locked to
the Reflection glossiness value in order to
produce physically accurate results.
Reflection glossiness - controls the
sharpness of reflections. A value of 1.0 means
perfect mirror-like reflection; lower values produce blurry or glossy
reflections. Use the Subdivs parameter below
to control the quality of glossy reflections.
Example
Subdivs - controls the quality of glossy
reflections. Lower values will render faster, but the result will be more
noisy. Higher values take longer, but produce smoother results.
Use interpolation - V-Ray can use a
caching scheme similar to the irradiance map to speed up rendering of glossy
reflections. Check this option to turn caching on. See the
Reflection interpolation section for more
details.
Max depth - the number of times a ray can
be reflected. Scenes with lots of reflective and refractive surfaces may
require higher values to look right.
Exit color - if a ray has reached its
maximum reflection depth, this color will be returned without tracing the
ray further.
Refract - refraction color. Note that the
actual refraction color depends on the reflection color as well. See the
Energy preservation parameter below.
Example
IOR - index of refraction for the
material, which describes the way light bends when crossing the material
surface. A value of 1.0 means the light will not change direction.
Example
Glossiness - controls the sharpness of
refractions. A value of 1.0 means perfect
glass-like refraction; lower values produce blurry or glossy reractions. Use
the Subdivs parameter below to control the
quality of glossy refractions.
Example
Subdivs - controls the quality of glossy
refractions. Lower values will render faster, but the result will be more
noisy. Higher values take longer, but produce smoother results. This
parameter also controls the quality of the translucent effect, if on (see
below).
Use interpolation - V-Ray can use a
caching scheme similar to the irradiance map to speed up rendering of glossy
refractions and translucency. Check this option to turn caching on. See the
Refraction interpolation section for more
details.
Max depth - the number of times a ray can
be refracted. Scenes with lots of refractive and reflective surfaces may
require higher values to look right.
Example
Exit color - if this is on, and a ray has
reached the maximum refraction depth, the ray will be terminated and the
exit color returned. When this is off, the ray will not be refracted, but
will be continued without changes.
Example
Fog color - the attenuation of light as it
passes through the material. This option allows to simulate the fact that
thick objects look less transparent than thin objects. Note that the effect
of the fog color depends on the absolute size of the objects and is
therefore scene-dependent. The fog color also determines the look of the
object when using translucency.
Example
Fog multiplier - the strength of the fog
effect. Smaller values reduce the effect of the fog, making the material
more transparent. Larger values increase the fog effect, making the material
more opaque. In more precise terms, this is the inverse of the distance at
which a ray inside the object is attenuated with am amount equal to the
Fog color.
Example
Fog bias - this parameter allows to change
the way the fog color is applied; by adjusting this parameter you can make
thin parts of the object to appear more transparent than normal, or less
transparent than normal.
Affect shadows - this will cause the
material to cast transparent shadows, depending on the refraction color and
the fog color. This only works with V-Ray shadows and lights.
Affect alpha - this will cause the
material to transmit the alpha of the refracted objects, instead of
displaying an opaque alpha. Note that currently this works only with clear
(non-glossy) refractions.
Type - selects the algorithm for
calculating translucency (also called sub-surface scattering). Note that
refraction must be enabled for this effect to be visible. Currently only
single-bounce scattering is supported. The possible values are:
None - no translucency is calculated for
the material;
Hard (wax) model - this model is
specifically suited for hard materials like marble;
Soft (water) model - this model is mostly
for compatibility with older V-Ray versions (1.09.x);
Hybrid model - this is the most realistic
sss model and is suitable for simulating skin, milk, fruit juice and
other translucent materials.
Back-side color - normally the color of
the sub-surface scattering effect depends on the Fog color; this parameter
allows you to additionally tint the SSS effect.
Thickness - this limits the rays that will
be traced below the surface. This is useful if you do not want or don't need
to trace the whole sub-surface volume.
Light multiplier - a multiplier for the
translucent effect.
Scatter coefficient - the amount of
scattering inside the object. 0.0 means rays will
be scattered in all directions; 1.0 means a ray
cannot change its direction inside the sub-surface volume.
Forward/backward coefficient - controls
the direction of scattering for a ray. 0.0 means
a ray can only go forward (away from the surface, inside the object);
0.5 means that a ray has an equal chance of going
forward or backward; 1.0 means a ray will be
scattered backward (towards the surface, to the outside of the object).
The BRDF parameters determine the type of the highlights and glossy
reflections for the material. There parameters have an effect only if the
reflection color is different from black and reflection glossiness is
different than 1.0.
Type - this determines the type of BRDF
(the shape of the highlight): Example
Phong - Phong highlight/reflections
Blinn - Blinn highlight/reflections
Ward - Ward highlight/reflections
Anisotropy - determines the shape of the
highlight. A value of 0.0 means isotropic highlights. Negative and positive
values simulate "brushed" surfaces.
Example
Rotation - determines the orientation of
the anisotropic effect in degrees (rotation in degrees). Different brushed
surfaces can be simulated by using a texture map for the anisotropy rotation
parameter.
Example
Local axis - controls how the direction
for the anisotropic effect is chosen:
Local axis - the direction is based on the
selected local object axis.
Map channel - the direction is based on
the selected mapping channel.
Trace reflections - if this is
off, reflections will not be traced, even if the
reflection color is greater than black. You can turn this off to produce
only hilights. Note that when this is off, the diffuse color will not be
dimmed by the reflection color, as would happen normally.
Trace refractions - if this is
off, refractions will not traced, even if the
refraction color is greater than black.
Cutoff - this is a threshold below which
reflections/refractions will not be traced. V-Ray tries to estimate the
contribution of reflections/refractions to the image, and if it is below
this threshold, these effects are not computed. Do not set this to 0.0 as it
may cause excessively long render times in some cases.
Environment priority - this specifies how
to determine the environment to use if a reflected or refracted ray goes
through several materials each of which has an environment override.
Double-sided - if this is true, V-Ray will
flip the normal for back-facing surfaces with this material. Otherwise, the
lighting on the "outer" side of the material will be computed always. You
can use this to achieve a fake translucent effect for thin objects like
paper.
Reflect on back side - if this is true,
reflections will be computed for back-facing surfaces too. Note that this
affects total internal reflections too (when refractions are computed).
Use irradiance map - if this is true, the
irradiance map will be used to approximate diffuse indirect illumination for
the material. If this is off, brute force GI will be used. You can use this
for objects in the scene which have small details and are not approximated
very well by the irradiance map.
Treat glossy rays as GI rays - this
specifies on what occasions glossy rays will be treated as GI rays:
Never - glossy rays are never treated as
GI rays.
Only for GI rays - glossy rays will be
treated as GI rays only when GI is being evaluated. This can speed up
rendering of scenes with glossy reflections and is the default.
Always - glossy rays are always treated as
GI rays. A side effect is that the Secondary GI engine will be used for
glossy rays. For example, if the primary engine is irradiance map, and
the secondary is light cache, the glossy rays will use the light cache
(which is a lot faster).
Energy preservation mode - determines how
the diffuse, reflection and refraction color affect each other. V-Ray tries
to keep the total amount of light reflected off a surface to be less that or
equal to the light falling on the surface (as this happens in the real
life). For this purpose, the following rule is applied: the reflection level
dims the diffuse and refraction levels (a pure white reflection will remove
any diffuse and refraction effects), and the refraction level dims the
diffuse level (a pure white refraction color will remove any diffuse
effects). This parameter determines whether the dimming happens separately
for the RGB components, or is based on the intensity:
Example
RGB - this mode causes dimming to be
performed separately on the RGB components. For example, a pure white
diffuse color and pure red reflection color will give a surface with
cyan diffuse color (because the red component is already taken by the
reflection).
Monochrome - this mode causes dimming to
be performed based on the intensity of the diffuse/reflection/refraction
levels.
These determine the various texture maps used by the material.
These determine the options for the interpolation of glossy reflections.
They are very similar to the options for the irradiance map. Note that it is
not recommended to use interpolation for animations, since this may cause
severe flickering.
These determine the options for the interpolation of glossy reflections.
They are very similar to the options for the irradiance map. Note that it is
not recommended to use interpolation for animations, since this may cause
severe flickering.
