The Basics

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The Basics
To begin creating beautiful materials, we must first understand how the VRay material works. Let's take a closer look at the VRayMtl, VRayFastSSS2, and
VRayBlendMtl. These 3 are the main material types that are essential for realistic results, you can achieve almost anything with them. VRay offers even
more material types, but those are meant for pretty specific tasks and will not be covered in this guide.
Forget about using MAX Standard materials, they will give you slow, noisy and non-realistic results. VRay is designed to be used with it's native shaders,
so that is what we are going to do.
Let's get started.
VRayMtl is the basic, most used, universal material that VRay offers. You will find that most of the materials you wish to create can be made from a
VRayMtl.
This how the basic, unchanged material looks.
Now let's look at the first section – Diffuse
Think of Diffuse as the base color of the object. If you see a tomato, you can instantly tell it's red. This means that red is the Diffuse color. It is a bit more
complicated for very reflective or very refractive objects, but we will look at those later.
VRayMtl allows you to choose a simple color as the Diffuse or use a Map. You can use any Bitmap or Procedural Map in the Map slot.
Here is an example.
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The Roughness parameter can “flatten” the color transitions. You can use it to make your material appear dusty and flat. Here is an example with the
same green material at 0, 0.5 and 1.0 Roughness.
Next section is Reflection
As the name suggests, this section deals with the reflective properties of the material. Most real world objects are reflective. Look at these photos of chrome
and brick for example.
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The reflections of the chrome are very strong and sharp, you can instantly recognize it as a reflective surface. But what about the brick? It might look that it's
not reflective at all, but in fact the reflections are just weak and very very blurred. The only objects that don't reflect any light are the black holes :) Keep this
in mind when creating the materials.
Let's look at the parameters now.
First is the Reflection color.
Black color makes the material non-reflective, white color makes it fully reflective. All the gray scale values between increase or decrease the reflection
strength. The color sliders in 3Ds Max go from 0 to 255, this means that if you want to make a material that reflects 50% of the light that hits it, you need to
set the value of the reflections to 128. Here is an example at 0, 128 and 255. Notice how the third image has lost all the Diffuse color and is only showing the
reflections. Reflections make the base color weaker as they get stronger. The Energy Preservation law doesn't allow realistic materials to reflect more light
than they receive. This means that If the material has 0% reflections, it shows 100% of the Diffuse color. If the material has 30% reflections, the Diffuse color
is weakened to just 70%, and so on. Think of the reflections as a layer on top of the Diffuse, together they create the final image.
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Just like with the Diffuse, you can use Color, Bitmap or Procedural map in the Reflect slot. Here is an example with all three.
The Diffuse color for all the examples is 128 gray. Notice how the Reflect color changes the look of the Diffuse. This color change happens because VRay
adheres to the Energy Preservation rule. If the material reflects the red colored light, the red color is subtracted from the Diffuse and only green and blue are
left. This behavior can sometimes make it difficult to predict the final result, this is why you can change the Energy Preservation mode in the material
options. If you choose Monochrome, only the reflections will be colored and the Diffuse color will be left unchanged.
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Next up is Reflection Glossiness. This is the parameter that controls how sharp/blurred are the reflections. Some real world objects, like polished metal,
mirror, chrome, have very sharp reflections, while other materials, such as wood, concrete, plastic, etc., have blurred reflections. You can adjust the
Reflection glossiness from 0 to 1 (completely blurred to perfectly sharp). For most materials you will not need to lower the glossiness below 0.3. You should
always use blurred reflections with caution, do not lower the glossiness more than necessary, as this will cause more noise in your image, you can get rid of
it by increasing the Subdivs, but it will take a toll on the rendertime. Here are some basic examples of how the glossiness works.
Notice the noise introduced into the image. You can clean it up with the Subdivs parameter, increasing it will make reflections smoother at the cost of render
time. Notice how the render time has increased 3.5 times if you compare the third and first images. 16 is a good choice for decent result without too much
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waiting. You can use the subdivs parameter to find a balance between time and quality.
I do not recommend unlocking Highlight glossiness and changing it, if your goal is realistic materials. This parameter allows you to 'fake' the blurred
reflections without actually calculating them. It can sometimes be used for quicker renders if deadlines are tight.
Next up is the Fresnel parameter. You might have heard that all real world materials feature Fresnel reflections, but what does it actually mean? Fresnel
changes the reflection strength depending on the viewing angle. General rule is that reflections are weaker if the surface is facing you perpendicularly and
increase in strength as the surface approaches parallel position relative to your viewing angle. Here are some real world examples where you can see this
effect in action. The marble, car and wall surfaces are much more reflective when they are more parallel to the viewing angle.
And here is how the Fresnel IOR or Index of Refraction works. Use only values from 1.01 up, lower values are not physically correct for normal materials.
Increasing the IOR changes the relationship between the angle of the surface and reflection strength, look at the examples.
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As a general guideline, here are the Reflect IOR values for some common object types:
water 1.33
plastic 1.45
glass 1.5-1.8
diamond 2.4
compound materials like wood, stone, concrete etc 3-6
metals 20-100
Exact values need to be fine tuned for each material to achieve the right look.
Next parameter is Reflection Depth. This is the number of times a light ray is reflected before stopping the calculations. When the set number of reflections
has been calculated, the rest are simply displayed as the Exit color. You can try setting a bright color as the Exit color to see how much information you lose.
Look at the example, the green parts show the areas which would benefit from a larger number of reflections. As you can see, 6 reflections are plenty for this
scene. Other scenes with more reflective surfaces might need a larger value.
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Let's move on to the next section – Refractions
These settings control if and how the material let's the light through it. Common materials that have refractive properties are glass, water, gems, transparent
plastics, etc.
First parameter that controls the refractions is Refract color. As before, it goes from black (no refractions) to white (full refractions) and everything in between
is a mix between Diffuse and Refraction.
Here are some examples with a black material. I recommend using black diffuse color [1;1;1] for most of the transparent materials and adjust the overall
color with Refract color and Fog color.
You can use a color, bitmap or procedural map in this slot as well.
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Refraction glossiness. Just like with the reflections, you can change how blurry are the refractions. This effect is great for frosted glass or any other rough
surface that lets through the light but distorts it along the way.
This one increases render times and noise a lot so be careful with it. No need to go lower than 0.6 for most materials.
To clean up the noise, we need to increase Subdivs parameter. As you can see, getting a clean result comes with a huge cost. The render time for the last
image is almost 7 times longer than with the default value. It is also 15 times longer than not using blurred refractions at all! So try to minimize the blurred
refractions if you need fast renders.
In the real world light changes it's angle as it travels between objects of different density, thus the surface 'refracts' the light. IOR value of 1 let's the light
through without bending it, as the IOR value increases, so does the angle at which light is refracted. Look at these examples.
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Index of Refraction has been calculated for many materials, so you don't need to guess. You can find various IOR tables on the internet. Here is one of
them:
Acetone 1.36
Actinolite 1.618
Agalmatoite 1.550
Agate 1.544
Agate, Moss 1.540
Air 1.0002926
Alcohol 1.329
Alexandrite 1.745
Aluminum 1.44
Amber 1.546
Amblygonite 1.611
Amethyst 1.544
Anatase 2.490
Andalusite 1.641
Anhydrite 1.571
Apatite 1.632
Apophyllite 1.536
Aquamarine 1.577
Aragonite 1.530
Argon 1.000281
Asphalt 1.635
Augelite 1.574
Axinite 1.675
Azurite 1.730
Barite 1.636
Barytocalcite 1.684
Benitoite 1.757
Benzene 1.501
Beryl 1.577
Beryllonite 1.553
Brazilianite 1.603
Bromine (liq) 1.661
Bronze 1.18
Brownite 1.567
Calcite 1.486
Calspar 1.486
Cancrinite 1.491
Carbon Dioxide (gas) 1.000449
Carbon Disulfide 1.628
Carbon Tetrachloride 1.460
Cassiterite 1.997
Celestite 1.622
Cerussite 1.804
Ceylanite 1.770
Chalcedony 1.530
Chalk 1.510
Chalybite 1.630
Chlorine (gas) 1.000768
Chlorine (liq) 1.385
Chrome Green 2.4
Chrome Red 2.42
Chrome Yellow 2.31
Chromium 2.97
Chrysoberyl 1.745
Chrysocolla 1.500
Chrysoprase 1.534
Citrine 1.550
Clinozoisite 1.724
Cobalt Blue 1.74
Cobalt Green 1.97
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Cobalt Violet 1.71
Colemanite 1.586
Copper 1.10
Copper Oxide 2.705
Coral 1.486
Cordierite 1.540
Corundum 1.766
Crocoite 2.310
Crystal 2.00
Cuprite 2.850
Danburite 1.633
Diamond 2.417
Diopside 1.680
Dolomite 1.503
Dumortierite 1.686
Ebonite 1.66
Ekanite 1.600
Elaeolite 1.532
Emerald 1.576
Emerald, Synth flux 1.561
Emerald, Synth hydro 1.568
Enstatite 1.663
Epidote 1.733
Ethanol 1.36
Ethyl Alcohol 1.36
Euclase 1.652
Fabulite 2.409
Feldspar, Adventurine 1.532
Feldspar, Albite 1.525
Feldspar, Amazonite 1.525
Feldspar, Labradorite 1.565
Feldspar, Microcline 1.525
Feldspar, Oligoclase 1.539
Feldspar, Orthoclase 1.525
Fluoride 1.56
Fluorite 1.434
Formica 1.47
Garnet, Almandine 1.760
Garnet, Almandite 1.790
Garnet, Andradite 1.820
Garnet, Demantoid 1.880
Garnet, Grossular 1.738
Garnet, Hessonite 1.745
Garnet, Rhodolite 1.760
Garnet, Spessartite 1.810
Gaylussite 1.517
Glass 1.51714
Glass, Albite 1.4890
Glass, Crown 1.520
Glass, Crown, Zinc 1.517
Glass, Flint, Dense 1.66
Glass, Flint, Heaviest 1.89
Glass, Flint, Heavy 1.65548
Glass, Flint, Lanthanum 1.80
Glass, Flint, Light 1.58038
Glass, Flint, Medium 1.62725
Glycerine 1.473
Gold 0.47
Hambergite 1.559
Hauynite 1.502
Helium 1.000036
Hematite 2.940
Hemimorphite 1.614
Hiddenite 1.655
Howlite 1.586
Hydrogen (gas) 1.000140
Hydrogen (liq) 1.0974
Hypersthene 1.670
Ice 1.309
Idocrase 1.713
Iodine Crystal 3.34
Iolite 1.548
Iron 1.51
Ivory 1.540
Jade, Nephrite 1.610
Jadeite 1.665
Jasper 1.540
Jet 1.660
Kornerupine 1.665
Kunzite 1.655
Kyanite 1.715
Lapis Gem 1.500
Lapis Lazuli 1.61
Lazulite 1.615
Lead 2.01
Leucite 1.509
Magnesite 1.515
Malachite 1.655
Meerschaum 1.530
Mercury (liq) 1.62
Methanol 1.329
Moldavite 1.500
Moonstone, Adularia 1.525
Moonstone, Albite 1.535
Natrolite 1.480
Nephrite 1.600
Nitrogen (gas) 1.000297
Nitrogen (liq) 1.2053
Nylon 1.53
Obsidian 1.489
Olivine 1.670
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Onyx 1.486
Opal 1.450
Oxygen (gas) 1.000276
Oxygen (liq) 1.221
Painite 1.787
Pearl 1.530
Periclase 1.740
Peridot 1.654
Peristerite 1.525
Petalite 1.502
Phenakite 1.650
Phosgenite 2.117
Plastic 1.460
Plexiglas 1.50
Polystyrene 1.55
Prase 1.540
Prasiolite 1.540
Prehnite 1.610
Proustite 2.790
Purpurite 1.840
Pyrite 1.810
Pyrope 1.740
Quartz 1.544
Quartz, Fused 1.45843
Rhodizite 1.690
Rhodochrisite 1.600
Rhodonite 1.735
Rock Salt 1.544
Rubber, Natural 1.5191
Ruby 1.760
Rutile 2.62
Sanidine 1.522
Sapphire 1.760
Scapolite 1.540
Scapolite, Yellow 1.555
Scheelite 1.920
Selenium, Amorphous 2.92
Serpentine 1.560
Shell 1.530
Silicon 4.24
Sillimanite 1.658
Silver 0.18
Sinhalite 1.699
Smaragdite 1.608
Smithsonite 1.621
Sodalite 1.483
Sodium Chloride 1.544
Sphalerite 2.368
Sphene 1.885
Spinel 1.712
Spodumene 1.650
Staurolite 1.739
Steatite 1.539
Steel 2.50
Stichtite 1.520
Strontium Titanate 2.410
Styrofoam 1.595
Sulphur 1.960
Synthetic Spinel 1.730
Taaffeite 1.720
Tantalite 2.240
Tanzanite 1.691
Teflon 1.35
Thomsonite 1.530
Tiger eye 1.544
Topaz 1.620
Topaz, Blue 1.610
Topaz, Pink 1.620
Topaz, White 1.630
Topaz, Yellow 1.620
Tourmaline 1.624
Tremolite 1.600
Tugtupite 1.496
Turpentine 1.472
Turquoise 1.610
Ulexite 1.490
Uvarovite 1.870
Variscite 1.550
Vivianite 1.580
Wardite 1.590
Water (gas) 1.000261
Water 100'C 1.31819
Water 20'C 1.33335
Water 35'C (Room temp) 1.33157
Willemite 1.690
Witherite 1.532
Wulfenite 2.300
Zincite 2.010
Zircon, High 1.960
Zircon, Low 1.800
Zirconia, Cubic 2.170
Max depth works just like with the reflections. The default value is usually fine, but for scenes with large amount of refractions, you should increase it.
Next parameter is Fog Color. It is great if you want to tint the glass in a realistic way. Using the Fog color makes thinner parts lighter and thicker parts
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darker. You can use the Fog multiplier value to adjust how strong is the tint. I suggest using colors with less than 255 lightness and saturation for realistic
results.
You can control the relationship between object thickness and Fog intensity by using the Fog Bias value. Look at the examples to see how it works.
Negative values make the tinting stronger and color transitions more extreme, while positive values make the fog smoother and weaker. Use it together with
fog multiplier to get the effect you need.
The biggest drawback of the Fog color is that you can not use a map in this slot, this means you can only use a single color. If you want to create a stained
glass material or glass with multiple colors, you will have to do that by using the Refract color and not the Fog. It is, however, great for those single-colored
materials and much more realistic than simply changing the Refract color.
VRay 2.0 introduced the long awaited Dispersion feature for refractive materials, until 2.0 you had to use a 'fake' method of blending multiple materials with
different Refract colors and IOR. Now you can simple activate the Dispersion and change the strength with Abbe number. Smaller values makes the
dispersions stronger, while larger numbers makes them more subtle. Use your own artistic eye to figure out how much dispersions you need. You will have
to increase the Refract Subdivs for a nice result (with the default value materials have a green tint), even if you are not using glossy refractions. Dispersion
also increases the render time.
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Next section is Translucency, but we are going to skip it, as I prefer to use VRayFastSSS2 material for translucent objects. It offers much greater speed and
flexibility.
Let's look at the BRDF section.
First is the BRDF model. This parameter affects how the specular highlights of the material are calculated. VRay offers 3 options: Phong, Blinn and Ward.
Phong has the sharpest highlights, Blinn is a bit more blurred and Ward is even softer. Blinn is the default value and it is fine for most materials, for metals
you will want to use the Ward model.
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Anisotropy allows you to create stretched highlights. In real world these are most commonly seen on brushed metal surfaces with long, parallel 'scratches'.
Anisotropy allows you to fake this by stretching and rotating the highlights as you like.
This example shows how changing the Anisotropy value changes the speculars. Negative values stretch them highlights horizontally while positive values
stretch them vertically.
You can also change the angle manually to any value you need. Here is an example with stretching rotated at 45 degrees.
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And finally you can change the reference axis for even more control.
Next comes the Maps section of the material. This is a convenient list of all the slots you can assign bitmaps or procedural maps to.
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There are some important properties of the material that can only be accessed through this section. These are Bump, Displace and Opacity.
Let's look at the Bump and Displace slots first.
Both of these slots allow you to assign a bitmap or procedural map to simulate unevenness and deformation of the objects surface. Bump does so without
changing the overall geometry of the object, but Displace actually subdivides and deforms the object during rendering. The deformations work like this –
middle grey [128;128;128] of the map does not change anything on the object, darker values push the surface inwards while lighter values pull it out. The
further this value is from medium gray, the stronger is the effect. Color of the map is not taken into account and only the lightness value is used.
Bump is fast and Displace is slow.
If you need large, realistic deformations, you should use displacement, while bump is perfect for smaller things that don't change the objects outline. Look at
the examples to see the difference.
Last map we are going to look at is the Opacity map. It works very simple. Pure white value is used for the non-transparent parts of the material and pure
black is for completely invisible parts of the material, everything in between is more or less half transparent. It is great if you need to simulate stuff like tree
leaves or lace fabric without using a large amount of polygons. Here is an example using the same map as in the Bump samples.
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The two next segments of VRayMtl are Reflect Interpolation and Refract Interpolation. They are supposed to be a quicker way for calculating blurred
reflections and refractions, but I will not be covering those, as I have often found troubleshooting the issues/glitches that can appear from them take longer
time than rendering non-interpolated materials.
This wraps up the basic VRayMtl, it already allows you to create 90% of the materials you will encounter in your work. There are, however, some special
cases where other materials are better suited.
Let's look at the VRayBlendMtl. It is the perfect tool for making compound materials.For example, if you need to create a black, shiny surface with blurred
gold spots, it is way easier to create two materials and blend them together than hand painting all the different maps you would need to achieve this effect in
a single VRayMtl.
The VRayBlendMtl works with a layer-like system.
There is a Base material to which you can apply multiple Coat materials. You can control how much of the coat material is applied by using Blend Amount
color, Bitmap or Procedural map. Pure white blend color shows only the coat material, medium gray shows 50% of the coat material and 50% of the base
material and finally pure black doesn't show any coat material at all.
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Here is the same blend material with black and white checker map in the Blend Amount slot.
Each next coat layer treats everything above it as a single material, if you have a base material and 2 coat materials at 50%, the result is
0.5(0.5base+0.5_1st_coat)+0.5_2nd_coat.
In this example I've added a second coat layer with pure green diffuse color, if all 3 parts would be used equally, the resulting color should be white (RGB at
equal values result in grayscale color), but it is instead a 50/50 mix of purple and green.
You can use up to 10 material in a blend (if you then create a new VRayBlendMtl and keep the filled one as sub-material, you can add 9 more materials,
repeating this procedure gives you unlimited amount of slots). Here is a somewhat more complex example of a 4 material blend.
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I am sure you now see the potential of VRayBlendMtl. I will show you some practical examples on how to use it a bit later.
Let's move on to the next material type – VRayFastSSS2. The letters SSS stand for Sub-Surface Scattering, another common name is Translucency. This
effect happens when light rays don't go straight through the object, but are scattered in multiple directions when inside, this does not allow you to see
through the object, but you can see the light inside it. Unlike refraction glossiness which scatters light rays at the surface, SSS does this inside the object.
This makes some interesting lighting effects, the light penetrates the object and lights it from within. Some real world examples are: flesh, milk, marble, jade,
fruit, wax etc. Look at these photos to see what I'm talking about.
VRayfastSSS2 is perfect for this type of materials.
My example scene for this section has just one light behind he object to illustrate the sss effects better.
Compare the VRaymtl and VRayfastSSS2. Notice how the regular material doesn't let any light in, only bounces it off the surface while VRayfastSSS2 is
more illuminated. The effect is very subtle though.
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The easiest way to increase the translucency effect, is by increasing the Scale setting. The larger the Scale, the deeper light goes into the object.
Next parameter, SSS prepass, controls the accuracy of the scattered light. Lower values give blurrier results, while higher values give a more precise
rendering, the precision comes with an increased render time. For production renders, I suggest using values of -1 to 1.
Fast SSS allows you to set the IOR as well. Most water based materials like skin, milk, juice, plants have IOR of ~1.3, for stone type materials 1.5-1.7 is
more suitable.
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You can also use the built-in presets to quickly create some common materials, these are:
Skin (brown)
Skin (pink)
Skin (yellow)
Milk (skimmed)
Milk (whole)
Marble (white)
Ketchup
Cream
Potato
Spectralon
Water (clear)
If none of the presets fits, you can create the material yourself.
Let's look at the settings.
First is the Overall color. This color allows you to change the color of the whole material (the surface and the inside).
Look at the examples to see how this colors changes the look of the default VRayfastSSS2 material.
Next is the Diffuse color and Sub-Surface color. First one controls the outer surface, second one controls the inside of the object. This works somewhat
different than VRaymtl. By default, VRayfastSSS2 only uses the sub-surface color and scatter color as the main sources of pigment. You can assign a
diffuse color and increase the diffuse amount to mix it with those two colors. It is a bit hard to explain, I'll show you an example. Here I have assigned a Red
Diffuse color and a Blue sub-surface color. With the default setting of 0 Diffuse is not seen at all, when I increase it to 0.5 it is a 50% mix with the blue and
finally, when I set it at 1, there is no more translucency and only the red diffuse color is seen.
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Ok, let's look at the Scatter color now. The lightness of this color affects how strong is the scattering effect. It get's stronger from black to white, as usual.
I'm using a simple grey material with red sub-surface color in this example.
You can also use a saturated color in this slot to give a tint to the object. It work's best if you use a color that is close to the sub-surface color. It also tints in
the opposite direction, sounds weird, I know. What it means is if your sub-surface color is red and you set the scatter color as orange, the actual tint will be to
the opposite direction of the hue scale – purple. If you use purple, the tint will be orange. Look at the pictures to see it in action. The effect is subtle, but
sometimes it's just what is needed!
Scatter Radius works just like Scale, you can increase the depth of translucency by increasing this value.
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Let's look at the Specular Layer now.
You can make the VRayfastSSS2 material reflective by enabling Trace Reflections option. You can control the look of the highlights just like with the VRaymtl
– by changing the glossiness value.
All these settings – glossiness, subdivs, reflection depth work just like in the basic VRaymtl.
Let's move on to the Options section.
The main setting here you need to focus your attention is Single Scatter mode.
There are 3 possibilities you should use depending on the material you are trying to create.
Simple mode is best for materials where the light doesn't go too deep, best examples are skin, plastic.
Refractive mode is great for materials that are very translucent but at the same time quite opaque (marble, milk)
Refractive (raytraced) mode is for more transparent materials, this also creates nice refractions and transparent shadows. Use it for materials like glass,
water, crystals.
For the best results, turn Front lighting, Back lighting and Scatter GI on.
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5/6/2012 10:38 µµ
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