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Vray Tutorials |
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Vray Basic render settings |
Before you start
This tutorial will explain very briefly many of the Vray render settings. A very basic 3D Studio Max knowledge is needed to be able to follow the tutorial. For more info on each topic, please refer to the online manual.
It's also a good thing if you have a basic understanding of rendering in general. Terms like Global Illumination, raytracing, antialiasing, displacement and so on should sound familiar before you start working with Vray.
The Vray version I used for this tutorial is 1.47.03.
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1. Set Vray as the production renderer
Open the render settings dialog, go to the current
renderer rollout and click the assign button for production renderer. Choose
Vray from the list. |
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2. Extra rollouts!
After Vray has been set as the main renderer, you'll
notice a lot of new rollouts. Every rollout with "Vray:" in front of its name is
filled with Vray render settings... The next steps will each cover one rollout
in general. |
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3. Vray frame buffer
When enabled, the Vray frame buffer replaces the Max
virtual frame buffer. The Vray frame buffer has much more options to post
process images and lots of other interesting settings.
In this rollout you
can control the size of it by disabling the 'get resolution from max' checkbox.
Rendering to Vray raw image file enables you to render very high resolution
images, without eating up all the available RAM.
The use of the Vray
frame buffer is for advanced Vray users only. Don't bother using it when you're
new to Vray. |
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4. Vray global switches
Here you can control and override many of Vray's
settings, mainly used to speed up test rendering.
You can turn off all
displacement, lights, default max lights, hidden lights and shadows by just
unticking the appropriate checkbox!
The "don't render final image"
button is used to let Vray only compute the GI (irradiance map for example)
without actually rendering the image. Forget this for now :-)
Turn all
reflections and refractions in the scene on or off by unticking the checkbox.
Very usefull for testing purposes. The max depth controls the depth of the
reflection/refraction (the number of times a ray can reflect/refract before it
is being ignored in the raytracing process).
You can also turn off al
maps, all filtering of maps etc... Glossy effects are for example blurry
reflections or refractions. Turning them off greatly improves rendertime, very
neat while doing testrenders.
Override material can be used to give every
object in the scene the same material.
Secondary ray bias: please refer
to the manual. |
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5. Image sampler (Antialiasing)
In Vray, you can choose between 3 types of image
samplers to compute the anti aliasing of the image. This controls how sharp and
smooth your image will be, and has a huge effect on rendertimes!
Fixed
rate is very predicatble, but slow in many cases. Use this one if there are a
lot of glossy materials, area shadows, motion blur etc... Higher subdivs means
better quality, higher rendertimes.
Adaptive QMC is my favourite. As its
name already indicates, it's an adaptive sampler, it will adapt its calculation
to the situation. It will compare the quality of the computed pixel by some
thresholds, and decide if it's good enough or if there's more calculation
needed.
This samplers quality is controlled by the QMC rollout (further down
in the rollouts). Use adaptive QMC if you have many glossies, area shadows,
motion blur etc in your scene, and if you want maximum control over the speed vs
quality of the image. It takes some time to get a grip on it, but once you get
it, you have full control over Vray with just a few clicks.
Adaptive
subdivision is also an adaptive method. Although very fast is many cases, it can
get very slow with lots of glossy effects in the scene. It also uses more RAM
memory while rendering. Use this sampler if you have large smooth areas in your
scene (for example an interior with large white walls). The min/max rates
control the quality, 0/2 are good values, -2/-1 are good for very fast test
renders.
Some testing will be needed to understand the differences
between the 3 samplers. The online documents have very good explanations on this
topic, with lots of examples showing all differences.
The anti aliasing
filter can be changed if you have problems with fine textures or fine details in
the scene. Every sampler has its own characteristics, but it is not the goal of
this tutorial to explain them all. In many cases you can get away by simply
turning the filter off!
A few filters I use often:
- none
- mitchell
netravali: smooth result, good controls
- catmull rom: very sharp (a bit like
the result of 'unsharp mask' in photoshop)
- soften with radius around 2.5
(smooth and fast) |
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6. Indirect illumination (GI)
This rollout controls the main options for the GI (=
bounced light). Like most GI renderers, Vray makes a difference between first
and secondary bounces.
A simple spotlight will cast direct light. This
light hits an object and will be absorbed a bit, but the rest bounces back into
the scene. This is the first bounce. This first bounce will probably hit another
object and will bounce again (second bounce) and so on untill no energy is
left.
The direct light and first bounce will have the largest impact on
the lighting look, because this bounced light has still a lot of energy. So
these need to be computed very accurately to create realistic lighting. The
secondary bounces are usually less important (a lot of the light energy is
already absorbed, there's less impact on the visual result), so approximisations
can be rougher here. (interior scenes are an exception, the secondary bounces
become important too)
You can choose between different ways of computing
first and second bounces, and adjust the strength of them (multipliers). With
the post processing options you can desaturate the GI, or change its contrast.
Caustics are light patterns formed by refracted/reflected light. GI
caustics are caustics created by refracted/reflected GI light (light bounces).
The standard first and secondary bounces don't take the reflective/refractive
material properties into account, only the diffuse properties. You need to turn
them on or off with the two appropriate checkboxes.
An example of very
visible reflective caustics is the light pattern you will see if you put a
spotlight on a chrome ring lying on a table. Refractive caustics are generated
for example by a glass sphere, which bundles all light that passes through it,
creating a very bright spot underneath it.
Note that when you want GI light
to pass trough transparent objects, you must set 'refractive GI' caustics ON!
Remember that caustics is only a name for refracted/reflected light. So even
without these typical lighting patterns, light that is reflected or refracted is
being called 'caustics'. For example light going trough a flat window are also
caustics.
A special case is light coming from a max spotlight for
example (or any other max light). This is direct light and not GI light, so Vray
gives you the ability to render these 'direct light caustics' too. These options
have their own rollout (see step 8). You will notice that light from a spotlight
doesn't penetrate transparent objects in Vray. This is because by default,
direct light caustics are not enabled. So if you want light to pass trough
transparant materials, you either have to enable caustics (which will take
longer to render), or use a fake caustics option in the transparant vray
material (='affect shadows' option in the refration properties of the material). |
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7. Irradiance map / Quasi monte carlo / photon mapping
/ light cache
Depending on the method for
first and secondary bounces you have chosen, the above rollouts will appear.
They are all ways of calculating GI bounces. Each have their specific advantages
and uses. I will explain these in a seperate tutorial as this is too complicated
for this basic settings overview.
For now, remember that all these
methods are ways to approximate GI lighting. GI calculations are very time
consuming, that's why methods are invented to speed things up by using
approximate values. |
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8. Caustics
Remember the direct light caustics from step 6? Well,
here you can turn them on or off, and control some parameters. To get nice
direct light caustics, you will also need to make adjustments in the Vraylight
settings. If I find the time, I will make a direct caustics tutorial too!
A simple trick to eliminate the need for direct light caustics, is
simply not to use direct lights :-) With only GI light, you tick
'refractive/reflective GI caustics' in the Indirect Illumination rollout and all
caustics will be calculated according to your GI settings! Of course it is not
always possible to use only GI light... But if you only use skylight and vray
light types, you can eliminate the need for direct caustics. |
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9. Environment
Vray allows you to override the Max environment with
these controls.
Use the skylight to light the scene with a 'skylight'.
If you put a map in the slot behind it, the color swatch is neglected and
instead, the map is used to light the scene. You need to enable GI for the
skylight to become visible. The skylight is not a direct light, it's actually
treated as first bounce, that's why GI is needed to make the skylight visible.
Note that if GI is enabled, skylight is turned off and you have put a color in
the Max background, that color will be used as skylight!
The other swatch
controls the reflection/refraction environment. No matter what the max
environment is, your objects will always reflect/refract this Vray override. You
can also put a map in there like with the skylight option.
Note that
these settings will not show up in the background of the render! Use the Max
environment setting for this. |
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10. QMC Sampler
The QMC sampler can be seen as a global quality control
center. It controls all paramters that have anything to do with Quasi Monte
Carlo calculations like adaptive QMC AA, QMC GI, Irradiance map, Glossy effects,
area shadows, Motion Blur and Depth of field.
The most important
parameter is the noise threshold, this controls the accuracy of al the
calculations. The highest quality setting is 0.001, but this of course requires
the longest rendertime. The global subdivs multiplier can be used to
lower/increase all subdivision parameters in the scene (Irradiance map, QMC GI,
glossies, area shadows, Motion Blur, Depth of field,...). This is very usefull
for fast testrenders. |
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11. Color mapping
Color mapping can be used to kinda post process an image
within Vray. Please refer to the manual for more information about the different
types. |
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12. Camera
You
can choose different camera types instead of the default standard Max camera,
for example fish eye lense, spherical camera, cylindrical etc... Please refer to
the manual for more information about these different camera types.
Depth
of field is an effect caused by the diameter of the diafragma opening of the
camera. Objects that are out of focus will become blurred. The further away from
focus and the bigger the diafragma, the more the object will be blurred.
Motion blur is the blur that you get when objects move very fast, or
when the camera is moving. In real life this is due to shutter time of the
camera.
Both of these effects are raytraced, not faked with some fancy
tricks, so they have a big impact on rendertimes... |
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13. Default displacement
These parameters control the default Vraydisplacement
settings. More on displacement can be found in the online manual, with lots of
illustrations. |
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14. System
Another rollout that controls all kinds of general
parameters.
Raycaster parameters are used to control the amount of
memory Vray uses for a specific scene. In 99% of all cases you don't need to
touch these!
Render region division. X and Y control the width and height
of a render bucket. For small render resolutions, you can lower these, for high
resolutions you can increase these. Good values are squares between 32 and
128px. Region sequence alters the order in which the buckets get rendered.
Distributed rendering is the process of rendering 1 image with different
PC's.
"Previous render" controls how the previous render in the frame
buffer is overwritten by the new buckets.
Default geometry
static/dynamic: refer to the manual.
Frame stamp is usefull to print
rendertimes and such on the rendered image.
Objects and lights settings
control Vray specific properties for scene objects and lights. You can turn
off/on all kinds of things locally for each object in the scene.
Presets
can save all or some render settings for easy and quick switching between for
example test settings or high quality settings.
The Vray log is the small
window that appears while rendering, giving you some textual feedback about the
rendering process. The level controls how much feedback is printed inside the
box. |
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