Wouter_Tutorials1_SpellCheck

Basics of the V-Ray Render Settings

This tutorial will explain very brieﬂy many of the V-Ray
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, raytrac-
ing, antialiasing, displacement and so on should sound familiar

before you start working with V-Ray.

The V-Ray version I used for this tutorial is 1.47.03.

INTRODUCTION

Basics of the V-Ray Render Settings

1. Set V-Ray as the production renderer

Open the render settings di-
alog. Then, go to the current

renderer rollout and click
the assign button for pro-
duction renderer. Choose

V-Ray from the list.

2. Extra rollouts!

After V-Ray has been set as the main ren-

derer, you’ll notice a lot of new rollouts.
Every rollout with “V-Ray” in front of its

name is ﬁlled with V-Ray render settings...
The next steps will each cover one rollout

in general.

Basics of the V-Ray Render Settings

3. V-Ray frame buffer

When enabled, the V-Ray frame buffer replaces the
Max virtual frame buffer. The V-Ray frame buffer has

many 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’ check box.
Rendering to V-Ray raw image ﬁle enables you to

render very high resolution images, without eating
up all the available RAM.

The use of the V-Ray frame buffer is for advanced
V-Ray users only. Don’t bother using it when you’re

new to V-Ray.

4. V-Ray global switches

Here you can control and

override many of V-ray’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 unchecking

the appropriate check box!

The “don’t render ﬁnal
image” button is used to let

V-Ray 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 unchecking the
check box. Very useful 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 all

maps, all ﬁltering of maps
etc... Glossy effects are for

example blurry reﬂections or

refractions. Turning them off
greatly improves render time,

very neat while doing test
renders.

Override material can be used
to give every object in the

scene the same material.

Secondary ray bias: please

refer to the manual.

Basics of the V-Ray Render Settings

In V-Ray, 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 render times!

Fixed rate is very predictable, 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 render times.

Adaptive QMC is my favorite. As it’s

name already indicates, it is 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

are 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 maxi-

mum 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 V-Ray with just a few

clicks.

Some testing will be needed to under-
stand the differences between the 3 sam-

plers. 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 with
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)

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

5. Image sampler (Antialiasing)

Basics of the V-Ray Render Settings

This rollout controls the main options for the GI
(bounced light). Like most GI renderers, V-Ray 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 until 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 second-
ary bounces are usually less important (a lot of the

light energy is already absorbed, there’s less impact on
the visual result), so approximations 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). Post processing options can desatu-

rate the GI light, or its contrast.

Caustics are light patterns formed by refracted/reﬂect-

ed light. GI caustics are caustics created by refracted/
reﬂected GI light (light bounces). The standard ﬁrst

and secondary bounces don’t take the reﬂective/refrac-

tive material properties into account, only the diffuse
properties. You need to turn them on

or off with the two appropriate check
boxes.

An example of very visible reﬂective caus-
tics 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. Because light

coming from a max spotlight, for example,
is direct light and not GI light, you also

have the ability in V-ray to render these
direct light caustics.

6. Indirect illumination (GI)

Basics of the V-Ray Render Settings

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 separate tutorial as this is too com-
plicated for this basic settings overview.

For now, remember that all these methods are ways to approxi-
mate GI lighting. GI calculations are very time consuming, that’s

why methods are invented to speed things up by using approxi-
mate values.

7. Irradiance map / Quasi-Monte Carlo
/ photon mapping / light cache

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 V-Ray light settings. If I ﬁnd the time, I will make a direct

caustics tutorial too!

8. Caustics

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 set-
tings! Of course it is not always possible

to use only GI light...

Basics of the V-Ray Render Settings

V-Ray 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!

9. Environment

The other swatch controls the reﬂection/
refraction environment. No matter what

the max environment is, your objects will
always reﬂect/refract this V-Ray 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.

The QMC sampler can be seen as a global quality control center.

It controls all parameters that have anything to do with Quasi
Monte Carlo calculations like adaptive QMC AA, QMC GI, Irradi-

ance map, Glossy effects, area shadows, Motion Blur and Depth of

ﬁeld.

The most important parameter is the noise threshold, this con-
trols the accuracy of al the calculations. The highest quality set-

ting is 0.001, but this of course requires the longest render time.
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
useful for fast test renders.

10. QMC Sampler

Basics of the V-Ray Render Settings

Color mapping can be used to post pro-
cess an image within V-Ray. Please refer to
the manual for more information about the

different types.

11. Color mapping

Depth of ﬁeld is an effect caused by the

diameter of the diaphragm opening of the

camera. Objects that are out of focus will
become blurred. The further away from

focus and the bigger the diaphragm, the

more the object will be blurred.

Motion blur is the blur that you get when
objects move very fast, or when the cam-

era is moving.

Both of these effects are raytraced, not

faked with some fancy tricks, so they have
a big impact on render times...

12. Camera

You can choose different camera types instead of the default

standard Max camera, for example ﬁsh eye lens, spherical camera,
cylindrical etc... Please refer to the manual for more information

about these different camera types.

These parameters control the default V-Ray

displacement settings. More on displace-

ment can be found in the online manual,
with lots of illustrations.

13. Default displacement

Basics of the V-Ray Render Settings

Another rollout that controls all kinds of general parameters.

Raycaster parameters are used to control the amount of memory
V-Ray 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 one image with different PC’s.

“Previous render” controls how the previ-

ous render in the frame buffer is overwrit-
ten by the new buckets.

Default geometry static/dynamic: refer to

the manual.

Frame stamp is useful to print render times and such on the ren-
dered image.

Objects and lights settings control V-Ray speciﬁc properties for

scene objects and lights. You can turn on/off 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 set-

tings.

The V-Ray 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.

14. System