In this section you can control variety of VRay parameters. These are
divided into the following sections:
Raycaster parameters
Here
you can control various parameters of VRay's Binary Space Partitioning (BSP)
tree.
One of the basic operations that VRay must perform is
raycasting - determining if a given ray intersects any geometry in
the scene, and if so - identifying that geometry. The simplest way to
implement this would be to test the ray against every single render
primitive (triangle) in the scene. Obviously, in scenes with thousands or
millions of triangles this is going to be very slow. To speed this process,
VRay organizes the scene geometry into a special data structure, called a
binary space partitioning (BSP) tree.
The BSP tree is a hierarchical data structure, built by subdividing the
scene in two parts, then looking at each of those two parts and subdividing
them in turn, if necessary and so on. Those "parts" are called
nodes of the tree. At the top of the hierarchy is
the root node - which represents the bounding box
of the whole scene; at the bottom of the hierarchy are the
leaf nodes - they contain references to actual
triangles from the scene.
Max tree depth - the maximum depth of the
tree. Larger values will cause VRay to take more memory, but the rendering
will be faster - up to some critical point. Values beyond that critical
point (which is different for every scene) will start to slow things down.
Smaller values for this parameter will cause the BSP tree to take less
memory, but rendering will be slower.
Min leaf size - the minimum size of a leaf
node. Normally this is set to 0.0, which means that VRay will subdivide the
scene geometry regardless of the scene size. By setting this to a different
value, you can make VRay to quit subdividing, if the size of a node is
below a given value.
Face/level coef - controls the maximum
amount of triangles in a leaf node. If this value is lower, rendering will
be faster, but the BSP tree will take more memory - up to some critical
point (which is different for every scene). Values below that critical point
will make the rendering slower.
Default geometry - internally VRay
maintains four raycasting engines. All of them are built around the idea of
a BSP tree, but have different uses. The engines can be grouped into
raycasters for non-motion blurred and for motion blurred geometry, as well
as for static and dynamic geometry. This parameter determines the type of
geometry for standard 3dsmax objects. Note that some objects
(displacement-mapped objects, VRayProxy and
VRayFur
objects, for example) always generate dynamic geometry.
Static geometry is precompiled into an
acceleration structure at the beginning of the rendering and remains
there until the end of the frame. Note that static raycasters are not
limited in any way and will consume as much memory as necessary.
Dynamic geometry is loaded and unloaded on
the fly depending on which part of the scene is being rendered. The
total memory taken up by the dynamic raycasters can be controlled within
certain limits.
Dynamic memory limit - the total RAM limit
for the dynamic raycasters. Note that this limit is divided between the
number of rendering threads. If you specify 400 MB total limit, for example,
and you have a dual processor machine with multithreading enabled, then each
rendering thread will use 200 MB for its dynamic raycaster. If this limit is
too low, and geometry needs to be loaded and unloaded very often, this may
turn out to be slower than rendering in single-threaded mode.
Render region division
Here you can control various parameters of VRay's rendering regions
(buckets). The bucket is an essential part of the distributed rendering
system of VRay. A bucket is a rectangular part of the currently rendered
frame that is rendered independently from other buckets. Buckets can be sent
to idle LAN machines for processing and/or can be distributed between
several CPUs. Because a bucket can be processed only by a single processor
the division of the frame in too small a number of buckets can prevent the
optimal utilization of computational resources (some CPUs stay idle all the
time). However the division of the frame in too many buckets can slow down
the rendering because there is a some time overhead related with each bucket
(bucket setup, LAN transfer, etc).
X - determines the maximum region width in
pixels (Region W/H is selected) or the number of
regions in the horizontal direction (when Region
Count is selected)
Y - determines the maximum region height
in pixels (Region W/H is selected) or the number
of regions in the vertical direction (when Region
Count is selected)
Region sequence - determines the order in
which the regions are rendered. Note that the default Triangulation sequence
is best if you use a lof of dynamic geometry (displacement-mapped objects,
VRayProxy or
VRayFur
objects), since it walks through the image in a very consistent manner so
that geometry that was generated for previous buckets can be used for the
next buckets. The other sequences tend to jump from one end of the image to
another which is not good with dynamic geometry.
Reverse sequence - reverses the Region
sequence order
Note: When the Image Sampler is set to
Adaptive Sampler the size of the buckets will be rounded up to the
nearest number which is a power of 2.
Previous render
This parameter determines what should be done with the previous image in
the virtual frame buffer when rendering starts. The possible values are:
Unchanged - no changes will be made - the
virtual frame buffer remains the same;
Cross - every second pixel of the image
will be set to black;
Fields - every other line of the image
will be set to black;
Darken - the colors in the image will be
darkened.
Note that this parameter has no effect on the final result of the
rendering; it is implemented simply as a convenient way to distinguish
between parts from the current frame being rendered, and part left over from
the previous rendering.
Distributed rendering
Distributed rendering is the process of
computing a single image over several different machines. Note that this is
different from distributing the frame over several CPU's in a single
machine, which is called multithreading. VRay
supports multithreading, as well as distributed rendering.
Before you can use the distributed rendering option, you must determine
the machines that will take part in the computations. Both 3dsmax and VRay
need to be properly installed on those machines, although they don't need to
be authorized. You must make sure that the VRay spawner application is
running on those machines - either as a service, or as a stand-alone
application. Refer to the Installation section for more details on configuring and running the
VRay spawner.
For additional information on distributed rendering, please refer to the
dedicated
Distributed rendering section.
Distributed rendering - this checkbox
specifies whether VRay will use distributed rendering.
Settings... - this button opens the VRay
Networking settings dialog. See the
Distributed rendering section for more information.
ShadeContext compatibility
VRay carries all its computations in world space. However, some 3dsmax
plugins (notably atmospherics) take it as granted that the renderer works in
camera space, because this is what the default scanline renderer does. To
preserve compatibility with such plugins, VRay emulates work in camera
space by converting the various points and vectors passed to and from other
plugins.
In addition to slowing down VRay by forcing it to convert values all the
time, working in camera space messes up with camera modifiers such as the
Technical camera script. This why you have the option of turning off the
camera-space emulation.
Frame stamp
The frame stamp is a convenient way to put some short text over the
rendered images. It can be useful in many ways - for example, in network
rendering, to quickly determine which frames were rendered by which machine.
The frame stamp is one line of text, which appears at the bottom of the
image.
Checkbox - turns the frame stamp on and
off.
Edit box - here you enter the text you
wish to appear in the images. You can also use some special keywords, all of
which begin with the percent symbol (%). The keywords are replaced by VRay
with the corresponding value:
| Keyword |
Meaning |
| %vrayversion |
the current version of VRay |
| %filename |
the name of the current scene file |
| %frame |
the number of the current frame |
| %primitives * |
the number of unique intersectable primitives generated for
the current frame* |
| %rendertime |
the render time for the current frame |
| %computername |
the network name of the computer |
| %date |
the current system date |
| %time |
the current system time |
| %w |
the width of the image in pixels |
| %h |
the height of the image in pixels |
| %camera |
the name of the camera for this frame (if rendering from a
camera, empty string otherwise) |
| %<maxscript parameter name> |
the value of any VRay parameter, given its MaxScript name
(see section on MaxScript) |
| %ram |
the amount of physical memory (in KBytes) installed on the
system |
| %vmem |
the amount of virtual memory (in KBytes) available on the
system |
| %mhz |
the clock speed of the system CPU(s) |
| %os |
the operating system |
| |
|
* An intersectable primitive is a primitive that
provides a direct method for intersection with a ray (such as a
triangle, the infinite plane generated by a VRayPlane plugin etc). Most often, the number of these primitives is
the same as the number of triangles (faces) processed by VRay for the
current frame. Note that this may be different from the total number of
triangles in the scene. With the dynamic raycaster, only geometry that
is actually needed is generated and accounted for. Geometry that is not
generated is not included in this count.
Font - this button allows you to choose a
font and font attributes for the text in the frame stamp.
Full width - when this option is checked,
the frame stamp will take the whole width of the image, otherwise the stamp
will be only as wide as the text is.
Justify - specifies the position of the
stamp:
Left - the stamp is placed on the left of
the image.
Center - the stamp is centered.
Right - the stamp is placed on the right
side of the image.
Object Settings / Light Settings
These buttons bring up the dialogs for the
local
object and light settings.
Presets
This button brings up the
presets dialog.
VRay log
These
parameters control the VRay messages window. During rendering, VRay writes
various information in the file C:\VRayLog.txt. The messages window shows
some of that information so that you can view it without the need to
manually open that file.
Each message can fall into one of four categories, which are colored in a
different way in the messages window. Those categories are errors (colored
in red), warnings (colored in green), informative messages (colored in
white) and debug messages (colored in black).
Show window - when this is turned on,
VRay will show the messages window at the start of every render.
Level - this determines what kind of
messages will be showed in the window:
1 - only error messages
2 - error and warning messages
3 - errors, warnings and informative
messages
4 - all messages
Log file - this parameter determines the
location and the name of the log file. The default log file is C:\VRayLog.txt
Other parameters
Check for missing files - when this is on,
VRay will try to find any missing files in the scene and will put up a
dialog listing them, if there are any. The missing files will also be
printed to the C:\VRayLog.txt file.
Optimized atmospheric evaluation -
normally in 3dsmax, atmospherics are avaluated after the surface behind them
has been shaded. This may be unnecessary if the atmospheric is very dense
and opaque. Turning this option on will cause VRay to first evaluate the
atmospheric effects, and shade the surface behind them only if the
atmospherics are sufficiently transparent.
Low thread priority - turning this on will
cause VRay to use threads of lower priority when rendering.
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