[cecofuli]

VRay 1.5: THE COMPLETE GUIDE

REVIEW

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SUMMARY


INTRODUCTION


VRay 1.5: The Complete Guide


CHAPTERS 1 CHAPTER 2
Introduction and the broad history of computer graphics

CHAPTER 3 e CHAPTER 4
The Renderer

CHAPTER 5
Materials

CHAPTER 6
Cameras and Lights

CHAPTER 7 e CHAPTER 8
VRay Object, Environment e Render elements

CHAPTER 9
Updates

BEYOND VRAY, ITS COMMUNITY


CONCLUSIONS


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Messaggio modificato da cecofuli il 03 settembre 2008 - 09:39

[cecofuli]

INTRODUCTION
It was 1957 when Gio Ponti, on the occasion of the compilation of his work: “ Architechture is a crystal” , wrote: “ Light acts out shapes, freezes out the insights of dimensions and distance because of its absence of depth, it smashes in two some unities creating illusory appearances, it kills and changes weights, substance, volumes, proportions: light which was, once, just a flame to be isolated, by itself, so that it might not burn out, now runs where we want it to.”

Fifty years are passed, and light runs more and more “where we want it to”. The pre-sight techniques allow us to sense spaces (vibrations) that we project with absolute accuracy.

In the last five or six years many rendering engines have appeared. Others, such as the renowned Mental Ray, have been greatly improved and perfected. Some time ago a renderer was not much more, exceptions granted, than the appendix of modeler; today the situation is radically different.
Software such as Splutterfish Brazil, Cebas Finalrender and Chaosgroup VRay, in an extremely brief span of time, have managed to conquer incredible recognition both in educational areas and in the field of both large and small scale production. A real boom for the CG industry.
Developers are interested in investing in rendering engines. Wide scale users are more and more concerned with finding an easy-to-use product, which guarantees results as close as possible to photorealism. The last chapter in this innovative process, which is far from the terminus, are the so-called unbiased engines, amongst which the most well-known are Maxwell Render and Fryrender.
What may seem like a merciless battle between software houses, has layed down the conditions for new operative needs. The diffusion of a software has a potential which is greater in proportion to its training resouces. In a similar scenario, it may seem bizzarre that a publication such as the one which has been reviewed here can appear on the market thanks to the completely autonomous initiative of a young engineer from Bergamo, Francesco Legrenzi, who has created a Complete Guide of over a thousand pages, all dedicated to VRay.

Messaggio modificato da cecofuli il 08 settembre 2008 - 10:21

[cecofuli]

VRay 1.5 - THE COMPLETE GUIDE

It would, to say the least, be assuming to attempt to summarize two years of work in a few lines, and thus in actual fact it goes beyond the possibility of any possible general judgement. The field of computing requires manuals to make use of accurate and specific terms, as the speed with which the following versions of the software obliges manuals to use terms of a precise specificity, imposed by the rapid obsolescence of the following software versions. Nevertheless, the Complete Guide by Francesco Legrenzi takes its place on the virtual bookshelves of treddi.com without offering reference points.
It is in fact an editorial product which represents an absolute novelty, and not just as an Italian publication.


Fig. 01

There are many new features introduced by the Guide, but two essential main factors stand out in particular.
As opposed to volumes that one usually encouters in bookshops, Legrenzi does not focus on one single software, but rather decides to thoroughly examine the components of a single rendering engine, V-Ray, which is, moreover, not integrated in any commercial offering.
The decision to describe every single option of every rollout could remind one of a typical guide for an official course. With a browse of the thousand pages under the sobre black bookcover, sealed by the unmistakable logo of this Chaos product, one realises that this is not the case. The Guide does not limit itself to a mechanical scanning of software contents organized in an orderly and accurate index; it also provides detailed explanations and illustrations regarding all the concepts at the base of every single subject. The author finds a compromise between the subject and content, connecting in a sometimes obsessive manner the theory behind each feature with the explanation of the conseguent proper use.
The reasons for the author's choice are easily intuitable. A “command by command” guide would have produced a limiting result, whereas an esclusively practical formulation based on a series of tutorials, would have made it impossible to satisfy all the subjects that each user seeks. Legrenzi introduces color mapping with a vast preamble on colorimetry or presents light sources only after having briefly explained the basics of illuminotechnique, handing over to the reader a series of information organized according to various levels of depth. This treatment of the subjects is thus extremely useful for the novice, who can then learn step by step the key concepts of any renderer, but it is not less useful for a professional, who can look up the single command for a quickly consultable summary in order to quench any doubts about any parameters which require a configuration in multiple steps.

Messaggio modificato da cecofuli il 08 settembre 2008 - 10:21

[cecofuli]

CHAPTER 1 and CHAPTER 2
Introduction and The history of computer graphics



In taking a brief look at the contents of this publication, the first thing that catches one's eye is the first section of 150 pages, dedicated to introductory subjects, where we find the presentation of the VRay rollouts and a personal investigation by the author regarding the fundamental milestones in the history of computers and computer graphics, organized stricly in chronological order.


Fig. 02 - The first chapter briefly describes the VRay rollouts graphically. In this image the development of VRay materials.


It is important to emphasize how the divulgative character of these accessories helps one to acquire a general perception with regards to the times and modalities of software and hardware development, although this is not expressly part of the specific learning process which the guide pre-establishes. This is an added value which improves one's general knowledge of the subject which should not be limited merely to the utilitarian aspects of one's work tools.


Fig. 03 - Intriguing machine for carrying out automatic additions and subtractions, the Pascaline. The second chapter flings the reader into a science documentary atmosphere, where important figures from various epoques make their appearance, from Galileo to Dieter Morgenroth, maker of a recent plugin of the parametric for VRay.




Fig. 04 - Even though the guide is based on the version for Autodesk 3ds max, reference made to more recent implementation for other software is not missing. This is the case of Rhinoceros, whose plugin has been developed by ASGvis.

Messaggio modificato da cecofuli il 08 settembre 2008 - 10:19

[cecofuli]

CHAPTER 3 and CHAPTER 4
The Renderer


Once our curiosity has been aroused by the smooth approach that the author has chosen to adopt in the first two chapters, we find ourselves directly lead into the heart of VRay. Its renderer.
After a brief and accurate description of the Frame Buffer and of the Global Switches, the paragraph is dedicated to VRay: Image sampler opens illustrating the general principles of antialiasing, later describing the sampling systems used by VRay, comparing them in a well accurate series of tests, focusing attention on the greater efficiency of one method compared to another, given a certain situation. Equal attention is given to filters, and from their analysis many very interesting aspects emerge, especially as far as rendering times are concerned.


Fig. 05 - Antialiasing is one of the more macroscopic aspects in the effects of rendering. In order to reach the best compromise between speed and quality requires great effort and confidence with the parameters. The guide, by means of illustrated tests, synoptically analyzes a great variety of situations. The image refers to various situations of undersampling of the Adaptive Subdivision Sampler.


The paragraph dedicated to VRay: Indirect Illumination conferms the excellent preparation and high interest of Francesco Legrenzi for a subject which is of fundamental importance for any user, whatever the chosen field of application for the renderer. After a brief introductory explanation describing the principles of global illumination, the author moves on to accurately describe all the calculation methods of VRay, analyzing each of them singularly and in combination between each other with extremely specific tests. Each example demonstrates its result without leaving out the theorical notions at the base, with constant reference to advantages and disadvantages according to various classifications.


Fig. 06 - This image will look familiar to treddi.com users. It is in fact the scene used by Francesco Legrenzi (cecofuli) for a tutorial on the Irradiance Map, still present in the dedicated section of the forum.


It is an obvious act that most VRay users apply the renderer from Chaos Group in the field of architecture. A huge mass of architects, engineers and designers press F9 every day without actually knowing what they are doing. If the average level of visualizations has greatly risen, this is mainly due to the fact that rendering engines are able to produce good GI effects and chromatic rendering even just with default parameters, rather than thanks to the operator having truly mastered the system. It is fundamental to truly grasp the use of the single parameters if one wishes to solve complex situations in time spans which are realistically compatible with production needs, which is an extremely different context compared to individual experimentation .
The Complete Guide acts in support of every aspect of architectural production. Indoor and outdoor scenes are analyzed in order to understand which are the characteristics of the various combinations between the calculation methods of the GI, whether it is a simple static image or an animation, thus various suggestions are made for resolving problems regarding calculation durations and flickering phenomena and handling them with awareness.


Fig. 07 - Often the IM+LC association method is found to be more convenient in terms of rendering quality/time.Nonetheless in particular situations, other methods can guarantee preferable results. So it is preferable to reason by single objectives each time one proceeds to setup a scene for rendering.


After an intensive course on Indirect illumination, we turn page and change chapter. We find less complex (from the point of view of the explanation) subjects waiting to greet us, but in any case very important for the configuration of a scene. Some of these are VRay: Environment and VRay: rQMC Sampler and VRay: Caustics. These paragraphs are extremely easy, clear and well explained, which give the reader a sense of calm before the storm, which breaks out soon enough in VRay: Color Mapping.


Fig. 08 - The comparison between various methods of use of the VRay Environment highlights operative aspects which are rather interesting and focus on issues which are often underestimated. For example the difference in terms of rendering time between the two HDRI images used in this test on GI generating.



Fig. 09 - A caustics test.



Fig. 10 - In the image we can see a summary of the situations derived from the varying of the parameter Adaptive amount, present in the rollout VRay:rQMC Sampler. This part of the guide cites interesting anecdote about the the Monte Carlo algorythm, the use of which is widespread as much as its origins are ignored.


Citing a passage of the Complete Guide, we rember how “The reason for the presence of various methods of color mapping in VRay is that of being able to modify the rendering as would happen in an ordinary camera.”. The author thus fulfils a vast preamble regarding float number images, light and colorimetry. Contributions on linear and non linear perception, the characteristics of colour spaces in digital domain and ICC profiles are fundamental in order to master any aspect of production. These subjects are often taken for granted or in any case ignored in many treatments, because of the fact that they are subjects which are non intrinsically inherent to the specific matter, but generical subjects for any type of graphic production.
The choice of providing a wide support on the issue of digital color appears with the precise aim of giving the non-experts all the tools necessary to understand the basic principles of Linear Work Flow and to perceive, as a whole, what varies when intensity and gamma parameters are modified in VRay:Color mapping.
This contribution, considering the complexity of the subject, happens to be one of the most useful in the Complete Guide. Especially for the more careful reader, who wishes to obtain the knowledge for a correct handling of colour and is not satisfied with a merely discreet level.


Fig. 11 - In this case, the concepts of linearity in acquisition and non linearity in transmission from a photocamera are visually expressed. The phenomenon in this case is described by means of the curves in Adobe Photoshop. Colour handling is a traditionally tricky subject for novices or for whoever, even if for a long time, has been carrying out rendering without having a true knowledge of the theorical basics of digital colour. The Complete Guide attempts to enable the understanding of this matter as much as is possible.



Fig. 12 - Comparison between two modalities of color mapping of VRay: Gamma correction and Intensity gamma. This shows how the second method is aimed at preserving original colours of the models.

The seemingly unending explanation regarding the renderer thus concludes, but not without having analyzed VRay: Camera, VRay: Displacement and VRay: System. Also in this case, there are in-depth explanations which escape the cold listing of parameters in the narrow sense. Particularly useful are the parts where VRay's properties of system RAM usage are described, providing the reader with the knowledge necessary to manage his own scenes, optimizing rendering time without bumping into problems due to lack of memory.


Fig. 13 - A lot of attention is given to parameters often and willingly ignored by the average user, such as those concerning VRay: Camera rollout. In this example the Height parameter is being examined.



Fig. 14 - VRay's displacement features include various aspects which can simplify and empower the use of this often fundamental function. Amongst these there is the possibility of correctly placing the physical height of the displacement on the basis of a formula containing a K constant, obtainable from the chart.



Fig. 15 - Graphic example, reconstructed by the author, of the Min Leaf system parameter, on the basis of data present in the VRay message. The correct management of the Max Tree and Min Leaf parameters can solve many problems regarding usage of system resources.

Messaggio modificato da cecofuli il 08 settembre 2008 - 10:18

[cecofuli]

CHAPTER 5
I materiali

Once the subjects concerning the renderer are over, we find ourselves more or less halfay through the book. The path is still long. We still have five hundred pages and many contents. We are still missing the complementary aspects: for a start, the materials. The remaining chapters are setup similarly to those treated until this moment , as the author, albeit in the wake of such different subjects, tries to mantain a narrative coherence aimed at not letting the reader feel lost. We will try then to understand, through a series of images taken directly from the book, how theComplete Guide faces VRay's seven shaders and VRaymap's relative ones.


Fig. 16 - The blurred reflections can be calculated in direct or indirect ways. The comparison between two methods, different in calculation times and configuration complexity, is deepened in the usual series of tests. The particular attention to technical aspects is to be noticed, such as the coherence between the min rate/max rate shader configurations with those of the Irradiance Map and many other tips, useful for not running into error which would otherwise be frequent.



Fig. 17 - The coherence of VRay is underlined every time homologous subjects are faced. This is the case of VRayMtlWrapper, which refers directly to the setup of the VRay object properties. Taking these factors into account makes scene configuration easier and faster, enabling one to maintain a certain order, which is essential when one intervienes a second time on a job.



Fig. 18 - The paragraph regarding VRayLightMtl faces all the possibilities offered by this incredibly useful shader, amongst which the use of TextMap.



Fig. 19 - VRay2SidedMtl is often neglected, but allows one to obtain translucency effects with few and simple moves. The Complete Guide, as in the illustrated case, lists a few simple configurations needed to obtain decent results.



Fig. 20 - VRayBlendMtl is analyzed with a comparison with the material Shellac of 3ds max, in order to underline analogies and major potential offered regarding the simplicity of management. Shellac material and the Blend of 3ds max material are appropriate to explain the concept of mathematical representation of colours.



Fig. 21 - The distinction of channels in VRayOverrideMtl.



Fig. 22 - By means of the ease of its configuration, VRayMap is often an appreciated short cut. The dedicatd paragraph exemplifies the analogies with parametrs to be found in VRayMtl. This is the case of Fog color, this time described through the variation of the Fog Multiplier.



Fig. 23 - Rapid walkthrough on the making of a HDRI map. The Completa Guide faces the main differences between HDRI and LDRI, illustrating the effects of their use in channels of environment. Lastly configuration of VRayHDRI map parameters are treated in detail.



Fig. 24 - The VRayDirt map is known for its use in ambient occlusion simulation. As well as understanding the concepts at the base of its traditional use, that is GI simulation, the Guide explains the other advanced possibilities, such as the possibility of mapping the inverse of the occluded color. These are less known aspects, not often used but useful to know.



Fig. 25 - Adeguate blending setup configurations allow us to use the VRayEdgeTex map obtaining direct results otherwise only obtainable after a laborious phase of post production.



Fig. 26 - Use of theVRayBmpFilter map, combined with the VRayDisplacementMod, allows one to obtain a high level of detail even using a mesh of very few polygons. It is a fundamental implementation, especially in the field of games development, given the enormous pontential offered by sculpting software such as Zbrush in the generation of displacement maps.



Fig. 27 - The chance to fulfil mathematical operations with colors is essential in the viewpoint of compositing. The VRayCompTex map allows one to manage them through seven operators (Add, Subtract, Difference, Multiply, Divide, Minimum, Maximum) explained by the Complete Guide with examples which explain the differences between them.

Messaggio modificato da cecofuli il 08 settembre 2008 - 10:14

[cecofuli]

CHAPTER 6
Cameras and Lights

With the introduction of the physical system, VRay has filled an obvious gap which downgraded it compared to other last-generation rival softwares, in particular the Maxwell Render one. The features of the cameras and the lights which the version 1.5 Final of VRay owns allow one, by now, to manage a virtually infinite amount of situations, with settings sometimes clearly moving away from the original elements of 3ds Max, but with which the render deals very well. Apart from considering some rare cases which might generate undesired effects.
In this case as well Francesco Legrenzi decides not to take anything for granted.
A thorough digression concerning the theory of photography precedes the part devoted to the cameras. It is a very didactic kind of information, organized in such a way to provide a basis about the management of the cameras of every software, with a special care to the VRayPhysicalCamera, whose functioning is essentially very similar to the one of a real camera.


Fig. 28 - Examples showing situations took with different shutter speeds. The Complete Guide contains dozens of images summarizing the functioning of a real camera.



Fig. 29 - A special care is devoted to the depth of field and the concept of focal length.
[Reduced image: 91% of the original image.



Fig. 30 - Chapter 6 examines all the parameters of the VRayPhysicalCamera, one of the most powerful tools of the Chaos Group’s software. The counterbalance of the white allows one to correct the color directly in the rendering, as happens with real digital cameras.


The author devotes the same care to the VRayLight and the VRayShadows, which are introduced by a thorough description of the illuminating engineering, reminding us, with a bit of melancholy, the long winter afternoons spent in preparing the exams of Technical Physics.


Fig. 31 - All the principal softwares nowadays allow the implementation of IES sources of light, characterized by having the same properties of the catalogue products really available on the market. This represents a very powerful union. If a certain mastery is used, these sources allow one to obtain a very reliable simulation of the lighting of environments one wants to previsualize. Therefore, having good notions of illuminating engineering is not just useful, but often essential.


The chapter ends with the description of the VRayLight and VRaySun - VRaySky parameters.


Fig. 32 - The three possible morphological configurations that a VRayLight might assume. In the case of the Dome Light, the main differences with the SkyLight of VRay are shown.



Fig. 33 - In case one decides to use a unit of measurement for the VRayLight different from the default one, the multiplier returns a different value. It is just a conversion factor. The Complete Guide deepens these facets providing the conversion formulas so that one can disentangle among different units of measurement.



Fig. 34 - The same scene is used for several deep tests in order to clearly explain the functioning of the parameters of the VRaySun source. In this case the aim is to emphasize the variation in the effects due to the change of the turbidity parameter, with the VRaySun activated or deactivated.



Fig. 35 - As for the VRaySky, the guide uses the same scheme adopted for the VRaySun. In fact many parameters coincide and are strictly related one to the other.

Messaggio modificato da cecofuli il 08 settembre 2008 - 10:11

[cecofuli]

CHAPTER 7 & CHAPTER 8
VRay Object, Environment and Render elements

The seventh chapter inspects those specific features of VRay which do not fall into any category included in the objects of the previous parts of the volume. It is referred to VRay Objects and specific terms of VRay which are included in the section dedicated to Environment effects.
Amongst the VRay Objects we find very powerful tools such as VRayProxy and VRayFur and other very useful ones like VRayPlane.


Fig. 36 - The phases of importing a .vrmesh through use of the VRayProxy object. A powerful and user friendly tool. Essential for the management of greatly extended scenes, which present elements which have a high degree of repetitivity. This is the case of outdoor scenes with large presence of vegetation or other models characterized by mesh which are very rich in polygons, which if not used as proxies would certainly cause problems regarding system memory usage.



Fig. 37 - Synoptic presentation concerning different configurations of the number of VRayFur segments, in order to analyze the resulting detail and above all the rendering time.



Fig. 38 - The Complete Guide goes into detail about VRayFur showing some very interesting features. This is the case of filmaments variations obtained thanks to the use of a procedural map.



One of the most interesting features of VRay is definitely VRayToon. Based on the concept of non-photorealistic rendering, typical of plugins such as FinalToon or Illustrate, VRayToon is basically a very simple-to-configure outliner, which has the big advantage of allowing one to implement any geometry supplied by VRay in the rendering.


Fig. 39 - The image demonstrates how VRayToon is able to manage elements which are very different to each other without any problem, like for instance VRayFur, Displacement, trasparencies, reflections also in the case of very complex mesh. The flexibility of VRayToon, its user friendlyness and the relative rendering speed make it a tool that, whilst incomplete compared to other plugins on the market, permits excellent results.


The last part of the book enters into the specifics of compositing. Chapter seven introduces the subject by illustrating VRaySphereFade, and sums up the general concepts which are at the root of compositing, both for the basic instruments supplied by VRay, as well as the specific software present on the market today (some names will certainly sound familiar, for example After Effects, Shake, Fusion, Combustion, Nuke, etc...).

The eighth chapter proceeds with matters concerning compositing. It now focuses on VRay Render Elements, which exploit the qualities of the Render Elements system directly in 3ds max. The elements allow the creation of separate rendering for each selected pass, useful for building the base for the following compositing process. The power of this production system lies in the fact that if one modifies one pass, one will not have to carry out the rendering over again, but it is enough to modify the images obtained with the compositing program in use.
This work flow can be applied with many methods. The Complete Guide analyzes them, explaining which are the main points in favour and against each of them, as well as presenting and describing all the VRay Render Elements.


Fig. 40 - Example of compositing of a VRayRawShadow channel and a VRayRawLighting channel, by means of a algebric sum of the layers. The particularity in this case is given by the fact that because of one being the exact opposite of the other, any shade present will disappear. The Complete Guide presents an amazing amount of cases to be found in compositing, and awakens curiosity also in those who have never approached post production, and gives them the basic elements to be able to venture into this area of production.

Messaggio modificato da cecofuli il 08 settembre 2008 - 10:09

[cecofuli]

CHAPTER 9
Updates

The draft of the volume began based on version 1.47, a milestone in the history of this software because of the importance of the new elements introduced when it came out. In the two years of work which lead to its release, clearly Chaos Group have not been twiddling their thumbs, but have continued recently released works with version 1.5 FINAL and included service packs.
In order to not have to constantly modify the draft of the manual, the author has preferred to add an extra chapter where all the recent modifications worthy of note introduced in the later versions. This information is essential both for a question of completeness, in relation to the large amount of contents in the Complete Guide, and also in order to leave a door open to further future updates which may be needed if the work were continued in later editions.

Messaggio modificato da cecofuli il 08 settembre 2008 - 10:07

[cecofuli]

BEYOND VRAY, ITS COMMUNITY

Today the market offers a wide variety of rendering engines. The key behind VRay's success, is beyond its certain intrinsic qualities, and lies also in the renowned official forum, where every day many users flock to share their experience. Confronting and comparing with the user is, for the developer, an element that cannot be ignored, most of all in the 2.0 web viewpoint. At the same time software evolves extremely rapidly. At the beginning of 2008 secrets are no longer jealously protected in workshops. These computer science "Medieval" realities, which have long allowed speculation, are inch by inch becoming far memories. To improve, even the best cg artist can't forgo the comparison, real or virtual, with other users. Everybody can take advantage of this kind of opportunity, which is moreover supported by the incredible mean level boost of the visualizations present in these last months.

Legrenzi's Complete Guide goes beyond the traditional way of conceiving a handbook, which is limited in its possibility of interaction, and takes notice of the surrounding reality, and offers an innovative tool thanks to a direct channel with the users assigned on treddi.com, the website of reference for Italian CG, with more than 30000 registered users. After having registered to a private section, dedicated to users of the Complete Guide, they will be able to share a unique experience with the author,discussing about the contents of the book and about specific problems.

Messaggio modificato da cecofuli il 08 settembre 2008 - 10:07