Other think there is no any magic and all you need is the long and difficult work with the renderer parameters for each new scene. That firstly you need to run the rendering in a test mode, with the visible samples of the V-Ray sampler on and, by a sample map, long and boringly try the optimal settings to soften and eliminate aliasing; to loose the much time for trying than to start the competently tuned rendering. Then to begin the Irradiance map calculation with the enabled Show calc. phase option and to look intently at the Irradiance map sample passes, supposedly controlling the calculation process and many other shamanistic superstitions.Curiously enough, but there are no really universal one-size-fits-all setups. Like, actually, the separate settings for interior and exterior as well. But, there are some hints and tricks, which you will learn from this tutorial and there is nothing difficult in them and they all will be explained.
At first, we have to make clear that there are starter settings, that may be beginning of the any rendering, for not to draw our attention each time to any possibly incorrect options. We got to fully concentrate on the actual scene setup. Only in some situations, when the rendering has some parasitic artifacts, we need some slight tuning to get rid of them. This is true not for V-Ray only, but is an absolute concept for any rendering application. To tell the truth, the correctly set lighting with a good scene geometry almost never give the unwanted surprises on the rendering, and in most cases you don’t need to set anything but final resolution.
Click the ellipsis (…) button near the Production and near the Material Editor (if the lock button is released) and choose V-Ray from the showed list.
The screenshot of the V-Ray:: Frame Buffer rollout of V-Ray tab that is in the 3ds Max Render Scene window. Here present the three options and the one Save as Defaults button. The options are Production, Material Editor, and ActiveShade.
V-Ray Frame Buffer rollout
In addition, it is important to leave active the Get resolution from MAX function. This step can free us from the need to constantly go to the V-Ray tab, rollout V–Ray:: FrameBuffer and set there a needed rendering resolution.
The screenshot of the V-Ray:: Frame Buffer rollout of V-Ray tab that is in the 3ds Max Render Scene window. Here present the two options: Enable built-in Frame Buffer, Render to memory frame buffer; Show last VFB button; and three sections. They are the Output resolution with the Get resolution from MAX checkbox, V-Ray image file and Split render channels.
V-Ray Global switches rollout
V-Ray Image sampler (Antialiasing) rollout
Fixed image sampler, Adaptive DMC image sampler and Adaptive subdivision image sampler V-Ray antialiasing methods
Fixed is the simplest algorithm, which is roughly selects color samples relating on the sub-pixels colors, without any adaptivity. Its only option is Subdivs and it determines the number of pixels subdivisions, which will determine the final pixel color. The number of used sub-pixels is equal to the square of the Subdivs value. Fixed rate sampler is a brute force that has no adaptability in the calculation of the number of subpixels needed to form pixel colors. This algorithm calculates each case of AA with the same care, regardless of conditions. Therefore, this algorithm should be applied only in special cases, when the scene have number of DOF or blur effects, highly detailed textures and fine details, on which artefacts appear, from which you can not get rid of in any other way. Sometimes it happens that the calculation of adaptability of other algorithms may take longer than calculation with a fixed value. However, in other cases, for the lack of adaptation to the conditions, we have to pay by big time rendering when using the Fixed image sampler.
Adaptive DMC in essence is the same as Fixed, just with adaptability. The essence of his adaptability is the automatic determination of the required number of subpixels for each pixel separately, rather than use a fixed value, as in the case of the Fixed rate sampler.
Adaptive DMC sampler may be applied in the same cases as Fixed, but when the scene has less problematic areas. This will save time rendering at the same level of quality, as that is with a fixed number of subpixels. In some cases, the Adaptive DMC sampler turns out to be even faster than the more technologically sophisticated Adaptive subdivision sampler, which will be discussed a bit further. For example, that is in some scenes with Motion blur. However, is not true for all scenes and finding of its benefits can only be done experimentally. Such experiments on changing the filter and selection of best option would be justified only by the multiframe animation setup, where each additional minute of rendering of each frame can result hours or even days in result.
Adaptive subdivision is the most advanced adaptive anti-aliasing algorithm in V-Ray. Its main difference from the Adaptive DMC algorithm is a possible to use not only the supersampling, but also the undersampling on unimportant parts of the generated images, thus saving the lion’s share of antialiasing computing time. Min. rate and Max rate parameters determine the minimum and maximum values of undersampling and supersampling. These values determine the number of samples, i.e. color samples used to determine the color of produced pixels. In particular, if the rate setting is -1, it means that to calculate the color of the four (!) neighboring pixels the one sample is used. A value of 0 means that each pixel uses one sample, and the value of rate, equal to 1, means that for determining the color of one pixel, the four samples are used, etc. Mathematically speaking, the rate value is the power of the number 4 in the final number of subpixel samples of a particular pixel color of the rasterized vector shape. The Color thresh. parameter is responsible for automatic selection of the desired Min. rate and Max. rate, as in the Adaptive DMC sampler.
Another feature of the Adaptive subdivision sampler is the presence of additional parameters that control the automatic selection of the needed Min. rate and Max. rate. These are the Object outline and Nrm tresh. Where Object outline controls the quality of antialiasing on the borders of the object – namely, using the maximum Max. rate supersampling value, and Nrm tresh. enhances the quality of sampling within objects, depending on variations in the direction of adjacent normals, that is, small and sharp details on the object.
Randomize samples function allows you to randomly change the location of anti-aliasing samples. Nominally they are on a strict grid-like pattern. While smoothing the horizontal or nearly horizontal, and vertical or nearly vertical lines on the visualization, the strict periodic arrangement of samples may lead to parasitic straight or step-like bands. To avoid these artifacts, it is sometimes useful to do color sampling slightly chaotic; it is for this purpose Randomize samples setting is needed for. Illustrative examples of how render engine behaves with the turned on or off Randomize samples, you can see at Image samplers examples: Randomized antialiasing.
The Randomize samples option in universal V-Ray settings should be left active.
Additional information on the purposes of the other Image Sampler (Antialiasing)parameters may be found in the corresponding V-Ray Help section.
Adaptive subdivision sampler is the most flexible, most technologically advanced algorithm of antialiasing used in V-Ray. It gives the greatest computing speed with the best quality of the image. That is it should be used as AA (AntiAliasing) default algorithm in universal settings of V-Ray. Only if there are artefacts on the fine details, and they are not removable by other ways, the less adaptive and less flexible Adaptive DMC or even a rough Fixed algorithm should be used.
Despite the existence of special algorithms that reduce the effect of aliasing, in practice, the most preferred and rational choice is NOT to increase the number of subpixels by banal raising high the AA settings. But to decrease an aliasing by increasing the resolution of the final image while using the slight AA. The essence of this trick is that when the resolution is decreasing, the relative aliasing jags are also getting smaller, and a slight AA removes them. High resolution and a small amount of AA give excellent results, far surpassing the ones, which can be obtained by simply overstating the parameters of AA. But the most interesting thing is that the calculation in high resolution, at least a half times greater than required, would take less time than rendering the image of the same quality, but initially with the required resolution and high AA settings.
It is so appropriate values of Adaptive subdivision sampler are the ones that are set in it by default. That is why in the universal V-Ray starting configuration they should not be changed by overstating or understating. They must be left as they are initially.
V-Ray renderer supports almost all standard filters of 3ds Max.
When the Image Sampler calculated the required amount of sub-pixels, the next process is the conversion of information to pixels. Color of the pixels can be formed immediately by averaging the color of all samples, belonging to a particular pixel, or filtered by a special algorithm that makes a certain adjustment in the formation of pixel colors from the subpixels. These algorithms are the antialiasing filters.
To select one of the filters is sufficient to mark the checkbox On and select from the drop down list the desired AA filter.
3ds Max has many filters with different algorithms. The most popular, and even causing “holy wars” among beginners and even experienced visualizers, are the Catmull-Rom and the Mitchell-Netravali, named after the developers of current algorithms.
These wars do not cease to this day, stirring up the violent disputes about which filter is better and which of them should be used for their renderings.
With the application of Catmull-Rom or Mitchell-Netravali filter, the received image becomes little sharper, as if view focuses a little on it.
For example, Catmull-Rom filter makes very sharp edges of objects, sometimes thus improving the general form of rendering, but it is not significantly affecting their internal parts.
So, if you want to raise up the sharpness, for example in Photoshop, to the entire image including the inside of objects and not just at its edges, the unwanted defects in the form of ultra-sharp boundaries of objects may appear, what will look unnatural and ugly.
Another very significant problem of AA filters is that they work in RGB space only, unable to perform properly rasterization with HDR-rendering. Performing the calculation of pixel color from the sub-pixel floating-point information, the computation errors arise and they seen as awful artifacts. They are distinctly visible on the borders of bright objects, for example on objects with VRayLightMtl materials or visible light sources, such as VRayLight. Moreover, another defects, which even more depressing – the reflections of those bright lights on the reflecting materials in the form of evident black borders around reflection spots.
Applying the AA filters greatly reduces the freedom of post-processing of the image, making it impossible to have high quality sharpness of desired extent manually.
In addition, the filters that add sharpness on the edges of objects, very amplify the spurious moiré effect, even at high settings of an Image sampler.
It is for these reasons we should not use AA filters at all. Only in some cases, such as animation, where there is no possibility of adding sharpness to each of hundreds of frames by your hand, the use of AA filters is justified.
V-Ray Environment rollout
This rollout has important for rendering options that allow us to substitute GI glow of the environment, the reflection/refraction, and the refraction separately. These are the GI Environment (skylight) override, Reflection/refraction environment override and Refraction environment override parameters respectively.
Suppose we want to render a car in the exterior scene, and we want its body to mirror the clouds and surrounding buildings. All we need is to put into the Reflection/refraction environment override slot the corresponding spherical or cube map with the desired image and it will be reflected on the body, or rather on all reflecting materials, of the car. For more information on the panoramic and cubic maps, visit the Making of irtual 360 panoramas.
The same can be done with global illumination of the scene.
Global light may be a simple fill lighting of one solid color, bitmap RGB or HDR map.
Anyway, it is the feature of the some particular scene and the goals that its creator, so all the parameters of this rollout in universal V-Ray settings should be left intact, and changes needed only in special cases.
V-Ray Color mapping rollout
There are the parameters responsible for the rendering exposure and gamma correction in this rollout.
Exposure is a term that came to computer graphics from photography. The exposure means the amount of light, which fell on the film during the shooting of photo. Photo can be well exposed, i.e. look good, underexposed – to be too dark and dull, and overexposed – to be overly bright. In computer graphics exposure means roughly the same thing – namely, the brightness and color saturation of generated images.
Gamma correction is a necessary correction and rendering images with a certain degree of nonlinearity of the gradient tones from dark to light. This feature is inherent to modern color information transmitting and displaying systems. This aspect can be controlled in the Color mapping of the render-engine V-Ray.
V-Ray has many exposure control algorithms. They are Linear multiply, Exponential, HSV exponential, Intensity exponential, Gamma correction, Intensity gamma, and Reinhard.
The most popular of these are the Exponential and Linear multiply.
Exponential Color mapping algorithm outputs the brightness values of all image pixels exponentially. Its essence is that the illumination of the scene appears nonlinearly, with a little brighten of dark areas and darken very bright ones, so averaging the overall result, trying to display all levels of brightness in the limit of RGB colors. This algorithm allows to get rid of darkness and, at the same time, to eliminate overexposure of very bright areas, such as visible light sources or flashes on the scene geometry from them.
Another feature of an Exponential algorithm is that the color saturation of pixels is calculated based on their brightness.
In practice, this algorithm results very faded and unsaturated images, satisfying the necessary level of photorealism and presentable only in rare cases.
As a rule, Exponential Color mapping can be suitable only for some interior renderings, where undertones are more important, rather than specific colors of individual objects.
It is because of dullness and desaturation of the image, Exponential Color mapping completely unsuitable for presentable product rendering, where the representing for each color of the object, bright and saturated as much as possible, is important. For such rendering, the Linear multiply Color mapping algorithm is much better.
Linear multiply Color mapping algorithm is a linear algorithm that multiplies the each pixel color on its brightness. Thus, we obtain a linear, bright and vivid picture.
However, because of its linearity, the use of this algorithm leads to strong and sometimes horrible overexposure in bright areas of the generated images, making it very unsuitable for middle-tone interior visualizations.
Theoretically, to correct the defect of Exponential Color mapping algorithm, namely the colorlessness of an image, and to approach saturation of the Linear multiply Color mapping algorithm, the HSV exponential algorithm was designed. However, in practice, it remains just as uncomfortable as the Exponential or Linear multiply Color mapping ones.
There is another, not very popular, especially among beginner 3d artists, yet the most powerful and flexible algorithm for exposure control in the V-Ray, called Reinhard Color mapping.
Reinhard Color mapping is a hybrid algorithm, ideally combining in itself the other two basic algorithms: the Exponential and Linear. It is this algorithm is able to give not overexposed, without the “nuclear” overbrights, and at the same time rich and vibrant presentable images, making renderings truly photo-realistic and tasty 🙂
On the left is the Exponential, in the center is the Linear multiply, and to the right is Reinhard color mapping. Green rectangle on top of each example shows a sample of desired colors, which are in the Diffuse slot of a frog’s green VRayMtl material.
It is easy to see that the left image is dim and pale, and even specially backlit scene background looks gray instead of white, despite the fact, that in the Diffuse slot of its material is pure white RGB 255.255.255 color.
The middle image has a more lively appearance, the frog is bright and juicy, and the white background looks clean and white. However, compare the bright and oversaturated frog color with a rectangle sample. The disadvantage of this color mapping method is also obvious. Despite its richness, the picture turned out very overexposed.
Quite another thing is the right visualization. It looks nor dull, nor overexposed. The white background is really white. Look at the color sample; it exactly coincides with the color of the frog. This is precisely the result, which must be obtained. It is presentable and lively. Absolutely the same situation will occur at interior or exterior 3d rendering. This is thanks to the use of a good and adaptive Reinhard algorithm.
To work with this algorithm, it is necessary to find Type section in V-Ray:: Color mapping rollout, and select Reinhard from the drop-down list. This will make the control parameters of algorithm to appear.
Multiplier is a parameter that controls the overall brightness of the image. More about applying it, you can learn from the Replacement VRayPhysicalCamera by a Standard tutorial.
Burn value is the most interesting parameter of this algorithm. As mentioned earlier, Reinhard is a hybrid of two other algorithms. Exactly the Burn value determines how Reinhard will behave. If this parameter is zero, then Reinhard will give a result quite similar to Exponential Color mapping, if unity – similar to Linear multiply Color mapping. Intermediate values move the direction of the work of Reinhard closer to Exponential or to Linear.
Thus, by adjusting Burn, you can achieve excellent bright and intense visualizations, which Exponential cannot boast, at the same time to get rid of Linear’s overbrights.
In practice, the most suitable is the value of Burn value equal to 0.35. This value will be an excellent choice for most interior and exterior scenes, as well as for product renderings. That value should be used in universal settings of V-Ray.
Gamma is the parameter that allows us to perform gamma correction of the image.
The nominally universal value, suitable for any scene is the value of color mapping gamma equal to 1.8. That is it should be used in universal V-Ray settings.
Parameter Sub-pixel mapping determines where exactly color mapping will be applied, directly to the final pixels of the image or at the level of sub-pixels that are only after color mapping will be converted into pixels. This feature is recommended to be disabled even by developers of V-Ray, as in this case a more correct result can be achieved. However, this parameter is very useful when we want to render not to HDRI, but to RGB space. Its activation lets to get the satisfactory smoothed edges on the bright image areas, which come beyond the RGB space. Still, this parameter may be disabled for correct HDR rendering.
Clamp output allows clipping of the high values of brightness outside the RGB space. Sometimes it can be useful, for example, to get rid of artifacts of AA filter (see the example of the frog’s eye above) that may appear because of an incorrect work of the AA filter with HDRI. Also is to obviate the problems of AA smoothing when rendering images with dynamic RGB range.
Nominally correct is a rendering and saving the image to the HDR (High Dynamic Range) format, so in universal settings Clamp output option must be turned off, or else when image stored in HDRI, the complete information about the actual brightness of the pixels irreversible loses.
Clamp level parameter determines the level of the cut-off of the information by Clamp output function.
Affect background determines whether to apply color mapping to the Environment map or color. As a rule, if the override background image is set, it is rarely a need to apply to color mapping on it. Therefore, in the universal V-Ray settings, the Affect background function must be switched off.
There is a misconception that there is no any need to configure color mapping at all; that it is sufficient to render HDRI in a linear space and save it in the appropriate format of HDR; after that, using compositing in 2d editor, brush up the image to the desired gamma with the desired exposure. Unfortunately, it is not so.
Firstly, to render one exposure, and then tune it up to another is a blind work. To make a beautiful photo-realistic visualization, not seeing it, its details, colors, illumination, but focusing only on a rough preview with the unfair color mapping it is necessary to be at least a seer or prodigy, who can produce the desired exposure correction in own mind 🙂
Secondly, the adaptive V-Ray engine, based on the principle of the sampling the most important to the overall result values and cutting off the less important, will simply incorrectly calculate what image area is important and what is not. V-Ray, to save time and computing resources, produces less accurate calculations in dark places with low light energy, in consequence of what they will have a lot of noise. However, since they are still visually dark on the supposed image, then the noise is little or even not noticeable on that image, even when we closely look at it. At that time, the bright spots with high light energy are always in sight and V-Ray produces the most accurate calculations on them, so in bright places there are less of noise and artifacts.
Therefore, if the rendering calculated in gamma correction lower that it would later be observed in, e.g., with a linear gamma 1.0, the picture, after further correction to the bright 2.2 side, will be very noisy and contain many artifacts, as V-Ray considered that image initially as dark.
Nevertheless, the Don’t affect colors (adaptation only) function exists for such unusual requirements. The essence of this function is that it allows one to get an image in linear gamma of 1.0, but all the effects and GI are calculated as if they were in gamma 2.2. Thus, we obtain a linear image ready for further correction, but without the presence of the aforementioned artifacts inherent to the dark areas of rendering.
V-Ray Camera rollout
The last rollout of the V-Ray tab of a Render Scene window, is a rollout named V-Ray:: Camera.
This rollout holds the camera settings, namely, the additional features that enhance the standard 3ds Max camera. Such as depth of field, motion blur, switching types of cameras to standard, spherical, cylindrical, etc.
Of course, the universal configuration of V-Ray has no relationship to this rollout and there is nothing should be changed in it without a specific need.
Now you are a little more familiar with some important aspects of configuring V-Ray renderer.
We hope that reading this part of the tutorial makes you see that the previously seemed unfriendly or even challenging interface of V-Ray tab is much simpler and easier in fact. Also the knowing these basic functions makes your work with V-Ray much easier and professional.
About the functions and settings of next Indirect illumination tab read in the following tutorial.
All have easy settings and beautiful 3d renderings!
See you next tutorial, check for updates, and certainly support us by purchasing liked excellent premium 3d models 🙂 You can do it!
Your questions and suggestions about this tutorial feel free to write in the comments, and we respond to help you. Posted by NOMERADONA_ART .