Welcome to this V-Ray feature short demonstration.
In this video, we'll take a closer look at the V-Ray Denoiser. How it works, what
could be achieved with it, and also how we can utilize the V-Ray Denoiser standalone
tool in animation.
The rendering process is trying to calculate the right color of each individual pixel of
the image. The more time we allow for this process the more accurate the color of each
pixel would be. If we don't allow enough time though this would result in higher amount
of noise. The V-Ray Denoiser is a great feature that
could be used to lower the amount of noise in a rendered image, while preserving its details.
Furthermore, is the denoising process is much faster than the actual rendering and
this way saves substantial amount of time.
The denoiser works by taking into consideration several factors.
While working on the pixel of interest, it
looks around its neighboring pixels to determine if there is difference in the color.
Also, it looks into the "Normals" and "Point position" render elements to determine
if objects are overlapping and generally where in space they are located.
The denoiser generates a render element called "Noise level" which contains information
about how noisy certain area of the image is. This render element is a greyscale image
where the white areas have the most noise, black areas have no noise, and grey areas
have varying levels of noise. Using this information, the denoiser would know where to denoise more.
Another render element that's been created for the specific needs of the denoiser is
the "defocus" render element. This render element contains information about which parts
of the image are in focus and which are not. This way, the denoiser would blur more the
parts that are not in focus.
Using all of this information the V-Ray denoiser
manages to adaptively get rid of the noise and preserve all the details.
Before we get to the V-Ray denoiser in 3ds max,
let's render out our scene first. Let's lower the noise threshold significantly.
This way we could compare the result to the denoised image later in terms of quality
and render time. Using production quality noise threshold would take some time to render,
so let me fast forward the rendering process.
Once ready, let's save the image in the frame buffer history for later reference.
Under the render elements tab, we can add the VRay Denoiser.
Simply click on the add button and select the denoiser render element from the list.
Back in the V-Ray tab, let's increase the
noise threshold to 0.05 and render a region of the image. Let's choose a region that
has both focused and out of focus areas.
As mentioned earlier the VRay denoiser generates
several render elements needed for the denoising process. You can find them in the render elements
drop down list.
Let's take a look at the denoiser parameters.
Under the render elements tab, click on the VRayDenoiser and under the parameters rollout
you can select a different denoising preset.
In case we need very little denoising we can
select the mild preset and click update.
Or we can choose the strong preset or the default preset.
We can also select custom and specify parameters
for the strength and the radius. Once we've selected a denoiser preset it's
a good idea to compare with the original rendering if we've lost essential details in the denoising
process and if that is the case we should re-adjust the denoiser parameters.
We can repeat this process as many times as needed, for as many regions of the image as
we consider necessary. Once we're ready, let's render the whole image and compare
the render time to the production quality image we've rendered in the beginning of this presentation.
Let's save it to the history, and as you see there is a significant
speed improvement for close to identical results.
So far, we've covered a denoiser workflow
using the bucket image sampler. Let's take a look at a case using the progressive image sampler.
Let's switch the type to progressive, clear the VFB and start rendering.
At a certain time interval, the denoiser would
recalculate while the rendering is still on going. This way, each time the denoiser recalculates,
the image would get better. When the image quality reaches our level of satisfaction,
we can simply stop the rendering.
We can switch back and forth to the noised and denoised image to clearly see the difference.
Taking advantage of the denoiser feature can save us a great deal of time.
Time that we can use to make our images greater instead of waiting.
For a single frame that kind of waiting might not be a big deal
but when it comes to rendering animation, extra render time adds up.
In the case when rendering animation, the
V-Ray denoiser can analyze consecutive frames in order to provide a temporally stable result.
This can be done by using the denoiser standalone tool that comes with the V-Ray installation.
It takes a sequence of rendered images as an input. To get maximum effect it is strongly
recommended to include the render elements needed for denoising in the input files. If
you know that you are going to denoise the animation after rendering the whole sequence,
it would be a good idea to disable the denoising of each frame during rendering, but include
the REs needed for the denoising. Once fed to the denoiser, the tool would reduce
noise frame by frame until the end of the animation. On top of that, the denoiser tool
compares blocks of pixels from frames prior to the current one, and frames after the current
one. Using this information, it further refines the denoising process and produces smooth
transition between frames. This method not only reduces noise but also helps stabilize
shimmering in animation in areas with hair, fur and small details.
Set the denoiser to "Only generate render elements"
and render your sequence. Make sure you use the EXR or VRIMG file formats
when you export animation, since those formats can hold all the REs in together.
The V-Ray denoiser standalone tool comes with
the V-Ray installation and you can find it in the tools folder, denoiser tool.
When you open it, you need to type in the command for denoising which you can find if
you scroll all the way up.
Under usage we have the command we are looking for.
We need to provide an input file and also we can set some options. All of the options are listed here.
Let's copy the command,
scroll down and paste it.
We need to provide the required input images as a sequence.
Find your rendered images and simply drag and drop the first file of the sequence into
the command prompt window.
To set it as a sequence we need to replace the digits in the name with question marks.
Once ready to execute just press the enter button.
In this video, we went over the V-Ray denoiser tool.
The concept behind the denoising process, the denoiser settings and presets, and also
the use of the denoiser in animation. I hope you have found this video useful and
helpful. Please give us your feedback, comment, or share it. If you'd like to follow along
this tutorial, please download the scene from the video provided in the video's description.
Make sure you check out more of the V-Ray feature video and be on the lookout for new
ones. Thank you for watching.