| Q&A |
Mental Ray 3.8,
Ludwig
von Reiche, Chief Operating Officer for mental images
November - 2009
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“iray
introduces a new way of utilizing photorealistic rendering,
by integrating both preview and final frame rendering
in one single interactive process. In addition, the
power of the CUDA GPU dramatically shortens the processing
time, introducing significant cost optimizations along
the rendering pipeline. And the handling simplifications
of iray provide a tool that enables professionals to
focus on their core business, while still being able
to generate beautiful photorealistic images of their
works, all without the help of rendering experts and
without the need of becoming rendering experts.”
<
Those images show a natural lighting of mental images
offices at different time : end of the afternoon (top)
and night (bottom).
This scene is rendered with iray technology. Images
are rendered on every light changes and camera position.
The scene contain 3 millions of triangles and 500 MB
of data. |
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| Q1 |
mental
ray 3.8 introduces the new iray technology. Does this technology
come in supplement to rendering engines available in mental
ray or does it replace some illumination methods like final
gathering ? |
| A1 |
The
iray rendering technology comes in addition to the regular
rendering modes of mental ray. It is not a replacement for
any current mental ray feature. mental ray 3.8, with iray
included, will be publically available starting in late November
2009, and at no extra cost to existing customers. |
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| Q2 |
Will
computer graphics artists, having already configured a scene
with materials available in mental ray 3.7, be able to compute
it directly and benefit from the GPU acceleration of mental
ray 3.8 ? |
| A2 |
Yes,
artists who have created scenes in mental ray 3.7 can move
those scenes into mental ray 3.8 to take advantage of mental
ray 3.8’s additional features. The speed of iray is
consistent and fast, and is further enhanced by the increasing
number of GPUs used. However, iray does not use mental ray
shaders. Therefore, a translation is required. If the materials
used to create the original scene belong to mental images'
mia_material set, the transition will be almost effortless,
otherwise there will be tradeoffs and limitations. iray is
a physically correct renderer: as such, it only supports physically
correct materials and light sources. |
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| Q3 |
Is
there a 100% CPU version of iray ? Is it then possible to benchmark
mental ray to see the benefits brought by the GPU ? |
| A3 |
Yes,
there is a 100% CPU version of iray. Benchmarks are being
executed at the time of this interview, and they will be available
soon. |
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| Q4 |
Will
mental ray 3.8 support all the NVIDIA boards or only the professional
range with Quadro? To get good performance with iray, what is
your choice within the NVIDIA range ? |
| A4 |
iray
supports any CUDA 1.1 board. Depending on model complexity,
the optimal choice could be a Tesla® or Quadro®
system.
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| Q5 |
Do
you think that the fact that mental ray is only accelerated
by the NVIDIA boards will damage to its adoption ? |
| A5 |
On
the contrary, there is a strong demand for CUDA-based pipelines,
and even a stronger demand for software that can take full advantage
of this extraordinary new technology. With the advent of Fermi,
such demand will simply grow. |
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| Q6 |
Could
you describe to us how you see the different techniques of mental
ray rendering coexist ? Can iray cover all the uses ? |
| A6 |
mental
ray is a fully programmable solution: programmers can create
shaders that do anything, including cartoon rendering and any
sort of non-photorealistic feature. In fact, artists can combine
those shaders in any way to come up with any possible effect.
mental ray is a solution that focuses on delivering full flexibility
to the widest spectrum of users.
iray is focused on photorealistic rendering and provides a unique
new balance between quality, performance and ease of use. iray
shaders can only represent real life materials and lights. There
are no complex setups required in iray to define indirect illumination:
the end user simply has to press a button and iray will take
care of everything in the best possible way. iray is suitable
for those who need to focus on their core businesses, do not
have time to learn a new sophisticated technology to create
photorealistic renderings, and yet do need to produce photorealistic
renderings of their works. Also, iray focuses on a new concept
that integrates pre-final visualization and final frame rendering
in one, interactive stage. |
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| Q7 |
Final
Gathering is particularly performant for fixed images, but some
regret not being able to use it for animated scenes because
of flickering. Do iray lighting models have flickering
? |
| A7 |
iray
does not use approximative algorithms such as final gathering,
ambient occlusion and such. Simply put, iray simulates the physical
behavior of light, without compromises. iray results are truly
photo-real. |
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| Q8 |
To
what does a iray renderfarm look like? Is it possible to benefit
from several Tesla units? |
| A8 |
Yes.
We are currently working on benchmarks and plan to release these
in December 2009. |
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| Q9 |
Today,
mental images customers propose mental ray per node (CPU) licenses.
How will happen the split with iray ? |
| A9 |
Our
policy will not change much - we will just consider all GPUs
as nodes, in addition to CPUs. Our goal is to continue to make
our technologies as easy to use as possible for new and existing
customers. |
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| Q10 |
Today,
"Architectural" materials are supported by iray :
do you mean all the parameters (ambiant occlusion, reflection
gloss....) ? Do you plan to support a larger spectrum of materials
? |
| A10 |
 iray
supports all parameters that contribute to define a physically
correct material. Other parameters, obviously designed to provide
approximative and artificial effects, will be ignored. That
said, we are planning to support a wider spectrum of materials
with iray in the future to meet the many needs of the artist. |
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| Q11 |
Will
it be possible to export a scene lighted with mental ray 3.8
so that is exploited with RealityServer ? |
| A11 |
Since
iray is implemented in both mental ray 3.8 and RealityServer
3.0, a scene that is rendered within mental ray will render
just as fine in RealityServer. When using the regular mental
ray 3.8 renderer, the scene will be rendered by RealityServer
with or without approximations, depending on the shaders used.
If the shaders used are based on MetaSL, the scene will render
just fine. For all other cases, a translation will occur; such
translation might result in more or less visible differences. |
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| Q12 |
What
do you think about iray : is it really the revolution we expected
"mental ray on GPU" ? Will this change and enhance
the graphics industry ? |
| A12 |
 We
believe that iray has the potential to revolutionize rendering—certainly
for certain use cases. iray introduces a new way of utilizing
photorealistic rendering, by integrating both preview and final
frame rendering in one single interactive process. In addition,
the power of the CUDA GPU dramatically shortens the processing
time, introducing significant cost optimizations along the rendering
pipeline. And the handling simplifications of iray provide a
tool that enables professionals to focus on their core business,
while still being able to generate beautiful photorealistic
images of their works, all without the help of rendering experts
and without the need of becoming rendering experts. |
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