| Q&A |
Stephan Hrbek,
LightSprint
Oct. - 2006
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"Lightsprint
is here to push global illumination from movies to realtime
software like games and architectural modellers. Being
fascinated by the way how light interacts with the environment
around us, we simulate it on CPU and GPU in realtime.
Our goal is not to compete with existing 3D engines,
on contrary, we integrate with them and improve them."
<
Realtime 3D rendering with LightSprint |
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| Q1 |
Please
give a brief presentation of Lightsprint. |
| A1 |
Lightsprint
was formed to help others add photorealistic illumination
to realtime 3D engines. Only a few years ago, global illumination
started to appear in CG movies like Shrek 2; Lightsprint is
here to push it from movies to realtime software like games
and architectural modellers. Being fascinated by the way how
light interacts with the environment around us, we simulate
it on CPU and GPU in realtime. Our goal is not to compete
with existing 3D engines, on contrary, we integrate with them
and improve them.
Although our technology is licensed commercially, our roots
lie in demoscene and free software, and we support free software
developers, saying no to software patents. We are based in
Prague, the Czech Republic. |
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| Q2 |
Lightsprint
Vision offers radiosity for realtime 3D engines, is it a real
radiosity? |
| A2 |
Yes,
technically speaking, it is a progressive radiosity with Monte
Carlo photontracing, clustering, adaptive subdivision, and
other optimisations. Unlike traditional radiosity with soft
shadows and color bleeding, it also supports specular surfaces
and refraction. |
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| Q3 |
What
kind of graphic cards can display soft shadows in realtime? |
| A3 |
Our
demo with true soft shadows from the area light and indirect
illumination runs on NVIDIA GeForce 6100 and any higher version
and ATI Radeon 9500 and any higher version. People on forums
often express their surprise that it runs even on their old
computers. |
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| Q4 |
What kind of 3D engine can use your illumination middleware?
Can 3D engines based on Java (JOGL, JMonkey...) use Lightsprint
Vision? |
| A4 |
Basically
any C++ 3D engine. Lightsprint libraries were designed to be
easily integrated with C++ rendering engines. They can serve
as a tool that rapidly precalculates indirect illumination or
as a rendering subsystem that calculates indirect illumination
in realtime. Soft shadows are optional and can be replaced by
client's native shadows. Advanced aspects of C++ language were
used and so any binding to Java would be difficult. |
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| Q5 |
With
Lightsprint Vision, is it the end of texture backing, shadow
map(...)? Does it inspire new workflow in realtime 3D creation? |
| A5 |
 Realtime
calculated indirect illumination significantly simplifies
the pipeline, it's no longer needed to add fake lights, run
an expensive lightmapper after each change in the scene and
it even looks good and realistically responds to all scene
changes. However, there will always be applications where
illumination doesn't change, so completely precomputed or
otherwise simplified solutions will stay with us.
For such cases, Lightsprint can be used for rapid lightmap
or ambient map creation. Regarding shadow maps, it's possible
to replace them by our soft shadows. Of course, it could be
complicated for some engines, so we don't rely on soft shadows,
we can integrate with shadows already present in 3D engine. |
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| Q6 |
Is
Lightsprint Vision optimized enough to be implanted in game
3D engines? |
| A6 |
Sure.
It's been under development for 7 years and all changes are
benchmarked, we are crazy about performance.
Our core collision subsystem was compared with widely used physical
engines by one of our clients who came to a conclusion that
we were up to 200 times faster and we needed 10 times less memory. |
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| Q7 |
Is
it possible to use FSAA with Lightsprint Vision to have the
"precalculated quality"? |
| A7 |
Yes,
FSAA improves the quality of our soft shadows, However, indirect
illumination stays unchanged. |
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| Q8 |
What
is the licence of Lightsprint? |
| A8 |
The
licence is simple, royalty-free and limited for use in one software
title, the client can integrate Lightsprint into a game, game
tool or into any other product. We like smaller projects with
limited funds too, so we can individually settle on a royalty
as a replacement for a fixed price. |
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| Q9 |
What
is the future of Lightsprint Vision in term of image quality?
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| A9 |
We
use the full power of CPU and GPU during the calculation, so
in the short run, image quality will leap forward with quad
core CPUs and DX10 GPUs.
In the long run, we would like to raytrace selected parts of
a scene and then have some fun by advancing nice fake
or foto quiz to "fake or video" quiz
where visitors guess what is the realtime computed animation
and what is the video. |
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