| Q&A |
 Delta
3D
Perry McDowel
oct. 2006
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"Delta
3D is
supported by a core of professional developers whose
job is to produce applications on the engine. In doing
so, they ensure that the engine is stable, new updates
are released periodically, and new functionality is
added to the engine, and finally, it won’t go
away like many open source projects seem to do."
<
Delta 3D Cave simulation |
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| Q1 |
Please
give a brief description of Delta3D. |
| A1 |
Delta3D
is an open source game (LGPL license) and simulation engine
designed specifically to build “serious games,”
i.e., games which are designed to deliver more than just entertainment.
While serious games include games to convey a message, such
as political or advertising games, the area we are most involved
in is games for education and training. Delta3D is not intended
to compete with the major commercial engines; rather, it is
intended to offer a robust and easy to use alternative with
can offer all the functionality that be classified as “commodity.”
What we mean by that is that Delta3D is not meant to be on
the “bleeding edge” of technology, but rather
provides what is commonly available outside of the best engines.
Delta3D has been constructed in a modular fashion, using other
open source libraries to provide the major modules. For example,
our rendering is provided by OpenSceneGraph, our physics by
Open Dynamics Engine, our audio by OpenAL, etc. This gives
us the benefit of having all the developers in all those projects
working to improve Delta3D, whether they have heard of it
or not. It is an easy way to keep our engine current. Additionally,
if one of these projects is surpassed by another as the best
of breed, we can replace it in the engine.
Delta3D is designed to be multi-genre, making it easy to hook
together games of different type, such as a first person shooter
where the player is getting orders from another player in
a real time strategy environment.
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| Q2 |
A
lot of 3D engines exist in both commercial and opensource domain.
What make Delta3D different? |
| A2 |
Delta3D
is different in many ways from most of the other open source
engines available. Firstly, it is supported by a core of professional
developers whose job is to produce applications on the engine.
In doing so, they ensure that the engine is stable, new updates
are released periodically, and new functionality is added to
the engine, and finally, it won’t go away like many open
source projects seem to do.
Secondly, the modular construction mentioned above allows the
engine to improve as the other projects which make up Delta3D
improve.
Thirdly, because it is licensed under the Lesser Gnu Public
License (LGPL), it is possible to combine proprietary code with
Delta3D without making that code open source, and applications
built atop it are not required to be open source. The LGPL does
not have the viral nature of the GPL.
Lastly, if you are building serious games, it has the capability
to communicate with a SCORM compliant Learning Management System
(LMS). This means that it is much easier to track the progress
of students through a curriculum of game based learning if the
games are built using Delta3D. |
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| Q3 |
Delta3D
work closely with Open Scene Graph, does it means that Delta3D
can display large geographic data? |
| A3 |
Yes.
Delta3D has been used for several flight simulators, in a wide
variety of media: CAVES, desktops, chromakey systems, etc. It
can directly import DTED data using a continuous level of detail
algorithm to produce geo-specific terrain, or it can produce
an infinite terrain that can be modified by the programmer. |
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| Q4 |
Is
it possible to import and manage character animation (bones,
skining) from 3ds max, Maya or Softimage XSI? |
| A4 |
Delta3D
uses the CAL3D open source project for character animations
and relies on the existing CAL3D exporters – currently
Max and Blender3D. CAL3D allows artists to create a skeleton,
associate an animation with the skeleton, and map the skeleton
to a mesh. All three pieces get loaded into Delta3D which render
the character and allow for animation control.
Non-skeletal keyframe animations can also be exported out of
Max using an Open Scene Graph exporter plugin. The functionality
lets the artist export cyclic animations such as rotating doors
and propellers which can be controlled through the engine. |
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| Q5 |
What
is the level of Delta 3D in term of 3D performances (fps) and
3d effects (per pixel or vertex shaders)? |
| A5 |
Delta3D’s
main development criterion is to provide a stable, high-level,
full-featured game engine that is easy to use for beginners.
While Delta3D might not operate at the same performance as a
top-of-the-line commercial engine, the ease of use and hardware
compatibility makes up for it.
Delta3D can support both per pixel and per vertex shading and
still have great performance utilizing the latest in graphics
hardware. |
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| Q6 |
Is
it possible to create a complete flight simulator using Delta3D? |
| A6 |
We
have created one already in our lab: it is a three wall CAVE,
with inputs from a stick, throttle, and rudder pedals. Information
such as altitude, flight attitude, and location are sent to
a gauge board and GPS box for output to the user. This application
has already been used for a wide range of applications in our
lab for the FAA, and the results have affected the rules for
aircraft separation in the US.
This application demonstrates one of the advantages of our licensing
under the LGPL – rather than go to the trouble of developing
an advanced flight model, we bought a copy of X-Plane, $49 software.
The user’s inputs from flight controls are read by X-Plane.
X-Plane then determines what the aircraft result should be and
passes the data to Delta3D. Delta3D then displays this visually
on the screens and gauges. |
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| Q7 |
Do
you plan to support Collada format? |
| A7 |
We
have no plans at this time to add support for Collada ourselves.
However, since we are open source, if any of our users would
like to create support for Collada in Delta3D, we would gladly
add it to the engine or as a node kit. |
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| Q8 |
What
are the feature of Delta3D concerning network/internet? |
| A8 |
Delta3D
has three main type of networking options. It has the normal
client/server networking found in games. Additionally, it has
the capability to support both HLA and DIS, so it can easily
support military applications. |
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| Q9 |
Is
developing a game or a 3D application with Delta3D easy for
C++ developers (complete documentation, reactive community)? |
| A9 |
Yes,
we have gone to a great deal of effort to make it as easy as
possible for someone with programming experience to start using
and get applications built quickly. From the beginning we have
expected this to be used by industry, and we know that it will
not accept poorly the documented and difficult to understand
code many open source projects have. Our documentation page
(link)
has the engine’s entire documentation.
Besides an in-depth description of the API that programmers
would expect, this page has discussions and instructions for
all aspects of the engine. It explains our design philosophy
and many of our design decisions. Also, from this page application
builders can find links to our over forty tutorials, which walk
programmers through all steps, from setting up their environment
for both Windows and Linux, to building a “Hello World”
app, to more advanced functionality.
In addition to all this, the download of Delta3D comes with
examples for almost all of the engine’s functionality,
so it is easy for programmers to see how to implement all of
Delta3D’s functions.
However, if all that fails and users have questions, they can
go to our forums (link).
There, both our staff and developers unassociated with our team
will answer the question in a relatively short time. Most questions
are addressed within 24 hours.
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