Gravel
www.rclsoftware.org.uk
Gravel is a simple simulation which models the behaviour of astronomical objects in space, according to Newton's Laws of Gravity.
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About Gravel
"Gravel" is short for "Gravity / Velocity Simulator".
How to use Gravel
You define several objects (stating their mass (kg), position (m) and velocity (m/s)) and Gravel calculates how these objects would behave in space.
You can even tell Gravel to place one or more objects in orbit around an other object and Gravel will automatically choose the right orbital speed.
How Gravel works
The basic principles are quite simple: For each object, Gravel calculates the acceleration caused by the mass & distance of the other objects, and adds that acceleration to the object's speed. The object's speed is then added to it's current position. This is done several thousand times a second.
History
Gravel started off as a programming experiment.
- Version 1 was written in C on the Amiga around 1996 using the Lattice compiler.
- Version 2 was written in C++ on Microsoft Windows in 2001 using the Borland Builder 4 compiler with the Windows Platform SDK.
- Version 2 is now maintained in C++ on Microsoft Windows using the Microsoft Visual C++ Express compiler with the Windows Platform SDK.
- Version 3 is being developed in C++ on Microsoft Windows using the Microsoft Visual C++ Express compiler with the Windows Platform SDK.
Comments and suggestions are always welcome,
and can be submitted via the feedback page.
Calculates the initial velocity needed for a satellite to follow a specific elliptical orbit.
NEWS:
27-FEB-08
A new Gravel v3 Preview with improved user interface is now available for download.
04-NOV-07
A new Gravel v3 Preview with improved support for Direct3D is now available for download.
30-OCT-07
The Gravel v3 SDK has been updated.
28-APR-07
The Gravel v3 SDK has been updated to Version 1.1.3 and is now implemented entirely in C.
30-MAR-07
The first Gravel v3 Preview version with support for Direct3D is now available for download.
26-FEB-07
The BETA test build of the next Gravel v3 Preview version is available.
28-JAN-07
Gravel v3 SDK will include support for .net and Mono.
In addition to the existing native implementation of the Gravel physics engine, the SDK will soon include pure verifiable assemblies written entirely in C#. It will therefore be possible to use the Gravel v3 physics engine in managed applications running on .net and Mono. Initial testing has shown execution speed to be satisfactory.
The DEC2006 version of Gravel v3 Preview is now available from the Gravel download page.
Gravel v2.0.2 is now available as a single install from the Gravel download page.
25-NOV-06
Gravel v3 Preview
The NOV2006 version of Gravel v3 Preview is now available from the Gravel download page.
This is the first of several 'sneak previews' showing some of the features of Gravel v3 - which include:
- Accurate control of simulation speed, eg. 1 'simulated' day per 'real' second.
- Optionally running in the background, only using spare processor capacity.
- Scripted artificial acceleration of objects.
- 2D and 3D viewing of Gravel simulations.
- Camera tracking of objects in 3D view.
- Textured planet surfaces in 3D view.
- Multiple light sources in 2D and 3D view.
25-SEP-06
Gravel v2 update
Gravel Update 2.0.2 is now available from the Gravel download page.
Features include:
- Control over the speed of the simulation.
- Logging the location and velocity of objects.
- Improved performance.
Note: Gravel v2.0.1 must already be installed before running this update.
11-SEP-06
Gravel v3 Preview is in the final stages of testing and a new BETA test version is available for download.
04-SEP-06
A new update of Gravel v2 is in the last stages of testing.
08-JUN-06
The Gravel v3 SDK has been updated to Version 1.1.2, with the following new features:
- Three different time frames are supported: seconds, minutes, and hours.
- The updated demo/tutorial is written in ANSI C and includes the VC2005 project files.
3-MAY-06
Gravel now has its own RSS feed!
28-APR-06
Gravel v3 Preview is being BETA tested!
31-MAR-06
The Gravel v3 SDK has been updated and is now in BETA testing.
31-DEC-05
Version 1.1.1 of the Gravel v3 SDK has been released.
The following improvements have been made:
- Three new API functions have been added, which make it possible to attach generic data to a Gravel scene, retrieve such data from a Gravel scene, and reset a Gravel scene.
- The documentation has been improved and the tutorial has been extended.
- A bug in the API function calculateLocalGravelAcceleration has been fixed.
- The API function advanceGravelTime can now be called specifying 0 seconds.
- The new source code has increased cross compiler compatibility.
20-DEC-05
The Gravel v3 SDK has been updated and is currently in BETA testing.
23-SEP-05
The Gravel v3 SDK has now been released!
16-MAY-05
The all new Gravel v3 SDK is now in beta testing.
20-JAN-05
There is now a JavaScript application on the Gravel website which calculates the initial velocity needed for a satellite to follow a specific elliptical orbit:
Calculating the Initial Orbital Speed of a Satellite
8-JAN-05
Work on Gravel v3 is generally on hold due to ongoing work related to the Dendros File Format which Gravel v3 will use.
15-JUN-04
The new Gravel v3 Demo has now been published.
The new version shows Jupiter with its inner moons.
- Gravel v3 is now being developed using the recently released Microsoft Visual C++ Toolkit 2003 with Microsoft's Win32 Platform SDK Feb2003.
- Due to the decline in Windows 98 usage, only Windows 2000 and Windows XP will be supported in future Gravel releases (except the SDK). This will make it possible to use the full power and features of the newer operating systems, including full unicode support.
- The Gravel v3 Physics Engine is being expanded and redesigned. Therefore the existing SDK Beta Download is no longer meaningful and has been removed from the download section.
- A brand new Gravel v3 Demo featuring Jupiter and it's inner moons is planned for release in mid-June.
3-APR-04
The
Gravel v3 Demo has been updated.
The new version, which uses the latest Gravel v3 SDK code, shows a small satellite in close orbit around the earth.
30-MAR-04
A new beta test version of the Gravel v3 SDK has been released.
28-FEB-04
Gravel v2 has been updated !
Gravel v2.0.1 runs approximately twice as fast as Gravel 2.0.0.
The installer also includes the new Gravel v2 Editor and comes with updated Gravel v2 scenes.
Click here to download the new version.
31-JAN-04
A beta test version of Gravel v2 Editor has been released.
25-NOV-03
The first beta test release of the
Gravel v3 SDK is now available !
Also, the reference section of the SDK documentation is now online.
11-NOV-03
The newest
Gravel v3 Demo is now available !
The latest version runs far quicker then the first Demo, thanks to optimisations in the Gravel v3 SDK.
Also, it is now possible to switch between full screen view and a window view.
27-AUG-03
Screenshots of the Gravel v3 Demo have been published on the Gravel v3 page.
22-JUL-03
The draft of the C++ header file describing the Gravel Physics DLL's API has been published.
10-JUL-03
The first Gravel v3 Demo is now available for download.
23-NOV-02
The next version of Gravel is now in production.
The release of the Gravel "Software Development Kit" (which will support 3D simulations) is also planed.
This will be in the form of a DLL with a standard function call interface.
Feedback and suggestions are most welcome!
