These are tensile-only members - capable of resisting extension, but not compression
Nodes:
Joints, hubs and connectors
Skins:
These are membranes, capable of joining the gaps between struts
The simulation is performed in a virtual world with either
two or three spatial dimensions.
Forces simulated in Springie's universe include
compressive and tensile forces, electrostatic attraction and
repulsion, elastic collisions, gravity and friction.
Models of physical objects can be dynamically edited and
manipulated in this environment.
Persistence of Springie's models is performed using XML.
Model import
Springie allows import of models in a number of
formats. It reads:
.SPR files:
An XML-based file format - Springie's native format;
.EIG files:
"Elastic Interval Geometry" files - associated with SpringDance;
.RBF files:
"Richard Buckminster Fuller" files - associated with Struck;
.OFF files:
"Object File Format" files - as produced by Packinon and GeomView;
.M files:
"Mathematica" files - associated with Mathematica and LiveGraphics3D details here;
.DAT files:
"TView" files - by Bob Burkhardt - models are available [here] or [here];
.FABRIC files:
.FABRIC files are associated with Fluidiom;
Support for importing other formats is planned.
Model export
Springie can also export models a range of formats:
.SPR files:
.SPR files are an XML-based file format which is native to Springie.
.POV files:
.POV files are readable by the popular ray-tracing package, POV-Ray -
which can be used to generate high-quality still images of the models.
.WRL files:
.WRL files (i.e. VRML model files) allows for higher quality
rendering than Springie offers natively - while still
allowing easy access to the models in an interactive 3D space
to users via a web browser.
.EIG files:
.EIG (Elastic Interval Geometry) files are readable by the
program SpringDance - and some versions of Struck.
.OFF files:
.OFF (Object File Format) files are readable by the programs in the
packinon project - and a number of other 3D model readers.
Support for exporting in other formats is planned.
Note that you will need to run Springie as an application
(rather than an applet) if you want to be able to read or
write files.
This limitation is due to security restrictions placed on
what unsigned applets can do.
Rendering options
To provide an illustration of the available rendering approaches,
here are some snapshots of Springie output:
Springie rendering
VRML rendering
POV-Ray rendering
Embedding models in web pages
There's a low-bandwidth version of Springie - known as SprView.
This runs as an applet and loads compressed model files from
archives over the internet.
SprView is intended for embedding tensegrity models in web
pages.
