History and Background
EasyAnim is a free visualization tool initially developed by Olivier Verlinden (Olivier DOT Verlinden AT fpms DOT ac DOT be), Faculté Polytechnique de Mons, to serve as a lightweight visualization tool for the multibody symbolic analysis tool EasyDyn.
As one of the drawbacks of MBDyn has always been the lack of a graphical user interface, EasyAnim has been used for a while as a simple visualization tool. Recently, the need for more specific visualization capabilities, and the lack of continuing support from the original Authors of EasyAnim, suggested to take over the project at Politecnico di Milano.
So we branched out of EasyAnim's main project and, thanks to its GPL license, we are now continuing development on our own. We are doing this focusing on the needs of MBDyn, in the hope that our development may be of use also to other users of EasyAnim and of other multibody analysis software.
One caveat: EasyAnim is built on top of the V library, which was a very nice attempt to provide a platform-independent, easy-to-use support for graphical user interfaces. Unfortunately, that project seems to be lagging a bit behind; however, for EasyAnim's needs, its functionalities seem to be just fine, thus the overall architecture. This library aims at providing complete support for most Un*x-like and Windows platforms. Since Windows is not currently used by MBDyn developers, compatibility of our development with Windows is not guaranteed, as we do not have resources to take care of it. Users and developers that need to use EasyAnim with Windows are encouraged to check and complete the support for Windows and contribute it back to the project.
Use of EasyAnim
The original EasyAnim, as of version 1.3, allowed to load models (the .vol file), play simulation results referring to that model (the .van file) and play complex mode shapes either in native or in Universal File format.
The version from Politecnico di Milano added more flexibility in the model definition, while preserving full compatibility with existing .vol files.
Additional features include the possibility to generate images (.ppm), movies (.mpg) and to visualize analyses online, reading the motion information from a data stream (either LOCAL or INET sockets).
To format the output of an MBDyn analysis as required by EasyAnim, use the mbdyn2easyanim.sh script. It is installed in MBDyn's
After executing an analysis with MBDyn, run the script with the output file name without extension as the only argument. For example:
mbdyn -f inputfile -o outputfile mbdyn2easyanim.sh outputfile
The script usually expects to find the files .log and .mov, and generates a .vol file containing the description of the model and a .van file containing the positions of the nodes for the duration of the simulation. If the .mov file is not present, no .van file is generated.
The script can generate extra items according to default patterns that exploit the amount of information in the .log file. To alter this behavior one could hack the .log file (documented in the "Log File Format" chapter of the input manual; please read MBDyn's code for further clarifications), or add some simple
The figures below present few snapshots of a tiltrotor semi-span wind-tunnel model as resulting from the plain use of the mbdyn2easyanim.sh script.
This link points to a few movies obtained from MBDyn simulations by means of different tools, including the modified version of EasyAnim.
Future development will address:
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