Tutorial

Main steps of a simulation


This tutorial explains how to perform a simulation.

1) What's necessary?


You need 7 files at this stage:

1) xxx.lsr
2) xxx.fra
3) xxx_materiel.mat
4) xxx_revetement.mat
5) xxx_revetement.lai
6) xxx_materiau.mat
7) *.csv

If you work with your own project, you must have complete entirely the steps of the preceding tutorial before to be able to perform a simulation. The first 2 files have been generated by LASER/F when you requested a fragmentation and when you registered your project (see points 5.5 and 5.7 of the tutorial). Files 3 to 6 are the specific material files you created for your project (point 4 of the tutorial). File 7 contains the meteorological information necessary to force the simulation (point 6 of the tutorial).

If you work with the demo project these files are provided in the directory.

2) Open the project


Open the project:

  1. In the menu bar of the 'Main' form > 'Projet' > 'Ouvrir' > choose the 'xxx.lsr' file

  2. If the 'xxx.vi' file doesn't exists in the project, it is recreated: normally it was created when you import the project (see previous tutorial). This procedure can take a lot of time (up to a day for very big and complex scenes).

3) Define the final resolution of your simulation


If the resolution you chose when you did your first fragmentation doesn't suit you, then you can start the procedure again:

  1. In the menu bar, 'Géométrie' > 'Fragmentation' > 'Réinitialiser'.

  2. A warning message could appear 'Un étage du bâtiment N°x n'a pas de mur', simply ignore it > 'OK',

  3. Activate the 'Géométrie' page > 'Fragmentation' groupbox >, click on the white label entitled 'Superficie. min' and modify the value of the fragmentation (in m²) > 'Fragmentation' button.

  4. When step 3 is finished, activate the 'Visualisation' form > check 'Fil de fer' and visualize the results,

  5. If you are not satisfied you can repeat the procedure from step 1,

  6. Register your project: 'Main' form > menu bar > 'Projet' > 'Enregistrer'.

'Fragmentation' page

Detection of visible meshes

Fragmentation: creation of triangular meshes

4) Define the options of your simulation


Before to launch your simulation, some options must be specified. This is done in the 'Simulation' page. The meaning of these options is given in the following paragraphs.


Groupbox 'Période de simulation': time management.

  • 'Heure de début': the date and time for the start of your simulation (UTC)

  • 'Heure de fin': type date and time for the end of your simulation (UTC)

  • 'Pas de temps': the timestep of the simulation (in seconds) (must be lower or equal than the timestep of the meteo forcing file

  • 'Fuseau': time zone (not tested for the moment)

  • 'Décalage': period (in seconds) to be added or subtracted to synchronize the simulation with the weather forcing data if they represent averages


Groupbox 'Fichiers': files management.

  • 'Nom du fichier de forçage': name of the meteo forcing file covering the simulation period,

  • 'Cinétique': check it if you want to simulate all timesteps between 'Heure de début' and 'Heure de fin'. If you let it unchecked only 'Heure de début' is simulated,

  • 'Sauvegarde': check it if you want to store the results in files (*.reb),

  • 'Intervalle de sauvegarde': desired timestep of the storage files (in seconds), if 'Sauvegarde' and 'Cinétique' are checked,

  • 'Texte générique du fichier de sauvegarde': generic text placed at the beginning of your backup files. These files are saved with the .reb extension,

  • 'Restart': a possibility is given to pursue a simulation after it ends. If this is checked you must indicate the *.reb file that will be used to initialize the simulation,

  • 'Nom du fichier de restart': name of the *.reb file that will be used to make the restart, if 'Restart' is checked.

The 'Simulation' page

Groupbox 'Rayonnement solaire': components of solar radiation you want to simulate,

  • 'Direct incident': to simulate the direct solar radiation,

  • 'Diffus atmosphérique': to simulate the solar diffuse radiation,

  • 'Anisotrope': to simulate a anisotropic sky during computation of diffuse solar radiation. If unchecked, simulation is faster and diffuse radiation is calculated with an isotropic sky,

  • 'Entre objets': to simulate solar exchanges between the ground elements,

  • 'Radiosité': solar exchanges between the ground elements can be simulated by using a radiosity algorithm (very time consuming). If unchecked, simulation is faster and solar exchanges are approximated

  • 'Réfléchi lambertien': solar reflected radiation.


Groupbox 'Rayonnement IR': components of infrared (IR) radiation you want to simulate,

  • 'IR atmosphérique': to simulate the atmosphérique IR radiation,

  • 'Emis': to simulate the IR radiation emitted by the ground,

  • 'T. surface': to simulate realistic surface and ground temperatures: if unchecked these temperatures are constant ,

  • 'Entre objets': to simulate IR exchanges between the ground elements,

  • 'Radiosité': IR exchanges between the ground elements can be simulated by using a radiosity algorithm (very time consuming). If unchecked, simulation is faster and IR exchanges are approximated.


Groupbox 'Radiosité progressive': radiosity management,

  • 'Energie non dissipée': energy (in W/m²) below which radiosity is stopped. Recommended value: 1,

  • 'Facteur distance': distance at which energy is dissipated. Depends of the geometry of your scene. Must be < 300m,

  • 'Nb. max itérations radiatives': number of iterations allowed to stabilize the surface temperature. Recommended value: 3

5) Launch the simulation


In the 'Simulation' page, click on the 'Simulation' button. Follow the progress of the task on the progress bar located at the bottom of the “Main” form. The 'Stop' button allows you to cancel the simulation (the stop is only effective after the end of all parallel processes). At any time you can interrupt a LASER/F simulation in the Windows task manager by killing the process.