Tutorial

Creation of your project

This tutorial explains essentially how to obtain the basic files that are necessary to represent a scene in LASER/F and to perform a simulation.

1) What does a LASER/F project need?

2) The configuration file

3) The 'xxx.geo' file which contains the geometry

4) The 4 material files

5) Import your new project into LASER/F

6) Create your meteo forcing file

1) What does a LASER/F project need?

A LASER/F project corresponds to a simulation scene, i.e. a particular geometry on which you want to perform simulations. Each project must have a short name for example: brooklin, argonne, abbypark... By commodity, this name is replaced by 'xxx' below. It is strongly recommended to create a specific directory for each project to store its files. Each project is made up of a minimum of 6 basic files:

1) xxx.csl
2) xxx.geo
3) xxx_materiel.mat
4) xxx_revetement.mat
5) xxx_revetement.lai
6) xxx_materiau.mat

The sections below describe how to obtain (or create) these files.

2) The configuration file

The 'xxx.csl' file contains some rudimental information that will be displayed in the interface of LASER/F when you will import your project the first time. There are two methods to create this file:

1) Open a text editor and copy the content given as example below > save the file in your project directory as 'xxx.csl'
2) Copy the file '*.csl' that is stored in the demonstration directory in the directory of your project and rename it as 'xxx.csl'

There is no need to modify the content of this file.

The 9 lines below are an example of the content of a 'xxx.csl' file :

5; Superficie Min. pour la fragmentation10; Superficie Max. pour la fragmentation0.5;Seuil pour la fragmentation ------>remove this line with old versions below 2.1.0 0; Flag pour la fragmentation progressive3; Nb divisions du ciel0; Coordonnee de reference (X) pour la fragmentation progressive0; Coordonnee de reference (Y) pour la fragmentation progressive0; Coordonnee de reference (Z) pour la fragmentation progressive1; Flag pour savoir si les objets sont fragmentés

3) The 'xxx.geo' file which contains the geometry

LASER/F has been designed to account for geometry with a high level of detail (LOD 3 if necessary). The urban geometry that corresponds to your simulation zone must be provided in a 'xxx.geo' file according to a specific convention. This file can be edited by the user in any word processing software (example beside). The GEO file format convention is explained in a notice that can be downloaded here. The construction of this file is a very delicate part of the project. It requires a special attention and a lot of time, especially if the area to be simulated is large. There is no automatic method to obtain it, in all cases manual intervention is necessary: 'construction.geo' file located in the 'Demo' directory can serve as an example.

A specific software, called CSL (Constructeur de Scène Laser), is under development to facilitate the construction of this file (in preparation).

xxx.geo
File containing the 3D geometry of the simulation domain

4) The 4 material files

The user must specify the characteristics of all the materials used in his simulation scene. This is done in 4 text files that will form the specific material database of the project.

1) The 'xxx_materiel.mat' file is the master material file. It makes the links between the "xxx.geo" file (see below) and the three other material files. This file defines also the number and depth of the layers
2) The 'xxx_revetement.mat' file identifies the coatings of the materials (emissivity, reflectivity...)
3) The 'xxx_revetement.lai' file gives the decadal values of Leaf Area Index (LAI) of materials with vegetation
4) The 'xxx_materiau.mat' file identifies the thermophysical properties of the layers (density, heat conductivity...)

Default material files are provided with the demonstration project. The user can adapt them to its needs by adding or deleting materials. An explanatory note of the content of these files will soon be available.

xxx_materiel.mat
Master file

xxx_revetement.mat

Coating file

xxx_revetement.lai
LAI file

xxx_materiau.mat
Thermophysical file

5) Import your new project into LASER/F

Once you have correctly built the 6 files you will be able to import your project in LASER/F according to the procedure described below. You can apply the steps that are described, with the files provided in the demo project.

Launch LASER/F,
Menu bar > 'Projet' > 'Importer CSL'. In the opendialog box choose the correct directory and your 'xxx.csl' file > 'Open',
If all is as expected, your project is imported without error messages, otherwise there is something is wrong in your files. It is also possible that a warning message 'Un étage du bâtiment N°x n'a pas de mur' could appear, simply ignore it > 'OK',
Check that the materials have been imported correctly > 'Materiaux' page. It is not possible to modify the materials here: this page is only used to view the content of the material files related to the project,
Go to the 'Géométrie' page > 'Fragmentation' groupbox, click on the white label entitled 'Superficie. min' and type the resolution of the fragmentation you want to achieve (in m²), e.g. '20'. Be sure the checkbox entitled 'Fragmentation progressive' is unchecked. click on the 'Fragmentation' button. LASER/F starts an automatic procedure to detect the visible meshes: depending of the size of your scene and the power of your PC this procedure can take a lot of time (up to a day for very big and complex scenes). It creates a 'xxx.vi' file in the directory of your project.
With version 2.1.0 it is now possible to modify the size of the atmospheric boxes of the urban canopy layer in the 'Géométrie' page.
When step 5 is finished, activate the 'Visualisation' form > check 'Fil de fer' and visualize the results,
Register your project: activate the 'Main' form > menu bar > 'Projet' > 'Enregistrer'.

The fragmented geometry of your project is now registered in a 'xxx.fra' file. A file called 'xxx.lsr has also been created: this file contains all the options related to your project.

'Fragmentation' page

Detection of visible meshes

Fragmentation: creation of triangular meshes

6) Create your meteo forcing file

This file contains the meteorological information necessary to conduct a simulation. It is recommended to give it the .csv extension. Please refer to the technical note that describes in detail how to build this file (download it from ResearchGate here).

Well... your project is now ready for a simulation (see the next tutorial).