About Let There Be LIGHT

What's LTB-LIGHT
Let There Be-LIGHT is a Mac OSX application specialized to perform lighting calculations, such as monitoring the amount of energy, fixtures layout by type, quantity and power, control and verification of compliance with the law of the plants, etc..

LTB-LIGHT works in CAD unit metric or imperial platform, runs on Apple computers running OSX 10.8 Mountain Lion (minimum 10.5 Leopard), fully respecting the specific technology and implemants OpenGL for rendering. The demo version has full funcionality, but marks the results with an 'x': once LTB LIGHT is registered, all documents, even those built with the demo version will be unlocked for a full reading of the results.

The simplicity of use and the interface modeler should not be fooled; LTB LIGHT is not a classic CAD, but has similar tools in order to obtain a simple and effective input. CAD tools are used to create the scene to perform subsequent calculations. Applying the "sources", the set will be complete. We must start calculations and wait for the results. Then continue to verifications, both visually (on the virtual space generated by the program) and technically (through the amount of developed data).

Calculations proceed on any surface both flat or not (eg biconvex surfaces such as spheres and ellipsoids), architectural objects, streets, monuments, galleries, exhibition halls, and any other setting, geometrically complex, difficult to outline and calculate through the use of the usual tables and/or diagrams.

LTB-LIGHT, has an implementeable internal database containing:
  • geographic/territorial information of the main italian cities;
  • lighting sources catalogues and linked multi-currency prices files;
  • electrical wires catalogue and linked multi-currency prices files;
  • special pieces catalogue and linked multi-currency prices files;
The program has CAD interface that can generate morphologically defined parametric objects (vaults, hipped, domes, etc..) Or freely be generated through the use of primitives (cubes, spheres, cones, etc..)in order to simplify the design procedures: units are metric or imperial.

The working window projects objects within a three-dimensional space that displays the axial reference system and a plane of virtual modeling. The rationalization and intuitiveness of the available commands allow the acquisition of the graphics tools provided by the program, minimizing the learning curve. Moreover, UNDO and REDO command, and automatic recording of files on disk in case of system crash or power failure allow the possibility of control and security in the work developing.

Powerful LAYER management, intelligent PASTING options (the program allows to copy the attributes of an object and paste only those that is possible to transfer on an object with different characteristics), rectangular and polar ARRAY, EXTRUSION, online HELP for the execution of commands: these are some of the possibilities offered by the program.

The light sources, calculated as volumetric sources, are managed entirely by the program, which allows you to import, display, edit and format IESNA LM-63 (ASCII text files normally used by manufacturers of lighting fixtures-North Americans), EULUMDAT (formed by European standards) and even drawings DXF (the program converts drawings photometry!) data files; photometric solids are summarized in 36 azimithal C-curves and 180 zenithal gamma-angles, while the color of the lamps is given by the color temperature or real RGB color.

The program can export to RTF a complete list, formatted according to user needs, of the installed products and special items, full of economic computing and installed electrical power.

LTB-LIGHT provides users with powerful tools for design optimization: a window of pre-project for rectangular rooms, L or cutted-corner, with the CIE method, the correct number of sources to achieve a certain value of illuminance on the working surface.

There is also a utility for the road projects optimization calculated following last Regulamentations (UNI 11248/2012): given the width of the seat, through the choice of a variety of sources, distance and height of the poles, brackets, inclination, ..., LTB-LIGHT builds a database for each configuration with all the performed simulations. Through the use of filters you can choose from all the simulations carried out those that meet the parameters of law, the minimum installed capacity per kilometer, the configuration with maximum average luminance, ....


The Method
After creating or DXF-importing the scene,the method used for calculations, is the radiance one.

The objects of the scene to calculate, are divided into finite elements which assess the amount of direct illumination due to natural sources (sun and sky) and/or artificial. The method involves the calculation of multiple reflections (for the interior) until the complete redistribution of the illuminance (unless the user do not stop the calculation). In the event that the calculation has been interrupted, the user can resume from where it was suspended to take it to completion.

The information available when calculation is done are both visual (screen image) and numerical for the required verifications. The final real view is built in real colors or in 8-colors scale.


Video output
The individual surfaces of the object subjected to calculation are editable and can be projected on a plane and presented with the actual colors on both faces. Furthermore, the entire scene appears on the screen and and can be modified in real time, because the program keeps all lighting information previously calculated.

This means that the calculation time is long, but still proportional to the complexity of the scene and the number of the arranged light sources but, by counterpart, once completed, allow a total control of the scene, in real time and from whatever point of view we choose.

LTB-LIGHT has also a tool section which shifts the normal plane of the lens (the plane of the screen) forward or backward from the observer cutting, always in real time, the scene to verify the illuminament of interior spaces that are not visible.


Numerical output
The outputs of numerical type can be plotted on the surfaces projected on the plane and shown in isovalue curves:
  • Illuminaments horizzontal, vertical X+, Y+, X-, Y-, semi-cylindric and in main-camera direction;
  • Luminances;
  • Daylight coefficient;
  • RGB;
  • Contrast factor (C.R.F.);
  • Glare indexes (TI, G, U.G.R., C.G.I. and G.R.);
  • lighting pollution.
The displayed curves can be represented in color overlaying the view, print directly, pasted to the clipboard or saved in one of the allowed export formats (DXF, PDF, PICT vector, ...).


What's the use
It is clear that, after this introduction, the use of LTB-LIGHT is wide but targeted on well defined problems. LTB-LIGHT is a flexible, fast and simple tool to address and solve problems related to various professional activities as well as to different purposes of practical application.

It is also a powerful and intuitive verification tool to assess the compliance of systems to specific laws. Finally, it allows the economic computation of the entire plan, including lighting fixtures, electrical wiring and special pieces selected from an user-implementable database in more currencies.

LTB-LIGHT is, therefore, the ideal tool for:
  • dimensioning and color-choice for the lighting sources:
    • exterior - road, tunnel, urban landscapes, stadium, monuments, etc;
    • interior - showroom, auditorium, showcases, etc;
  • optimization and choice of glazed surfaces;
  • choice of the plaster based of the real color lighting effect;
  • study of the shadows, owned and brought;
  • checks and controls for television and glare;

Who needs it
LTB-LIGHT is a program dedicated to professionals working in the industry, architects, engineers, designers, builders, and their professional needs. To large industries who design lighting, institutions that determine the sites of application, the engineers charged in audits of facilities and verification of compliance of plant.