Welcome to C_E Suite!
The C_E Suite is a software package for illuminance calculations that uses web-browser forms for input and output. This discussion covers the fundamantals for using these forms in C_E Suite. For additional discussion about illuminance calculations and features in C_E, including examples, read more here. For technical discussion about files etc, read more here.
The different forms in C_E share common elements such as layout and terminology. As examples, two forms are shown to the left: the Input form above the Points form. Each C_E form includes a title and under that a set of command buttons concerning the entire file or form, such as Open or eXit (in the red box). The next part of the form is the file name (in the blue box). The next area on the form displays the file contents entirely or in part (in the green box) for viewing but not for editting. Below that display is the portion of the form for changing the file contents. In the Input form, this is a simple set of selection boxes (in the gold box) providing choices limited to the files available, although other names can be entered.
In the Points form, shown below, the area for changing the file contents has two parts (in the gold box). The upper part is a number display and row of command buttons, and under that is a set of input fields for entering or editting the file contents. The number indicates the line# (the number on the far left side of the file display, green box) and can be changed using ^ or v to move one row in that direction, or by entering the desired line# and selecting # to jump to that line. The set of input fields will change to present choices appropriate for the selected line. In the figure the Points form is set to the header line, with all the header prompts shown below. When other lines in the points file are selected, the set of prompts is much simpler.
The commands in C_E forms are in two groups - for the upper set of buttons or for the lower set. For the upper set, the choices include New, Open, Run, Save, menU, eXit, View and ????. The choices presented in different forms vary, but the terms always have the same meaning. New and Open change what file is presented, and Save writes the currently displayed file contents to the indicated name. No file protection is provided in C_E, so files can/will be overwritten without notice. This applies to files that are saved and also files produced from Run commands. The Run command will first save the current file and then use it as input for running the appropriate software. Save will just save the file without running the software. Two other commands in the set, menU and eXit, close the form and proceed to the CE Menu or MDI Software Options. No check for "saved changed data" is provided. The final two commands open new browser windows. View will show output corresponding to the current file, while ???? leads to additional information such as this document.
For any command button or link, the capital letter can be used with Alt as shortcuts e.g. alt-U selects menU.
In C_E, the Input, MakeGrid and MakeRoad forms only have the one upper set of command buttons. The files associated with these applications will only reach a specific small size, which allows for simpler forms. In these forms, the set of input fields at the bottom of the form cover all the file contents, and the file that is Saved matches the information on the input fields, and the file display is then revised accordingly.
The commands for the lower set also have consistent meanings along with variability in availability. While none appear on the CE Input form, most appear on the Points form. These commands control the file display and editting of the file contents - sometimes just the current line, sometimes any part of the file. When included, line# is set automatically to the current line. Entering a number and selecting # will set the current line to that number or its closest match. The ^ and v buttons move the current line one row accordingly. The remaining commands include Add, Append, Insert, Modify and Remove. These refer to changing the file contents by adding another row at the end of the file, appending an entire file to the end, inserting a row just below the current one, modifying the current row to match the set of input fields, or removing the current row. Except for Append, these commands change just one row in the file, and which row is changed may depend on the current row. Append attaches the contents of the selected file to the end of the current one.
In C_E, whenever there is a lower row of command buttons, the file that is Saved matches the display in the middle of the form. The lower set of command buttons and the set of input fields below can be used to create or edit file contents, but the Modify command must be used to transfer the new information into the displayed file before that information can be Saved in the file. For those forms with the lower row of commands, the written file matches the display in the center section of the form. This may not match the information in the inputs fields at the bottom of the form. Entering new information into the input fields does not make any change to the contents of the file. To make a change to file contents, use the input fields and then the Modify button, check that the displayed file is as desired, and then Save. To confirm how a file was saved, open it. The browser's back button may retrieve earlier versions.
Illuminance is calculated "at a point on a surface" even if the surface is not real. In C_E, the specification of each point includes both a location in space for the point as well as a direction for the normal at that point.
The location of a point is specified using <x, y, z> coordinates in a typical arangement with +x considered "eastward", +y "northward", and +z as upward. The relationship between this C_E coordinate system and any real space is for the user to establish.
In C_E, each point can be considered as independent, but points can also be grouped together for convenience. For example, using MakeGrid to produce a group of points that are regularly spaced and have the same normal allows C_E to produce a statistical summary of the illuminance onto those grid points. This sumary includes maximum, minimum and uniformity values of illuminance, including locations where appropriate. Another example about grouping of points would be changing the normal for all points in a grid, say from horizontal illuminance (normal at <0,0,1>) to vertical facing in the direction of travel e.g. "north" (normal at <0,1,0>), which is much easier when using the C_E Points form with a group of points.
One powerful feature in C_E is the ability to combine files together into one greater file. Using the forms and in particular the Append command, files can be combined to build complex sets of points for use in the same calculation Run. For example, a combination of point grids could be used to calculate horizontal illuminance onto a roadway surface and also report verical illuminance at crosswalks and sidewalks from the same set of luminaire data.
In C_E, each point includes not only a location in <x,y,z> but also a normal in <i,j,k> to indicate the orientation of the (real or virtual) surface being considered. The term normal is used to describe the vector "perpendicular to a surface" at the specified point. This direction is used to determine the incident angle for illuminance, and so has a significant part in the calculations. In C_E, any point may have any direction for its normal. Further, the same location may have more than one normal, through repetition in the file with different entries having different normals.
Normals can be entered using any real numbers with any scale. When appropriate, C_E will "normalize" the normal (making its length = 1.0 while not changing the direction) and may save that revised set of values in files. Therefore, users can enter normal vectors in any numerical scale that represents the appropriate direction. For example, <0,1,2> will match <0,3,6> and <0, 0.447, 0.894> and C_E would convert and store any of the first set of values into the last one.
The simplest example is a horizontal surface which by definition has a vertical normal - but even then it may be going up or down. For vertical or sloped planar surfaces, the normal is typically set as perpendicular to the plane occupied by the points but can be specified as different. For lines and offsets, the normal at any point is set from the normal specified for the vertices at each end of each segment. For non-planar surfaces, the normal is taken as the perpendicular to the plane that is tangent to the non-planar surface at the specified point. Whne modelling complex shapes, the normal can be a very complicated element.
For lines and offsets, the normal may be specified for each vertex specified, and the utility will automatically adjust it using the applied spacing and "equal angle intervals" for each point between vertices. For roadways, the normal for all points is always set to <0,0,1> a.k.a. straight up. For grids, the normal for the points may be specified as usual for all points in the grid or it may be omitted, in which case it is set automatically to be perpendicular to the plane of the grid (using the RH rule and folding the P1-P2 line into P2-P3.) When the normal is specified once for all the points in the grid it will be shown in the header for the set of points. When the normal is specified for individual points, each point's location will be followed (on the same line in the data file) by the <i-j-k> value for the normal. To switch back and forth between defining normals as one surface or for each point, use the Normal button in the CE Point form. When switching to the 'as one surface' definition the normal for the first point is used. Therefore conversion from 'for each point' to 'as one surface' will remove data if any other points in the file have different normals. Normals may be individually adjusted in the CE Points form.
In lighting calculations, the characterization of light sources can be repeated for each individual luminaire or once for a group. A group can be effectively defined as a luminaire type, and then that designation can be applied to numerous individual luminaires or just one. In C_E, each type is defined around a photometric file with additional values that are collected into a file produced by the CE Types form. More than one type can be defined in a single types file, and the Append command is available in the CE Types form for combining separate files together.
In C_E, a luminaire type includes the key, to identify the type, and an optional decription, as well as values for rated lumens, light-loss factor (LLF) and multiplier. The key is any string that will be unique in the relevant calculation - only one type A per calculation allowed, and also types A1 and AA would be allowed. There are limitations on the characters that may be used in the key - stick to letters and numbers and conventional separators e.g. "_" for key values.
For each type, one photometric file is specified. The file must be in IES format with a copy in the IES photometry directory associated with C_E for a calculation to succeed. In the CE Types form, there is a list of such files for selection, although a different file can be entered. To get photometric files into the appropriate directory, use the MDI Files Utility discussed here and available from the MDI Software option page.
The values in a type designation are rated luemns, LLF and multiplier. The values can be any positive number. For rated lumens, a value of zero in the type file will be replaced in the calculation by the rated lumen value in the photometric file. The LLF and multiplier are used as multipliers for the rated lumens in the conventional way for rating luminaire performance.
In C_E, the lumen output of each luminaire is also adjusted by the count value associated with each luminaire location, as discussed below. In a C_E calculation, the values for LLF, multiplier and count will be multiplied together with the rated lumens to determine scaling for the photometric file data.
Luminaires are located in space using conventional <x,y,z> coordinates. These values' units are expected to match the units in the poiints file used in the calculation.
In C_E a location file may include more than one type of luminaire as well as more than one luminaire. For a calculation to succeed, all the types listed in a locations file must be defined in the associated types file. Keys must be distinct. The Count value associated with each location will scale that location's output, allowing for specifying multiple identical luminaires at once or for scaling output to model individual luminaire dimming. Aiming for each individual luminaire is discussed below. The Append command is available in the CE Locations form for combining separate files together.
In calculations, luminaires can be aimed using various systems. In C_E, aiming is done using the OTRS angles - Orient, Tilt, Roll and Spin - applied in turn to each luminaire using the CCE (counter-clockwise-from-East) procedure. This means that luminaires can be aimed individually, and that every luminaire carries its own aiming information in its definition. The aiming angles are entered in the C_E Locations form, with the default as 0 for each angle. When "earlier" angles are omitted and "later" ones included (as non-zero) the "earlier" angles are set to the default value of zero. Since C_E uses CCE, this default corresponds to a luminaire that is "facing" eastward (along the positive x-axis) and horizontal. Depending on the luminaire photometry, this corresponds to a floodlight aimed horizontally (type B photometry) or for example an area light (type C photometry) with its aperture horizontal and its photometric nadir pointed straight down. In each case the zero azimuth of the photometry is <1,0,0> a.k.a. eastward.
When a positive orient angle is applied, the luminaire is rotated through that angle in a counter-clockwise-seen-from-above direction, consistent with CCE. Therefore an orient value of 45 degreees corresponds to aiming the zero azimuth to <0.707,0.707,0> a.k.a. north-east, and a 90 degree orient to <0,1,0> a.k.a. north. Negative angles and angles over 360 degrees can be used as well.
The OTRS angles are applied in turn, so any orient angle is applied before any other aiming. Therefore the additional angles of Tilt, Roll and Spin can create complicated combinations for aiming. For a simple introduction to OTRS, the easiest example is of one's own head, nose pointing in the zero azimuth direction. A positive Orient angle corresponds to turning the head to the left. A positive Tilt angle corresponds to raising the chin. A positive Roll angle corresponds to leaning the top of the head toward the right shoulder. A Spin angle is effectively the same as an Orient angle, except it is applied after any-and-all-other aiming angles. For detailled information about using the OTRS angles in aiming luminaires, read more here or study the excellent diagrams and text here.
In the CE Input form the Run button in the top row will save the current version of the input file and then run the C_E program with that file for input. The software will in turn open each of the files listed in the input file, along with the referenced photometric files, and poduce output as one or more files. The name for the output file is taken from the input file's last line, with a '.ceo' extension. If the extension shown for the output is '.ces' then a summary of the output is also produced.
When the calculation is completed, the CE Input form appears with the title as a link and the View link shown in red. Either link will open a separate browser window to display the output as a '.ceo' or .'ces' file as appropriate. That browser's Save command can be used to save a copy of the file, including the header and footer lines added by C_E.
The C_E Suite includes more than the Input form and the three file-handling forms for Types, Locations and Points. There are also six utilities that produce or modify '.cep' files for use in C_E and another for handling files in the MDI Software system.
The makeGrid utility produces a planar grid of points spaced at specified intervals 'across' and 'along' in any plane and spacings and even for situations where "along" and "across" are not perpendicular. As shown on the CEP form, 'across' is the direction between Point #1 and Point #2, and 'along' is the direction between Point #2 and Point #3. All the grid points have a common normal which can be specified or provided automatically, in which case it is set perpendicular to both 'along' and 'across' and therefore to the plane of the grid.
The makePoly utility produces a planar grid inside a specified polygon with points spaced at specified intervals 'across' and 'along' in any plane and spacings. In these polygons "along" and "across" are always perpendicular with 'across' as the direction between the first and second vertices, and 'along' as the perpendicular direction in the plane of the polygon defined by the first three vertices. The perpendicular in the plane is on the same side of 'across' as the third vertex. All vertices after the first three will be projected onto the plane of the polygon when necessary to maintain a planar polygonal shape. All the grid points have a common normal which can be specified or provided automatically, in which case it is set perpendicular to both 'along' and 'across' and therefore to the plane of the polygon.
The makeLine utility uses specified vertices to describe line segments and then places points at the specified spacing along the line segments. The spacing is carried across vertices, to place the points as regularly as possible. As a result, whenever the line segment length is not an exact multiple of the spacing, the second (or later) vertex will not be included as a point. The normal can be specified at each vertex, and the utility will assign each point between vertices a normal based on the normals at the ends of that segment. When the two normals at the end of one segment are not parallel, the normals for the points between will be proportionally re-directed.
The makeOffs utility works with the Makeline utility to define sets of points along a line segment located at a specified offset from the line segment defined in the associated Makeline file. The makeOffs utility allows for selection of one Makeline file for establishing the base line and the specification of any number of offset starting points. From those points in turn the makeOffs utility will produce a set of vertices corresponding to line segments that are parallel to the corresponding segments in the base line, and combine them with the base line in one file suitable as input for the Makeline utility. Running the makeOffs output in Makeline will produce a file of points that corresponds to both the base line and every offset line. Normals are handled just the same as for the Makeline utility.
The makeRoad utility produces a grid of points that comply with the ANSI/IES RP-8 standard on roadway lighting for North America. The grid specifications are described in the RP-8 document and includes conditions on spacing and quantity of points. The utility takes the inputs specified, such as number of lanes and width of each lane, and defines a grid of points in the horizontal plane at grade with one corner at the origin - although the first point will be offset from <0,0> by half-steps in each direction. The normal is always upward.
The makeMods utility allows for .cep (points) files to be modified by rotating or moving the points as one group and then written to a new file. The points can be rotated a specified angle around a specified point and vertical axis, or moved a specified <x,y,z> distance. The rotation angle is measured in degrees in the horizontal plane with CCW (counter-clockwise seen from 'above') for positive values (corresponding to the Orient angle in OTRS). Rotation is made before any move. When points are rotated the associated normals are re-aimed accordingly. Therefore, for a vertical surface with <1,0,0> as its normal (a.k.a. east-facing), rotation by 135 degrees would result in a vertical surface with <-0.707,0.707,0> as its normal (a.k.a. northwest-facing).
The MDI Files Utility can be accessed from the page offering MDI Software options, shown immediately after signing in to the MDI Software system, or by using the eXit command in any C_E Suite form. This utility can upload files into the appropriate directories, as well as help in viewing and managing files in the MDI Software system.
The MDI Software system includes forms for viewing account information, also available through the MDI Software options page. If the C_E Suite programs become unavailable, check the account status there.
This brief discussion about C_E Suite has been intended to provide the fundamentals without too much detail. The C_E Suite has many features and characteristics not mentioned here. For more information, go here.