LTI Optics is always striving to improve customer support and provide you timely product updates and information to increase your productivity. If you have questions about your software, we invite you to review the sections above and check for new product downloads.

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You can customize any of the plots or data tables by creating a new style. The easiest way to do this is by copying an existing item that is similar and modifying it.

Location

All style documents are stored here:

C:\ProgramData\LTI Optics\Reports\Styles\

Copy Files

In the folder for each style, there will be an .xml file that specifies the configuration and a .png file that is a preview of the plot used in the program display. To create a new style, copy both of these files and give them a new name. Note that the first part of the name IntensityPlot - must remain since it defines the particular plot or table type that the files apply to.

Modify Files

Open the xml file in a text editor and edit the values based on what you want to change. This page contains details of what most elements do.

You can manually create a preview image, or you can export an image from the tool and use that as the preview image.

Pixels, Points and Vectors

The Photometric Reports software generates all graphics as vector artwork, so they can be scaled to very high resolution.

Throughout the configuration, some items will be referenced as pixel values (either thickness or position) and fonts as point values. These are not actual pixels, but coordinates used to create the vectors. Some items are referenced as a percentage of the overall plot size.

Color Systems

Colors can be specified in the following formats:

  - CIE_RGB: scaled 0-255

<type>CIE_RGB</type>
<value>255,255,255</value>

  - sRGB: scaled 0-255

<type>sRGB</type>
<value>255,255,255</value>

  - HSL: scaled 0-1

<type>HSL</type>
<value>0.5,0.25,0.1</value>

  - NULL_COLOR: can be used to turn off an element or make it fully transparent

<type>NULL_COLOR</type>
<value>0,0,0</value>

Font Settings

Fonts are specified using the following block. Font family is similar to html/css referencing. Font size is specified in points.

<fontstyle>
	<family>Tahoma</family>
	<fillcolor>
		<type>HSL</type>
		<value>0.5,0.25,0.1</value>
	</fillcolor>
	<strokecolor>
		<type>HSL</type>
		<value>0.5,0.25,0.1</value>
	</strokecolor>
	<strokewidth>2</strokewidth>
	<fontsize>10</fontsize>
</fontstyle>

Common Elements

Fill Color: sets the color of the fill, using any of the Color Systems above

<fillcolor>
	<type>HSL</type>
	<value>0.5,0.25,0.1</value>
</fillcolor>

Opacity: sets the opacity of the fill, scaled 0-1

<opacity>0.5</opacity>

Stroke Color: sets the color of the stroke, using any of the Color Systems above

<strokecolor>
	<type>HSL</type>
	<value>0.5,0.25,0.1</value>
</strokecolor>

Stroke Width: sets the width of the stroke in pixels

<strokewidth>3</strokewidth>

File Naming & Thumbnail Image

The file name must begin with the words "IntensityPlot" and can be followed by any other text. A thumbnail image with a square aspect ratio should be placed alongside the xml file with the same name.

View Size

The size, in pixels, of the view.

<viewdimensions>1000,1000<viewdimensions/>

Interpolation

Controls the interpolation of the plotted candela data between values in the data file. 1 is linear interpolation and 2 is spline interpolation.

<interpolation>2<interpolation/>

View Style

Controls the overall window background and border.

<viewstyle>
	<fillcolor>
		<type>sRGB</type>
		<value>255,255,255</value>
	</fillcolor>
	<strokecolor>
		<type>sRGB</type>
		<value>128,128,128</value>
	</strokecolor>
	<strokewidth>0</strokewidth>
	<opacity>0</opacity>
</viewstyle>

Border Style

Controls the plot background and border.

<borderstyle>
	<fillcolor>
		<type>sRGB</type>
		<value>255,255,255</value>
	</fillcolor>
	<strokecolor>
		<type>sRGB</type>
		<value>128,128,128</value>
	</strokecolor>
	<strokewidth>0</strokewidth>
	<opacity>0</opacity>
</borderstyle>

Legend

Controls the plot background and border.

The legend position can be left,right,top, or bottom.

The legend offset is a value in percent of the view extents that the legend is offset from the base position.

The columnwidths are in percent of the view extents. The first number is the angle text, the second is the line illustration.

<showlegend>true</showlegend>
<legend>
	<position>right</position>
	<offset>0,-0.3</offset>
	<columnwidths>0.08,0.04</columnwidths>
	<borderstyle>
		<fillcolor>
			<type>NULL_COLOR</type>
			<value>0,0,0</value>
		</fillcolor>
		<strokecolor>
			<type>SRGB</type>
			<value>0,0,0</value>
		</strokecolor>
		<strokewidth>1</strokewidth>
		<opacity>1</opacity>
	</borderstyle>
	<fontstyle>
		<family>Tahoma</family>
		<fillcolor>
			<type>CIE_RGB</type>
			<value>0,0,0</value>
		</fillcolor>
		<strokecolor>
			<type>CIE_RGB</type>
			<value>0,0,0</value>
		</strokecolor>
		<strokewidth>0</strokewidth>
		<fontsize>10</fontsize>
	</fontstyle>
</legend>

Half Plane

When set to true, all data is displayed on the right half of the plot. When set to false, the data is plotted on the left and right half in full plane pairs.

<halfplane>true<halfplane/>

Uplight

When set to true, uplight and downlight data is plotted. When set to false, only downlight data is plotted.

<uplight>true<uplight/>

Zoom To Data

When set to 0.0, the plots boundaries will be circular. When set to anything from 0.0 to 1.0, the plot will be zoomed to fit the data. At 1.0 the plot exactly fits the data, at 0.9, there is a 10% padding.

<zoomtofit>0.0<zoomtofit/>

Data Style Gradient

The style gradient specifies the start and end horizontal angle styles and then creates a gradient between this.

<seriesstylegradient>
	<dataseriesstyle>
		<fillcolor>
			<type>HSL</type>
			<value>0,1,0.5</value>
		</fillcolor>
		<strokecolor>
			<type>HSL</type>
			<value>0,1,0.5</value>
		</strokecolor>
		<strokewidth>2</strokewidth>
		<opacity>0</opacity>
	</dataseriesstyle>
	<dataseriesstyle>
		<fillcolor>
			<type>HSL</type>
			<value>0.83,1,0.5</value>
		</fillcolor>
		<strokecolor>
			<type>HSL</type>
			<value>0.83,1,0.5</value>
		</strokecolor>
		<strokewidth>2</strokewidth>
		<opacity>0</opacity>
	</dataseriesstyle>
</seriesstylegradient>

Data Style Override

The series style override allows you to explicitly set the style for individual horizontal planes of data. This element is not necessary. The <key> is the horizontal plane in degrees.

<seriesstyleoverride>
	<dataseriesstyle>
		<key>0</key>
		<value>
			<fillcolor>
				<type>SRGB</type>
				<value>255,230,0</value>
			</fillcolor>
			<strokecolor>
				<type>sRGB</type>
				<value>255,204,0</value>
			</strokecolor>
			<strokewidth>2</strokewidth>
			<opacity>.5</opacity>
		</value>
	</dataseriesstyle>
</seriesstyleoverride>

Title

The plot title text and style.

<title>Polar Plot</title>
<titlefont>
	<family>Tahoma</family>
	<fillcolor>
		<type>HSL</type>
		<value>0,0,0</value>
	</fillcolor>
	<strokecolor>
		<type>NULL_COLOR</type>
		<value>0,0,0</value>
	</strokecolor>
	<strokewidth>1</strokewidth>
	<fontsize>20</fontsize>
</titlefont>

Radius Markers

The radius markers are the circles at certain candela values.

<radiusmarkerstart>0.0</radiusmarkerstart>
<radiusmarkerincrement>0.0</radiusmarkerincrement>
<radiusmarkermajordivisor>1</radiusmarkermajordivisor>
<radiusmarkerminordivisor>1</radiusmarkerminordivisor>
<radiusminorfontstyle>
	<family>Tahoma</family>
	<fillcolor>
		<type>HSL</type>
		<value>0,0,0.8</value>
	</fillcolor>
	<strokecolor>
		<type>HSL</type>
		<value>0,0,0.8</value>
	</strokecolor>
	<strokewidth>0</strokewidth>
	<fontsize>12</fontsize>
</radiusminorfontstyle>
<radiusminorlinestyle>
	<fillcolor>
		<type>NULL_COLOR</type>
		<value>0,0,0</value>
	</fillcolor>
	<strokecolor>
		<type>HSL</type>
		<value>0,0,0.8</value>
	</strokecolor>
	<strokewidth>0.5</strokewidth>
	<opacity>1</opacity>
</radiusminorlinestyle>
<radiusmajorfontstyle>
	<family>Tahoma</family>
	<fillcolor>
		<type>HSL</type>
		<value>0,0,0.8</value>
	</fillcolor>
	<strokecolor>
		<type>HSL</type>
		<value>0,0,0.8</value>
	</strokecolor>
	<strokewidth>0</strokewidth>
	<fontsize>12</fontsize>
</radiusmajorfontstyle>
<radiusmajorlinestyle>
	<fillcolor>
		<type>NULL_COLOR</type>
		<value>0,0,0</value>
	</fillcolor>
	<strokecolor>
		<type>HSL</type>
		<value>0,0,.5</value>
	</strokecolor>
	<strokewidth>0.7</strokewidth>
	<opacity>1</opacity>
</radiusmajorlinestyle>

Angle Markers

The angle markers are the lines from the center of the plot for each vertical angle.

<anglemarkerincrement>0.174533</anglemarkerincrement>
<anglemarkermajordivisor>1</anglemarkermajordivisor>
<anglemarkerminordivisor>1</anglemarkerminordivisor>
<angleminorfontstyle>
	<family>Tahoma</family>
	<fillcolor>
		<type>HSL</type>
		<value>0,0,0.5</value>
	</fillcolor>
	<strokecolor>
		<type>HSL</type>
		<value>0,0,0.5</value>
	</strokecolor>
	<strokewidth>0</strokewidth>
	<fontsize>12</fontsize>
</angleminorfontstyle>
<angleminorlinestyle>
	<fillcolor>
		<type>NULL_COLOR</type>
		<value>0,0,0</value>
	</fillcolor>
	<strokecolor>
		<type>HSL</type>
		<value>0,0,0.5</value>
	</strokecolor>
	<strokewidth>0.5</strokewidth>
	<opacity>1</opacity>
</angleminorlinestyle>
<anglemajorfontstyle>
	<family>Tahoma</family>
	<fillcolor>
		<type>HSL</type>
		<value>0,0,0.7</value>
	</fillcolor>
	<strokecolor>
		<type>HSL</type>
		<value>0,0,0.7</value>
	</strokecolor>
	<strokewidth>0</strokewidth>
	<fontsize>12</fontsize>
</anglemajorfontstyle>
<anglemajorlinestyle>
	<fillcolor>
		<type>NULL_COLOR</type>
		<value>0,0,0</value>
	</fillcolor>
	<strokecolor>
		<type>HSL</type>
		<value>0,0,0.7</value>
	</strokecolor>
	<strokewidth>0.7</strokewidth>
	<opacity>1</opacity>
</anglemajorlinestyle>

Conventions

Having the correct Photometric Settings is critical to obtaining accurate results from Photopia. When you send a product for testing, the laboratory often determines the correct photometric angles, but when you are running Photopia it is something you must always be aware of. The angle sets are often broken down to vertical and horizontal angles, described below.

Vertical Angles

Vertical photometric angles go from directly below the fixture at 0 degrees to directly above at 180 degrees. The vertical angles that you choose are governed by the vertical distribution of your product. See the table below for information on the correct choice of vertical angles.

Direct Indirect Direct/Indirect
Distribution Light Directed Downward Light Directed Upward Light Directed Upward and Downward
Orientation Beam in -z direction Beam in +z direction Beam in -z direction
Vertical Angles 0-90 degrees 90-180 degrees 0-180 degrees

Horizontal Angles

The horizontal photometric angles that you will choose depend on the horizontal symmetric of your product. Fixtures can have four types of symmetry, as outlined in the table below. In Photopia it is important to choose the correct angle set based on the fixture symmetry because otherwise the output can become incorrect. Photopia always has data for the full 0-360 degrees, but averages down to the angle set that you choose. In the extreme case all 360 degrees are averaged together when you choose a horizontal angle of "0" only.

Axially Symmetric Quadrilaterally Symmetric Bilaterally Symmetric Completely Asymmetric
Examples Revolved Downlights Louvered Fluorescent "Asymmetric" Fluorescent Wallwash, Roadway Directional Tunnel Lighting
Lamp Orientation Along y axis
Outside U.S. Along x axis
Beam Direction Along +y axis
Horizontal Angles 0 degrees only 0-90 degrees 0-180 degrees 0-360 degrees

photometric angle conventions - North America

photometric angle conventions - World

Distribution

As Photopia has come to be more widely used in the architectural lighting industry, an increasing number of Photopia generated photometric files are being distributed by lighting manufacturers to their customers. By photometric files, we are referring to IES files in North America and TM-14 or EULUMDAT in other regions of the world.

The original intent of Photopia was to allow manufacturers to develop new designs more quickly and more cost effectively by evaluating their design ideas on their computer instead of building and testing each and every design alternative. Once the predicted design performance met the desired criteria, a prototype was built and physically tested. If the physical test did not meet the design requirements, then modifications would be made until the requirements were met. In many cases, this involved troubleshooting the design to ensure it was built to specifications, so that it matched what was modeled in Photopia.

Photopia is no longer only used in the development of new standard products. It is also used to model the performance of custom luminaires where the time from concept to installation does not allow for the classic product development cycle. Additionally, it is being used to model some existing products for which photometric testing was never before required. In these cases and others, some manufactures will distribute photometric files generated by Photopia.

Whenever a photometric file generated by Photopia is distributed to a customer, the data should be as accurate as possible. The consequences of the photometric data not being accurate can be very costly if you are called out to fix an installed job. The distribution of inaccurate data also hurts Photopia's reputation and therefore its overall value. So it is in everyone's interest to ensure photometric data generated by Photopia is as accurate as possible.

While Photopia's accuracy has been confirmed by our own experience as well as that of our customers, the accuracy is dependent upon several critical factors, including but not limited to the following:

  • You need to build exactly what you have modeled. If you compromise and choose a similar lamp or materials to the ones you will actually use, then you can expect differences between the predicted and measured photometry.
  • You need to understand your manufacturing tolerances for all of the parts in your design. You can create a range of Photopia models for the expected range of part configurations to gain a better understanding of the expected range of photometric performance.
  • You need to understand how to use Photopia well enough to properly setup your analysis so you get accurate results. This means properly orienting your luminaire, using the proper angle set in the candela distribution, using the proper number of reflections and the proper number of rays. See this link for more information about photometric standards.
  • Some issues such as thermal effects are completely ignored by Photopia, so if you have thermally sensitive lamps then you know that there will be differences between the simulated and measured efficiencies.
  • Anisotropic materials are only supported in Version 3.0. So if you use a material with a significant grained texture such as Alanod Miro 5, then the anisotropic properties need to be accurately modeled within Version 3.0.
  • For more information about the factors that affect the accuracy, see Appendix C of the User's Guide.

    Guidelines for Distributing Photometric Files:

    If you do distribute IES files generated by Photopia, then please follow this advice:

  • Leave the [TESTLAB] keyword in the IES file exactly how Photopia has defined it. This will ensure that your customers know that the file is the result of a simulation and not a physical test.
  • Remove all lines with the [OTHER] keyword. This information is useful to the optical designer, but not necessarily to your customers. This data could invite questions from your customers about details of the analysis that are not important. You can edit the IES file in Notepad.
  • You should review the total luminaire watts as defined in the IES file. This value is set according to the default lamp and assumed ballast wattage for the Photopia lamp model. If you have more accurate information about the total luminaire watts, then use it. See the end of Appendix B of the User's Guide for the IES file format.
  • Be sure to let your customers know that the data is simulated when you distribute the files either in your e-mail or on your website so that there is no misunderstanding about this issue later on.
  • Thank you for your attention to this issue.

    The Photopia Product Support Team

    Labs

    While Photopia is excellent for simulating photometry, there are often times when you must use a physical lab. These may include:

  • Confirmation of Photopia results
  • Significant thermal effects
  • Lamps or materials not available in Photopia Library
  • Physical testing required by code or specifying engineer
  • There are many labs available for photometric testing. We would recommend the following labs:

  • LightLab International - Phoenix, Arizona & Brisbane, Australia
  • Independent Testing Lab - Boulder, Colorado
  • Luminaire Testing Laboratory - Allentown, Pennsylvania
  • Lighting Sciences - Scottsdale, Arizona