{"id":119378,"date":"2026-11-04T12:29:48","date_gmt":"2026-11-04T11:29:48","guid":{"rendered":"https:\/\/www.reerlighting.com\/?page_id=119378"},"modified":"2026-11-04T18:35:19","modified_gmt":"2026-11-04T17:35:19","slug":"cct-cri-and-ugr-2","status":"publish","type":"page","link":"https:\/\/www.reerlighting.com\/en\/resources-lux-calculator\/cct-cri-and-ugr-2\/","title":{"rendered":"Photometric Solid"},"content":{"rendered":"\n\n\t<section class=\"section\" id=\"section_422696951\">\n\t\t<div class=\"bg section-bg fill bg-fill  bg-loaded\" >\n\n\t\t\t\n\t\t\t\n\t\t\t\n\n\t\t<\/div>\n\n\t\t<div class=\"section-content relative\">\n\t\t\t\n\n<div class=\"row\"  id=\"row-901403843\">\n\n\n\t<div id=\"col-1940229724\" class=\"col small-12 large-12\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n\t<div id=\"text-2137736470\" class=\"text\">\n\t\t\n\n<h2>Photometric Solid Guide: Curves, Diagrams, and Digital Files<\/h2>\n\t\t\n<style>\n#text-2137736470 {\n  text-align: left;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n<\/div>\n<div class=\"row\"  id=\"row-1050632832\">\n\n\n\t<div id=\"col-2120638934\" class=\"col pb-0 small-12 large-12\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<p style=\"text-align: justify;\" data-path-to-node=\"3\"><span class=\"\">To accurately predict how light will behave in space and on architectural surfaces,<\/span><span class=\"\">it is not enough to know the lumens emitted by a luminaire.<\/span><span class=\"\">It is necessary to precisely map its directional distribution.<\/span><span class=\"\"><br \/>This geometric and energetic survey generates the <\/span><b data-path-to-node=\"3\" data-index-in-node=\"272\">Photometric Solid<\/b>, the fundamental tool that allows planners and lighting designers to simulate lighting in virtual environments (using software such as Dialux or Relux).<\/p>\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n<\/div>\n\n\t\t<\/div>\n\n\t\t\n<style>\n#section_422696951 {\n  padding-top: 30px;\n  padding-bottom: 30px;\n}\n<\/style>\n\t<\/section>\n\t\n\t<section class=\"section\" id=\"section_928934429\">\n\t\t<div class=\"bg section-bg fill bg-fill  bg-loaded\" >\n\n\t\t\t\n\t\t\t\n\t\t\t\n\n\t\t<\/div>\n\n\t\t<div class=\"section-content relative\">\n\t\t\t\n\n<div class=\"row\"  id=\"row-1657122438\">\n\n\n\t<div id=\"col-259431869\" class=\"col col-block-effetti small-12 large-12\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<h2 class=\"title1 title-high\">What is the Photometric Solid?<\/h2>\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n<\/div>\n<div class=\"row\"  id=\"row-1290121718\">\n\n\n\t<div id=\"col-585133362\" class=\"col col-block-effetti medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<p data-path-to-node=\"6\">The photometric solid is the three-dimensional representation of the <b data-path-to-node=\"6\" data-index-in-node=\"65\">luminous intensity<\/b> (measured in candelas) emitted by a light source in all directions in space.<\/p>\r\n<p data-path-to-node=\"7\">It is generated in the laboratory using an instrument called a <b data-path-to-node=\"7\" data-index-in-node=\"64\">goniophotometer<\/b>, which rotates the turned-on device (or a sensor around it) and measures the candela value for each solid angle.<span class=\"\">The three-dimensional envelope obtained by combining all the intensity vectors is the photometric solid.<\/span> Its shape determines the visual &#8220;imprint&#8221; that the light will leave on the architecture.<\/p>\n\n\t\t<\/div>\n\t\t\n<style>\n#col-585133362 > .col-inner {\n  padding: 0px 0px 0px 0px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n\t<div id=\"col-696647263\" class=\"col col-block-effetti medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner text-center\"  >\n\t\t\t\n\t\t\t\n\n\t<div class=\"img has-hover x md-x lg-x y md-y lg-y\" id=\"image_143505115\">\n\t\t\t\t\t\t\t\t<div class=\"img-inner dark\" >\n\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1300\" height=\"1000\" src=\"https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/Solido_fotometrico_ReeR-1.jpg\" class=\"attachment-original size-original\" alt=\"\" srcset=\"https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/Solido_fotometrico_ReeR-1.jpg 1300w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/Solido_fotometrico_ReeR-1-300x231.jpg 300w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/Solido_fotometrico_ReeR-1-1024x788.jpg 1024w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/Solido_fotometrico_ReeR-1-768x591.jpg 768w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/Solido_fotometrico_ReeR-1-500x385.jpg 500w\" sizes=\"auto, (max-width: 1300px) 100vw, 1300px\" \/>\t\t\t\t\t\t\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n<style>\n#image_143505115 {\n  width: 100%;\n}\n<\/style>\n\t<\/div>\n\t\n\n\n\t\t<\/div>\n\t\t\n<style>\n#col-696647263 > .col-inner {\n  padding: 0px 0px 0px 0px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n<\/div>\n\n\t\t<\/div>\n\n\t\t\n<style>\n#section_928934429 {\n  padding-top: 0px;\n  padding-bottom: 0px;\n  min-height: 80px;\n}\n<\/style>\n\t<\/section>\n\t\n\t<section class=\"section\" id=\"section_61502012\">\n\t\t<div class=\"bg section-bg fill bg-fill  bg-loaded\" >\n\n\t\t\t\n\t\t\t\n\t\t\t\n\n\t\t<\/div>\n\n\t\t<div class=\"section-content relative\">\n\t\t\t\n\n<div class=\"row\"  id=\"row-175023351\">\n\n\n\t<div id=\"col-1245619433\" class=\"col col-block-effetti small-12 large-12\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<h2 class=\"title1 title-high\">From 3D to 2D: The Polar Diagram (Photometric Curve)<\/h2>\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n<\/div>\n<div class=\"row\"  id=\"row-1730629498\">\n\n\n\t<div id=\"col-1923244701\" class=\"col col-block-effetti medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<p data-path-to-node=\"10\">Because a 3D volume is complex to interpret on a paper datasheet or monitor, the solid is &#8220;sliced&#8221; along vertical and horizontal planes. The resulting two-dimensional cross-section is the <b data-path-to-node=\"10\" data-index-in-node=\"206\">Photometric Curve<\/b>, usually represented in a <b data-path-to-node=\"10\" data-index-in-node=\"257\">polar diagram<\/b>.<\/p>\r\n<p data-path-to-node=\"11\">The most widely used international reference system for technical lighting is the <b class=\"\" data-path-to-node=\"11\" data-index-in-node=\"89\">C-Gamma system (<em><span class=\"math-inline\" data-math=\"C-gamma\" data-index-in-node=\"106\">C-\u03b3<\/span><\/em>)<\/b>:<\/p>\r\n<ul data-path-to-node=\"12\">\r\n<li>\r\n<p data-path-to-node=\"12,0,0\">The <b data-path-to-node=\"12,0,0\" data-index-in-node=\"8\">C (0\u00b0-360\u00b0)<\/b> planes rotate around the vertical axis of the fixture.<\/p>\r\n<\/li>\r\n<li>\r\n<p data-path-to-node=\"12,1,0\">The <b class=\"\" data-path-to-node=\"12,1,0\" data-index-in-node=\"11\">Gamma (<em>\u03b3<\/em> 0\u00b0-180\u00b0)<\/b> angles indicate the inclination of the beam from the vertical (where 0\u00b0 is the light pointed straight down &#8211; <i data-path-to-node=\"12,1,0\" data-index-in-node=\"145\">Nadir<\/i>).<\/p>\r\n<\/li>\r\n<\/ul>\r\n<p data-path-to-node=\"13\">In datasheets, the photometric curve typically shows two main planes:<\/p>\r\n<ol start=\"1\" data-path-to-node=\"14\">\r\n<li>\r\n<p data-path-to-node=\"14,0,0\"><b data-path-to-node=\"14,0,0\" data-index-in-node=\"0\">Plane C0 &#8211; C180 (yellow line on the ReeR website):<\/b> Cross-section or longitudinal axis of the luminaire.<\/p>\r\n<\/li>\r\n<li>\r\n<p data-path-to-node=\"14,1,0\"><b data-path-to-node=\"14,1,0\" data-index-in-node=\"0\">Plane C90 &#8211; C270 (black line on the ReeR website):<\/b> Section orthogonal to the previous one.<\/p>\r\n<\/li>\r\n<\/ol>\n\n\t\t<\/div>\n\t\t\n<style>\n#col-1923244701 > .col-inner {\n  padding: 0px 0px 0px 0px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n\t<div id=\"col-607291931\" class=\"col col-block-effetti medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner text-center\"  >\n\t\t\t\n\t\t\t\n\n\t<div class=\"img has-hover x md-x lg-x y md-y lg-y\" id=\"image_1511727272\">\n\t\t\t\t\t\t\t\t<div class=\"img-inner dark\" >\n\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1000\" height=\"1000\" src=\"https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6360806.jpg\" class=\"attachment-large size-large\" alt=\"\" srcset=\"https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6360806.jpg 1000w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6360806-300x300.jpg 300w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6360806-150x150.jpg 150w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6360806-768x768.jpg 768w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6360806-500x500.jpg 500w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6360806-100x100.jpg 100w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\" \/>\t\t\t\t\t\t\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n<style>\n#image_1511727272 {\n  width: 70%;\n}\n<\/style>\n\t<\/div>\n\t\n\n\n\t\t<\/div>\n\t\t\n<style>\n#col-607291931 > .col-inner {\n  padding: 0px 0px 0px 0px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n\t<div id=\"col-1520487991\" class=\"col col-block-effetti small-12 large-12\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<blockquote>\r\n<p>If the device has a perfectly circular optics, the two lines will overlap into one.<\/p>\r\n<\/blockquote>\n\n\t\t<\/div>\n\t\t\n<style>\n#col-1520487991 > .col-inner {\n  padding: 0px 0px 0px 0px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n<\/div>\n\n\t\t<\/div>\n\n\t\t\n<style>\n#section_61502012 {\n  padding-top: 0px;\n  padding-bottom: 0px;\n  min-height: 80px;\n}\n<\/style>\n\t<\/section>\n\t\n\t<section class=\"section\" id=\"section_1360486258\">\n\t\t<div class=\"bg section-bg fill bg-fill  bg-loaded\" >\n\n\t\t\t\n\t\t\t\n\t\t\t\n\n\t\t<\/div>\n\n\t\t<div class=\"section-content relative\">\n\t\t\t\n\n<div class=\"row\"  id=\"row-972820477\">\n\n\n\t<div id=\"col-178579299\" class=\"col col-block-effetti small-12 large-12\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<h2 class=\"title1 title-high\">Types of Optical Distribution<\/h2>\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n<\/div>\n<div class=\"row\"  id=\"row-528721042\">\n\n\n\t<div id=\"col-1130864032\" class=\"col col-block-effetti small-12 large-12\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<p data-path-to-node=\"19\">The shape of the solid defines the optical classification of the luminaire, a vital parameter in choosing the right product for each outdoor or indoor application.<\/span><\/p>\n\n\t\t<\/div>\n\t\t\n<style>\n#col-1130864032 > .col-inner {\n  padding: 0px 0px 0px 0px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n\t<div id=\"col-608530232\" class=\"col col-block-effetti medium-3 small-12 large-3\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n\t<div class=\"img has-hover x md-x lg-x y md-y lg-y\" id=\"image_1651374772\">\n\t\t\t\t\t\t\t\t<div class=\"img-inner dark\" >\n\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1000\" height=\"1000\" src=\"https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_MTK0003.jpg\" class=\"attachment-large size-large\" alt=\"\" srcset=\"https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_MTK0003.jpg 1000w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_MTK0003-300x300.jpg 300w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_MTK0003-150x150.jpg 150w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_MTK0003-768x768.jpg 768w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_MTK0003-500x500.jpg 500w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_MTK0003-100x100.jpg 100w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\" \/>\t\t\t\t\t\t\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n<style>\n#image_1651374772 {\n  width: 100%;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t<div id=\"text-909611080\" class=\"text\">\n\t\t\n\n<p><strong>Rotosymmetric<\/strong><\/p>\n\t\t\n<style>\n#text-909611080 {\n  text-align: center;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t\t<\/div>\n\t\t\n<style>\n#col-608530232 > .col-inner {\n  padding: 0px 0px 0px 0px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n\t<div id=\"col-929407534\" class=\"col col-block-effetti medium-3 small-12 large-3\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n\t<div class=\"img has-hover x md-x lg-x y md-y lg-y\" id=\"image_813804213\">\n\t\t\t\t\t\t\t\t<div class=\"img-inner dark\" >\n\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1000\" height=\"1000\" src=\"https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6361188.jpg\" class=\"attachment-large size-large\" alt=\"\" srcset=\"https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6361188.jpg 1000w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6361188-300x300.jpg 300w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6361188-150x150.jpg 150w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6361188-768x768.jpg 768w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6361188-500x500.jpg 500w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6361188-100x100.jpg 100w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\" \/>\t\t\t\t\t\t\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n<style>\n#image_813804213 {\n  width: 100%;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t<div id=\"text-1967632174\" class=\"text\">\n\t\t\n\n<p><strong>A<\/strong><strong>symmetric<\/strong><\/p>\n\t\t\n<style>\n#text-1967632174 {\n  text-align: center;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t\t<\/div>\n\t\t\n<style>\n#col-929407534 > .col-inner {\n  padding: 0px 0px 0px 0px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n\t<div id=\"col-668652778\" class=\"col col-block-effetti medium-3 small-12 large-3\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n\t<div class=\"img has-hover x md-x lg-x y md-y lg-y\" id=\"image_183004820\">\n\t\t\t\t\t\t\t\t<div class=\"img-inner dark\" >\n\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1000\" height=\"1000\" src=\"https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6361397.jpg\" class=\"attachment-large size-large\" alt=\"\" srcset=\"https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6361397.jpg 1000w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6361397-300x300.jpg 300w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6361397-150x150.jpg 150w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6361397-768x768.jpg 768w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6361397-500x500.jpg 500w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6361397-100x100.jpg 100w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\" \/>\t\t\t\t\t\t\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n<style>\n#image_183004820 {\n  width: 100%;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t<div id=\"text-555720692\" class=\"text\">\n\t\t\n\n<p><strong>Elliptical<\/strong><\/p>\n\t\t\n<style>\n#text-555720692 {\n  text-align: center;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t\t<\/div>\n\t\t\n<style>\n#col-668652778 > .col-inner {\n  padding: 0px 0px 0px 0px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n\t<div id=\"col-1035784406\" class=\"col col-block-effetti medium-3 small-12 large-3\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n\t<div class=\"img has-hover x md-x lg-x y md-y lg-y\" id=\"image_1979629537\">\n\t\t\t\t\t\t\t\t<div class=\"img-inner dark\" >\n\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1000\" height=\"1000\" src=\"https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6360806.jpg\" class=\"attachment-large size-large\" alt=\"\" srcset=\"https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6360806.jpg 1000w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6360806-300x300.jpg 300w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6360806-150x150.jpg 150w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6360806-768x768.jpg 768w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6360806-500x500.jpg 500w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/POLAR_REER_6360806-100x100.jpg 100w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\" \/>\t\t\t\t\t\t\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n<style>\n#image_1979629537 {\n  width: 100%;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t<div id=\"text-3270788843\" class=\"text\">\n\t\t\n\n<p><strong>Street (&#8220;Batwing&#8221;)<\/strong><\/p>\n\t\t\n<style>\n#text-3270788843 {\n  text-align: center;\n}\n<\/style>\n\t<\/div>\n\t\n\n\t\t<\/div>\n\t\t\n<style>\n#col-1035784406 > .col-inner {\n  padding: 0px 0px 0px 0px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n\t<div id=\"col-408426899\" class=\"col col-block-effetti small-12 large-12\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<table data-path-to-node=\"19\">\r\n<thead>\r\n<tr>\r\n<td><strong>Optics Type<\/strong><\/td>\r\n<td><strong>Solid Shape<\/strong><\/td>\r\n<td><strong>Typical Lighting Application<\/strong><\/td>\r\n<\/tr>\r\n<\/thead>\r\n<tbody>\r\n<tr>\r\n<td><span data-path-to-node=\"19,1,0,0\"><b data-path-to-node=\"19,1,0,0\" data-index-in-node=\"0\">Rotosymmetric<\/b><\/br> (Spot \/ Flood)<\/span><\/td>\r\n<td><span data-path-to-node=\"19,1,1,0\">A cone or &#8220;balloon&#8221; perfectly symmetrical about the vertical axis (C0 = C90).<\/span><\/td>\r\n<td><span data-path-to-node=\"19,1,2,0\">Recessed spotlights, downlights, accents on columns, lighting tall and narrow facades.<\/span><\/td>\r\n<\/tr>\r\n<tr>\r\n<td><span data-path-to-node=\"19,2,0,0\"><b data-path-to-node=\"19,2,0,0\" data-index-in-node=\"0\">Asymmetrical<\/b><\/span><\/td>\r\n<td><span data-path-to-node=\"19,2,1,0\">The solid is unbalanced forward, &#8220;cutting&#8221; the light backwards.<\/span><\/td>\r\n<td><span data-path-to-node=\"19,2,2,0\">Wall-mounted spotlights for facades (wallwashers), courtyard lighting, signage, where it is necessary to avoid light dispersion behind the device.<\/span><\/td>\r\n<\/tr>\r\n<tr>\r\n<td><span data-path-to-node=\"19,3,0,0\"><b data-path-to-node=\"19,3,0,0\" data-index-in-node=\"0\">Elliptical<\/b><\/span><\/td>\r\n<td><span data-path-to-node=\"19,3,1,0\">Narrow on one axis (e.g., 10\u00b0) and wide on the other axis (e.g., 45\u00b0), forming an oval blade.<\/span><\/td>\r\n<td><span data-path-to-node=\"19,3,2,0\">Grazing on textured walls, cornice lighting, enhancing linear architectural elements.<\/span><\/td>\r\n<\/tr>\r\n<tr>\r\n<td><span data-path-to-node=\"19,4,0,0\"><b data-path-to-node=\"19,4,0,0\" data-index-in-node=\"0\">Batwing<\/b><\/span><\/td>\r\n<td><span data-path-to-node=\"19,4,1,0\">A complex &#8220;batwing&#8221; shape, very wide transversely and narrow from the front.<\/span><\/td>\r\n<td><span data-path-to-node=\"19,4,2,0\">Street lighting, pedestrian walkways, large parking lots (optimizes the spacing between poles, reducing glare).<\/span><\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\n\n\t\t<\/div>\n\t\t\n<style>\n#col-408426899 > .col-inner {\n  padding: 0px 0px 0px 0px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n<\/div>\n\n\t\t<\/div>\n\n\t\t\n<style>\n#section_1360486258 {\n  padding-top: 0px;\n  padding-bottom: 0px;\n  min-height: 80px;\n}\n<\/style>\n\t<\/section>\n\t\n\t<section class=\"section\" id=\"section_1490652452\">\n\t\t<div class=\"bg section-bg fill bg-fill  bg-loaded\" >\n\n\t\t\t\n\t\t\t\n\t\t\t\n\n\t\t<\/div>\n\n\t\t<div class=\"section-content relative\">\n\t\t\t\n\n<div class=\"row\"  id=\"row-184327897\">\n\n\n\t<div id=\"col-1593817908\" class=\"col col-block-effetti small-12 large-12\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<h2 class=\"title1 title-high\">Digital Formats: LDT and IES Files<\/h2>\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n<\/div>\n<div class=\"row\"  id=\"row-1013698201\">\n\n\n\t<div id=\"col-1930137496\" class=\"col col-block-effetti medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<p data-path-to-node=\"22\"><span class=\"\">To be calculated by design software,<\/span> the entire database of angular coordinates and intensity of the photometric solid is compressed into standardized text files. The two universal formats are:<\/p>\r\n<ul data-path-to-node=\"23\">\r\n<li>\r\n<p data-path-to-node=\"23,0,0\"><b data-path-to-node=\"23,0,0\" data-index-in-node=\"0\">EULUMDAT (.ldt):<\/b> This is the European reference standard. It contains not only the candela matrix, but also the physical data of the device (dimensions of the emitting surface), the electrical power (W), and the nominal and actual luminous flux.<\/p>\r\n<\/li>\r\n<li>\r\n<p data-path-to-node=\"23,1,0\"><b data-path-to-node=\"23,1,0\" data-index-in-node=\"0\">IESNA (.ies):<\/b><span class=\"\"> This is the North American standard.<\/span><span class=\"\"> Similar in concept,<\/span><span class=\"\"> it differs slightly in its computer structure and the management of multiplication factors.<\/span><\/p>\r\n<\/li>\r\n<\/ul>\n\n\t\t<\/div>\n\t\t\n<style>\n#col-1930137496 > .col-inner {\n  padding: 0px 0px 0px 0px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n\t<div id=\"col-238506420\" class=\"col col-block-effetti medium-6 small-12 large-6\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n\t<div class=\"img has-hover x md-x lg-x y md-y lg-y\" id=\"image_2028974416\">\n\t\t\t\t\t\t\t\t<div class=\"img-inner dark\" >\n\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1020\" height=\"527\" src=\"https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/dialux-simulazione-illuminotecnica-1024x529.jpg\" class=\"attachment-large size-large\" alt=\"\" srcset=\"https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/dialux-simulazione-illuminotecnica-1024x529.jpg 1024w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/dialux-simulazione-illuminotecnica-300x155.jpg 300w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/dialux-simulazione-illuminotecnica-768x397.jpg 768w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/dialux-simulazione-illuminotecnica-1536x794.jpg 1536w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/dialux-simulazione-illuminotecnica-500x258.jpg 500w, https:\/\/www.reerlighting.com\/wp-content\/uploads\/2026\/11\/dialux-simulazione-illuminotecnica.jpg 1915w\" sizes=\"auto, (max-width: 1020px) 100vw, 1020px\" \/>\t\t\t\t\t\t\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n<style>\n#image_2028974416 {\n  width: 100%;\n}\n<\/style>\n\t<\/div>\n\t\n\n\n\t\t<\/div>\n\t\t\n<style>\n#col-238506420 > .col-inner {\n  padding: 0px 0px 0px 0px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n\t<div id=\"col-100766177\" class=\"col col-block-effetti small-12 large-12\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<blockquote>\r\n<p><b data-path-to-node=\"24.0\" data-index-in-node=\"0\">Absolute Photometry and LED Technology:<\/b> In traditional discharge lamps, photometric files were &#8220;relative&#8221; (calculated on a theoretical flux of 1,000 lumens) because the same optic could accommodate bulbs of different wattages. Today, with LED architecture, the optic and the source form an integrated, inseparable system. <br \/>Our fixture measurements use <b data-path-to-node=\"24.0\" data-index-in-node=\"377\">Absolute Photometry<\/b>: the lumens and candelas described in the LDT file correspond exactly to the actual performance of that specific fixture, eliminating any margin of error in lighting design calculations.<\/p>\r\n<\/blockquote>\n\n\t\t<\/div>\n\t\t\n<style>\n#col-100766177 > .col-inner {\n  padding: 0px 0px 0px 0px;\n}\n<\/style>\n\t<\/div>\n\n\t\n\n<\/div>\n\n\t\t<\/div>\n\n\t\t\n<style>\n#section_1490652452 {\n  padding-top: 0px;\n  padding-bottom: 0px;\n  min-height: 80px;\n}\n<\/style>\n\t<\/section>\n\t\n\t<section class=\"section\" id=\"section_680011735\">\n\t\t<div class=\"bg section-bg fill bg-fill  bg-loaded\" >\n\n\t\t\t\n\t\t\t\n\t\t\t\n\n\t\t<\/div>\n\n\t\t<div class=\"section-content relative\">\n\t\t\t\n\n<div class=\"row\"  id=\"row-719650072\">\n\n\n\t<div id=\"col-2075343127\" class=\"col col-block-effetti small-12 large-12\"  >\n\t\t<div class=\"col-inner\"  >\n\t\t\t\n\t\t\t\n\n<h2 class=\"title1 title-high\">Summary: The Heart of Lighting Design<\/h2>\r\n\t<div id=\"gap-16011906\" class=\"gap-element clearfix\" style=\"display:block; height:auto;\">\n\t\t\n<style>\n#gap-16011906 {\n  padding-top: 20px;\n}\n<\/style>\n\t<\/div>\n\t\r\n\r\n<blockquote>\r\n<div class=\"container\">\r\n<div id=\"model-response-message-contentr_15da3d882e405dc9\" class=\"markdown markdown-main-panel md-content enable-luminous-fast-follows enable-updated-hr-color stronger\" dir=\"ltr\" aria-busy=\"false\" aria-live=\"polite\">\r\n<p data-path-to-node=\"27\"><span class=\"\">The photometric solid is the bridge between product engineering and the art of architectural design.<\/span><span class=\"\">Relying on photometric files (.ldt) that are accurate, up-to-date, and measured with minimal tolerances is the only way to ensure that the calculated lux Virtually in the design phase, they correspond exactly to the span measured on site once installation is complete, complying with regulatory constraints (CEI EN 12464) and enhancing the architecture.\r\n\r\n<\/div>\r\n<\/div>\r\n<\/blockquote>\n\n\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\n<\/div>\n\n\t\t<\/div>\n\n\t\t\n<style>\n#section_680011735 {\n  padding-top: 0px;\n  padding-bottom: 0px;\n  min-height: 80px;\n}\n<\/style>\n\t<\/section>\n\t\n\t<div id=\"gap-1636173354\" class=\"gap-element clearfix\" style=\"display:block; height:auto;\">\n\t\t\n<style>\n#gap-1636173354 {\n  padding-top: 70px;\n}\n<\/style>\n\t<\/div>\n\t\n\n\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":10706,"featured_media":0,"parent":119361,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"page-blank.php","meta":{"inline_featured_image":false,"footnotes":""},"class_list":["post-119378","page","type-page","status-publish","hentry"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.4 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>ReeR - Photometric Solid<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.reerlighting.com\/en\/resources-lux-calculator\/cct-cri-and-ugr-2\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"ReeR - Photometric Solid\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.reerlighting.com\/en\/resources-lux-calculator\/cct-cri-and-ugr-2\/\" \/>\n<meta property=\"og:site_name\" content=\"ReeR\" \/>\n<meta property=\"article:modified_time\" content=\"2026-11-04T17:35:19+00:00\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.reerlighting.com\/en\/resources-lux-calculator\/cct-cri-and-ugr-2\/\",\"url\":\"https:\/\/www.reerlighting.com\/en\/resources-lux-calculator\/cct-cri-and-ugr-2\/\",\"name\":\"ReeR - 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