{"id":298,"date":"2009-10-29T13:49:35","date_gmt":"2009-10-29T13:49:35","guid":{"rendered":"https:\/\/www.cg-blog.com\/?p=298"},"modified":"2013-04-15T09:23:57","modified_gmt":"2013-04-15T09:23:57","slug":"vray-caustics-tutorial","status":"publish","type":"post","link":"https:\/\/www.cg-blog.com\/index.php\/2009\/10\/29\/vray-caustics-tutorial.htm","title":{"rendered":"V-Ray caustics \u00e2\u20ac\u201c Simple Tutorial to understand it"},"content":{"rendered":"<p><img decoding=\"async\" src=\"https:\/\/www.cg-blog.com\/wp-content\/uploads\/2010\/08\/io-caustiche.jpg\" alt=\"caustiche vray\" width=\"599px\" \/><\/p>\n<p style=\"text-align: center;\">*<\/p>\n<p style=\"text-align: center;\"><span style=\"color: #ff0000;\"><strong>This post has been updated<\/strong><\/span> &gt; <strong><a href=\"https:\/\/www.cg-blog.com\/index.php\/2011\/12\/27\/vray-caustics-setup-tutorial.htm\">V-Ray Caustics V2<\/a>\u00c2\u00a0!<\/strong><\/p>\n<p style=\"text-align: center;\">*<\/p>\n<p>I went on holiday, I spent two wonderful weeks in Zante &#8211; thinking in a <a href=\"https:\/\/www.cg-blog.com\/index.php\/2009\/11\/05\/simulation-sea-vray.htm\">V-Ray Sea Simulation<\/a> &#8211; and I must confess it: these days I was particularly attracted to those amazing play of light that you see on the bottom of the sea and swimming pools.<\/p>\n<p>This is a physical effect that takes the name of &#8220;Caustics&#8221; and you have probably already read somewhere that you can simulate this effect with V-Ray. Let&#8217;s see how.<\/p>\n<p>The light passes through a curvee and transparent body (glass, water ..) , so the light will tend to concentrate it in some areas. (Read a <a href=\"http:\/\/www.mathiesonfacer.com\/tutorials\/UnderstandingCaustics\/index.html\" target=\"_blank\">full explanation of caustic<\/a> )<\/p>\n<p>Very often we create material &#8220;Water&#8221; material using &#8220;Affect shadows&#8221; option. In this way\u00c2\u00a0the light passes through the object. If you do not want the caustics this \u00c2\u00a0is a good solution.\u00c2\u00a0If <strong>you want to simulate the caustics<\/strong> mark &#8220;on&#8221; here:<\/p>\n<ul>\n<li>Panel rendering (F10) <strong>&gt; Indirect Illumination&gt; V-Ray Caustics &gt; ON [X]<\/strong><\/li>\n<\/ul>\n<p>Here a little explainiation of the main 4 parameters you&#8217;ll find there:<\/p>\n<ul>\n<li><strong>Multiplier<\/strong>: caustic intensity \u00c2\u00a0(1,0 default = ok)<\/li>\n<li><strong>Search dist<\/strong>: projection distance (..follow the tutorial)<\/li>\n<li><strong>Max photons<\/strong>: maximum number of photons used to calculate\u00c2\u00a0(10 = ok)<\/li>\n<li><strong>Max density<\/strong>: Resolution limit (0,0 default = ok)<\/li>\n<\/ul>\n<p><strong>CAUSTIC SUBDIVISION parameter:<\/strong><br \/>\nIt &#8216;important to manage the details of the caustic. It is governed by the value &#8220;Caustic subdivs.&#8221; you can find by clicking on Light Setting in:<\/p>\n<p><strong>&#8211; Rendering panel &gt; Setting &gt; Light Setting (at bottom)<\/strong> and checking the light: <strong>Direct Sun<\/strong>, in this case.<\/p>\n<blockquote><p>Note: In this V-Ray version I use \u00c2\u00a0I prefer to use &#8220;direct light&#8221; because it works better than VRaySun<\/p><\/blockquote>\n<p>(In the attached file, &#8220;Caustic subdivs.&#8221; setting is 30000. It&#8217;s high enough to get sharped caustics. Attention: for your first test you can start using &#8220;3000&#8221;.)<\/p>\n<p>As you know I love simple explanations, and especially love the &#8220;results&#8221; without too many technical and mental complications, so let&#8217;s concentrate on the main actor. Do you know who is?<\/p>\n<p><strong>&gt;&gt;&gt; It&#8217;s the WATER SURFACE!<br \/>\n&#8220;Create a good water surface in order to get a realistic caustics effect&#8221; <\/strong><\/p>\n<p>Without a suitable surface the effect is never pleasant. Surely there are many ways to make a good surface that simulates the water, in this tutorial I do so:<\/p>\n<ul>\n<li>I create a box with a high number of subdivisions (1cm thick)<\/li>\n<li>I apply the Noise modifier with &#8220;fractal&#8221; active (Z = 1cm)<\/li>\n<\/ul>\n<p>You just <strong>turn on<\/strong> the caustics and assign to Search. dist. a suitable distance to let the caustics &#8220;reach&#8221; the bottom. (Eg.: If the pool is 200cm deep, setup Distance search = 300cm, this value will be more than sufficient.)<\/p>\n<p>In this render I just use &#8220;affect shadows&#8221;: It seems the sun doesn&#8217;t penetrate the water!<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" src=\"http:\/\/www.grafica3dblog.it\/immagini\/caustic-blog2.jpg\" alt=\"caustiche vray\" width=\"476\" height=\"234\" \/><\/p>\n<p>But if we activate the caustics, thus allowing the light to cross the water, generate caustics, projecting towards the bottom and upwards &#8230; then the result changes! (Unfortunately, also the rendering time)<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" src=\"http:\/\/www.grafica3dblog.it\/immagini\/caustic-blog1.jpg\" alt=\"caustiche vray\" width=\"476\" height=\"234\" \/><\/p>\n<p>I hope you liked my simple tutorial about <strong>V-Ray caustics!<\/strong><\/p>\n<p style=\"text-align: center;\">*<\/p>\n<p style=\"text-align: center;\"><span style=\"color: #ff0000;\"><strong>This post has been updated<\/strong><\/span> &gt;\u00c2\u00a0<strong><a href=\"https:\/\/www.cg-blog.com\/index.php\/2011\/12\/27\/vray-caustics-setup-tutorial.htm\">V-Ray Caustics V2<\/a>\u00c2\u00a0!<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>When the light pass through a curved and transparent body (glass, water ..) it result concentrated in some areas. This effect is called Caustics. Learn how to simulate it with V-Ray Caustics.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false},"categories":[58],"tags":[61,22,23],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/posts\/298"}],"collection":[{"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/comments?post=298"}],"version-history":[{"count":0,"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/posts\/298\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/media?parent=298"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/categories?post=298"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/tags?post=298"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}