{"id":1010,"date":"2011-12-07T14:16:18","date_gmt":"2011-12-07T14:16:18","guid":{"rendered":"https:\/\/www.cg-blog.com\/?p=1010"},"modified":"2014-03-16T17:16:09","modified_gmt":"2014-03-16T17:16:09","slug":"dof-vray-faster","status":"publish","type":"post","link":"https:\/\/www.cg-blog.com\/index.php\/2011\/12\/07\/dof-vray-faster.htm","title":{"rendered":"How to render faster Dof in V-Ray with Shade Map"},"content":{"rendered":"

– Click\u00c2\u00a0LIKE<\/strong>\u00c2\u00a0above, if you like this post\u00c2\u00a0\u00c2\u00a0–<\/p>\n

Have you ever rendered with Depth of Field<\/a> effect in V-Ray<\/strong>?<\/p>\n

Render Time increase significantly, especially if you use high subdivs values (in the sampling rollout)\u00c2\u00a0to reducing the graininess. In this case the time increases even more. First of all I wanto to clear that I prefer\u00c2\u00a0\u00c2\u00a0to create such effects in postproduction, but in this post I’ll tell you how to render faster with DOF\u00c2\u00a0directly in the V-Ray.<\/p>\n

Here is a simple Dof example:<\/p>\n

\"\"<\/p>\n

These image takes 7-8 mins without Dof, and the same image takes 19min with Dof and subdivs = 15: time is doubled!<\/strong> In this case the difference is just 10 mins, that might be irrilevant. But what happen if render time increase from 5h to 10h? It’s better to know this trick to go faster with Dof \ud83d\ude09<\/p>\n

It’s a simple trick: we can reduce time calculation with Shademap<\/strong> feature.<\/p>\n

OMG… Ciro!! What hell is shademap???\u00c2\u00a0<\/em><\/p>\n

Shademap is a feature for Stereoscopic images, but we can use it for a trick in 3 steps. Start flaggin “depth of field” in the V-Ray Camera, then:<\/span><\/p>\n

    \n
  1. Put in the scene the object VRayStereoscopic\u00c2\u00a0<\/strong>(create>\u00c2\u00a0helpers>\u00c2\u00a0vray)<\/li>\n
  2. Set\u00c2\u00a0Shademap as “Render\u00c2\u00a0shape\u00c2\u00a0map<\/strong>” and then run a first render<\/li>\n
  3. Set Shademap as “Use Shape map<\/strong>” and run the\u00c2\u00a0final render<\/li>\n<\/ol>\n

    That’s just a summary. Let’s go to see the tutorial step-by-step.<\/p>\n

    .<\/p>\n

    1)<\/strong> Insert\u00c2\u00a0the object\u00c2\u00a0create>\u00c2\u00a0helpers>\u00c2\u00a0VRay>\u00c2\u00a0VRayStereoscopic<\/strong>.\u00c2\u00a0Set eye-distance =\u00c2\u00a00.0\u00c2\u00a0and set “mode” = “Render Shade Map”, then assign a file to store the result.<\/p>\n

    \"\"
    \n( Actually\u00c2\u00a0VRayStereoscopic\u00c2\u00a0<\/strong>is used to create stereoscopic images for\u00c2\u00a03D\u00c2\u00a0glasses,\u00c2\u00a0but for now it’s the only way\u00c2\u00a0to access Shademap.\u00c2\u00a0This feature\u00c2\u00a0will be\u00c2\u00a0opened to the public, but\u00c2\u00a0for now we need this trick.)<\/p>\n

    .<\/p>\n

    2)<\/strong> Run the first render and got an image without Dof in 7mins. Even if I activated Dof, this first image does not calculate it. Don’t worry about \ud83d\ude09<\/p>\n

    \"\"
    \n(I don’t need this first image, it’s just a first step to calculate and store the shademap)<\/p>\n

    .<\/p>\n

    3)<\/strong> Back in\u00c2\u00a0VRayStereoscopic<\/strong> object and change its mode in “Use Shape Map”<\/strong>. In the next render I’ll use the data stored in the previous one!<\/p>\n

    Hit render and get a\u00c2\u00a0render with\u00c2\u00a0DOF\u00c2\u00a0(approximate)\u00c2\u00a0in 2 ’50 “:
    \n\"\"<\/p>\n

    (When you run a stereoscopic render you got 2 different images,\u00c2\u00a0slightly different,\u00c2\u00a0as the distance\u00c2\u00a0deviated\u00c2\u00a0eye\u00c2\u00a0set.\u00c2\u00a0In this\u00c2\u00a0case the output is identical so\u00c2\u00a0stop the\u00c2\u00a0calculation after\u00c2\u00a0the 1st image)<\/p>\n

    HERE THE TOTALS<\/strong>:<\/p>\n