{"id":540,"date":"2022-12-13T12:03:42","date_gmt":"2022-12-13T17:03:42","guid":{"rendered":"https:\/\/animation.monmouth.edu\/instruct\/?p=540"},"modified":"2022-12-13T12:05:53","modified_gmt":"2022-12-13T17:05:53","slug":"rendering-alpha","status":"publish","type":"post","link":"https:\/\/animation.monmouth.edu\/instruct\/autodesk-maya\/rendering-alpha\/","title":{"rendered":"Rendering with Alpha Channel"},"content":{"rendered":"\n<p>If you are rendering elements you want to composite into a background, you need to render the images with a correct alpha or coverage channel. Here are some tips on how to get that.<\/p>\n\n\n\n<p>Please note that 3D renders almost always have a pre-multiplied alpha channel, meaning the transparent portions of the image are (usually) black and semi transparent portion appear darker in the color channels than fully opaque portions. Photoshop transparency is NOT pre-multiplied. If you composite your images in Photoshop, will get dark edges around your objects. You want to use a composing tool, we usually do our compositing in After Effects.<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full\"><img fetchpriority=\"high\" decoding=\"async\" width=\"480\" height=\"270\" src=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearBase.png\" alt=\"Basic render of a Bear\n\" class=\"wp-image-542\" srcset=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearBase.png 480w, https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearBase-250x141.png 250w\" sizes=\"(max-width: 480px) 100vw, 480px\" \/><figcaption>Here is a basic render of a bear<\/figcaption><\/figure><\/div>\n\n\n\n<h2 class=\"wp-block-heading\">Hiding Objects<\/h2>\n\n\n\n<p>Objects that are in your scene, for instance to cast shadows or reflect light, that should not be seen in the render can be hidden from the camera in the shape node by turning off the <strong>Primary Visibility.<\/strong><\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full\"><img decoding=\"async\" width=\"461\" height=\"278\" src=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/PrimaryViz.png\" alt=\"\" class=\"wp-image-543\" srcset=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/PrimaryViz.png 461w, https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/PrimaryViz-250x151.png 250w\" sizes=\"(max-width: 461px) 100vw, 461px\" \/><figcaption>Turning off Primary Visibility on the Floor<\/figcaption><\/figure><\/div>\n\n\n\n<p>This hides the object from the camera but they will still affect lighting, cast shadows and show up in reflections.<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full\"><img decoding=\"async\" width=\"480\" height=\"270\" src=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearNoFloor.png\" alt=\"Bear rendered without a floor\" class=\"wp-image-545\" srcset=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearNoFloor.png 480w, https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearNoFloor-250x141.png 250w\" sizes=\"(max-width: 480px) 100vw, 480px\" \/><figcaption>Floating Bear<\/figcaption><\/figure><\/div>\n\n\n\n<p>The Alpha channel is still fully white as this scene is lit with a SkyDome (aiSkyDomeLight)<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"568\" height=\"134\" src=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/ArnoldRenderShowAlpha.png\" alt=\"\" class=\"wp-image-544\" srcset=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/ArnoldRenderShowAlpha.png 568w, https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/ArnoldRenderShowAlpha-250x59.png 250w\" sizes=\"(max-width: 568px) 100vw, 568px\" \/><figcaption>Show Alpha Channel in the Arnold Render View<\/figcaption><\/figure><\/div>\n\n\n\n<h2 class=\"wp-block-heading\">Hiding a Sky Dome<\/h2>\n\n\n\n<p>In the shape node of an Sky Dome, you can set the <strong>Visibility<\/strong> for the <strong>Camera<\/strong> to <strong>0 (zero)<\/strong> to hide the Sky Dome from the render<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"465\" height=\"323\" src=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/SkyDomeViz.png\" alt=\"\" class=\"wp-image-546\" srcset=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/SkyDomeViz.png 465w, https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/SkyDomeViz-250x174.png 250w\" sizes=\"(max-width: 465px) 100vw, 465px\" \/><figcaption>Sky Dome Visibility<\/figcaption><\/figure><\/div>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"480\" height=\"270\" src=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearOK.jpg\" alt=\"\" class=\"wp-image-547\" srcset=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearOK.jpg 480w, https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearOK-250x141.jpg 250w\" sizes=\"(max-width: 480px) 100vw, 480px\" \/><figcaption>Just the Bear<\/figcaption><\/figure><\/div>\n\n\n\n<p>Now we are left with only the bear. The above image is a JPG, which does not support alpha channels. Here is a PNG:<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"480\" height=\"270\" src=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearOK.png\" alt=\"\" class=\"wp-image-548\" srcset=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearOK.png 480w, https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearOK-250x141.png 250w\" sizes=\"(max-width: 480px) 100vw, 480px\" \/><figcaption>Just the bear, with alpha channel<\/figcaption><\/figure><\/div>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"531\" height=\"406\" src=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearOKalpha.png\" alt=\"\" class=\"wp-image-549\" srcset=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearOKalpha.png 531w, https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/BearOKalpha-250x191.png 250w\" sizes=\"(max-width: 531px) 100vw, 531px\" \/><figcaption>Arnold Render View showing the Alpha Channel<\/figcaption><\/figure><\/div>\n\n\n\n<h2 class=\"wp-block-heading\">Image Planes<\/h2>\n\n\n\n<p>If you are using image planes on your camera, you need to set their <strong>Display Mode<\/strong> to <strong>None<\/strong> under <strong>Image Plane Attributes<\/strong> in the <strong>ImagePlaneShape<\/strong> to have them not show up in the render<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"455\" height=\"294\" src=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/ImagePlaneViz.png\" alt=\"\" class=\"wp-image-551\" srcset=\"https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/ImagePlaneViz.png 455w, https:\/\/animation.monmouth.edu\/instruct\/wp-content\/uploads\/sites\/3\/2022\/12\/ImagePlaneViz-250x162.png 250w\" sizes=\"(max-width: 455px) 100vw, 455px\" \/><figcaption>Image Plane Visibility<\/figcaption><\/figure><\/div>\n","protected":false},"excerpt":{"rendered":"<p>How to render an Image from Maya with an Alpha channel for compositing<\/p>\n","protected":false},"author":3,"featured_media":549,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[78,3,37],"tags":[45],"class_list":["post-540","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-78","category-autodesk-maya","category-rendering","tag-tips-tricks"],"_links":{"self":[{"href":"https:\/\/animation.monmouth.edu\/instruct\/wp-json\/wp\/v2\/posts\/540","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/animation.monmouth.edu\/instruct\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/animation.monmouth.edu\/instruct\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/animation.monmouth.edu\/instruct\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/animation.monmouth.edu\/instruct\/wp-json\/wp\/v2\/comments?post=540"}],"version-history":[{"count":3,"href":"https:\/\/animation.monmouth.edu\/instruct\/wp-json\/wp\/v2\/posts\/540\/revisions"}],"predecessor-version":[{"id":554,"href":"https:\/\/animation.monmouth.edu\/instruct\/wp-json\/wp\/v2\/posts\/540\/revisions\/554"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/animation.monmouth.edu\/instruct\/wp-json\/wp\/v2\/media\/549"}],"wp:attachment":[{"href":"https:\/\/animation.monmouth.edu\/instruct\/wp-json\/wp\/v2\/media?parent=540"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/animation.monmouth.edu\/instruct\/wp-json\/wp\/v2\/categories?post=540"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/animation.monmouth.edu\/instruct\/wp-json\/wp\/v2\/tags?post=540"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}