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How to use HDRI Environment in Blender
High dynamic range images (HDRI) are commonly used in 3D visualization. It is an image format (.hdr) that contains from the deepest shadow up to the brightest highlight data. Adding an HDRI environment to a 3D model allows for a detailed and realistic rendering of lighting, reflections and shadows.
Applying an HDRI Environment
There are two ways to add an HDRI Environment to the scene in Blender.
The first method is-
Select the World tab from the Properties Editor panel.
From the Surface dropdown menu, add Background.
In the Color input option, click on the yellow circle button and choose Environment Texture. This will enable you to choose an HDRI image file from your storage.
Now you will see the option open image file. Click on the Open button and locate your HDRI file using the File Browser.
After locating your HDRI image from the File Browser, click on the Open Image button.
Your HDRI Environment should now be lighting the Blender scene. You can see the lighting effects in the viewport Rendered View settings or in your Render outputs.
The second method is-
Go to the Shading tab from the top toolbar.
In the Shader editor, change Object into World.
Now you will find two nodes, one Background node and one World Output Node.
Delete the Background node.
Add an Environment Texture node (you can press Shift A and search it in the search tab or use the Add menu from the toolbar of Shader Editor to search).
Connect the Color output of the Envourment Texture node to the Surface input of the World Output node.
Now you will see the option to open an image file. Click on the Open button and load your HDRI file using the File Browser.
Your HDRI Environment should now be lighting the Blender scene. You can see the lighting effects in the viewport Rendered View settings or in your Render outputs.
Rotating your HDRI
To change the rotation of an HDRI background, go to the Shading tab from the Top Toolbar.
In the shader editor, change Object to World.
Then press Ctrl T and both the Texture coordinate nodes and the Mapping node are automatically added (this works if you are using the Node Wrangler addon). Else you can add these nodes manually by pressing Shift A and searching for Texture Coordinates and Mapping nodes in the search tab or using the Add menu from the toolbar of Shader Editor.
In the Mapping Node under Rotation, you can change the Rotation value in the desired axis to rotate the HDRI Background as per your requirement.
How to Create Shadows Using HDRI Lighting
To create a Shadow using HDRI lighting, add a Plane surface and position it under your model.
Now go to Object properties of the Plane.
Under the Visibility section, enable Shadow Catcher. (Your render engine must be Cycles to see this option).
This will now hide the Plane but project a shadow which makes the HDRI more realistic.
Transparent HDRI Enviorment map
You can hide the environment mao from visibility and still have it emit light.
To do so, go to the Render tab from the Properties Editor panel.
Under the Film, drop-down menu select the Transparent option.
Now the HDRI Background will be hidden from visibility but it will still emit light.
