Collections are a really simple way to group and organise your scene elements in Blender 2.8. This is particularly useful if you have a lot of elements in your scene.
Render layers can be used to render different elements or different groups of elements in your scene separately. For you example you may may have a bunch of objects that make up the background elements of your scene and another object or collection of objects in foreground. In this case you could render the layers of elements separately and if for example you needed to re-render the foreground elements you could do a render of that layer only without having to re-render the background elements. Here is the example Blender file.
Working with Collections in Blender 2.8
Collections are really quite straight forward and to me they are a lot like layer groups in Photoshop. All you need to do to make a collection is:
- Right-click in the outliner and select new.
- Drag your elements in and out of your collections (see demo in video tutorial)
You can also edit the properties of a collection by first selecting the collection and then clicking on the properties tab.
Working with Render Layers in Blender 2.8
To work with render layers in Blender 2.8, firstly if you do simple image render and you will notice in the top right that it has rendered the default ‘View Layer’.
To create a new layer click on the symbol next to the Layer View and then name it. In this example I used the same name for my Background Elements collection, but this is different to the collection itself.
You can click the button to view a list of your layers. In this example (also shown in the video demo), I changed the default ‘View Layer’ to ‘Combined Layers’ and created another layer called ‘Suzanne’.
Now when you have one of these layers selected you can then right click on the collection and enable or disabled it for a layer. In this example I have created a really simple scene with a plane and cube object in the ‘Background Elements’ collection, a collection for the light and camera, and a collection for the ‘Suzanne’ object.
Now you can select a layer from the menu above the outliner and then disable or enable the collections that will be active in that layer.
Once you have setup your layers you will find that if you render and image, your render will include the different layers as separately rendered images.
* Please note, that if you want the layers to include transparent backgrounds enable the Cycles render engine and under Film tick the checkbox for transparent.
You can also adjust the settings of a collection by first selecting it and then selecting the properties tab below. Here you can do things like select whether you want a particular layer to render or not.