How To: Use Image-Based Lighting

Setting up a scene to be lit completely or partially by an image is very simple but there are a few steps to carry out. This short tutorial shows how to set p this kind of lighting.

1. Add a cyEnvironment object to the scene.

The cyEnvironment object is essential if you want to light a scene with an image. Simply click on it from the Cycles 4D main menu to create one.

2. Create a Background material

For lighting a scene with an image, you can't use an Object or Light material. It has to be a special Background material which you can find in the Cycles 4D material list.

However, you don't normally have to do this because when you create a cyEnvironment object, Cycles4D will automatically create a Background material for you.

3 .Edit the node tree of the Background material

By default the Background material looks like this:

To light the scene, you need to create an Environment Texture node and link it to the Color input of the Background Shader node:

4. Edit the Environment Texture node

There are some changes to make to this node. The most important is to add your HDR image, which you can do in the usual way in the Texture shader link in the right-hand pane of the node editor.

Depending on the HDR you use, you may also need to change the HDR texture projection from Equirectangular to Mirror Ball. This is entirely dependent on the method used to make the HDR image.

You don't need to change anything else.

5. Apply the Background material to the cyEnvironment object

This is normally done for you when creating the cyEnvironment object but if you create a new Background material you will have to do this manually.

At this point the scene will be lit by your image. If all you get is black, or a very dark image, you will need to increase the Strength value in the Background node. This increases the light generated by the image.

That concludes this short tutorial. Note that since the workflow is always the same, it is a simple matter to create a material with everything set up then reload it whenever you want to use image-based lighting. All you need to do then is load the desired HDR image and tweak the Strength value.