Have you seen the amazing ability Photo Lab has to quickly light a space with just an image as a background? No? Well, check this out!
Here's a great example of the light changing in two renderings of the exact same room just from changing the background image:
Nothing was changed about this scene - not the light sources, materials, anything - besides the background image in Photo Lab - but the whole space has a different temperature and level of brightness emitted from the image in the window.
It's really easy to use this feature in Simple Mode too, but there are some additional features in the Advanced Mode.
Using image based light in Advanced mode
- In the Lighting & Shadows section in the Advanced Mode, select Image based light from the drop-down menu.
- Click on the thumbnail to open an array of high-quality images you can choose for your background. See below for more info.
- Drag the slider bar to rotate the image on the X-axis. That way you can see a different part of the image outside of the window.
If it is hard to see what part of the image is in the background, just click Preview at the bottom of the Photograph Setup area:
This will show you a small snippet in the Render Tasks dialog of what the result will be like out of the window!
- The Use image as background box needs to be checked if you want the image to actually show outside. If it is unchecked, the image will affect the lighting but will not be visible. Photo Lab will still read the brightness and temperature from the image to determine how lighting should come into the space, but the background will be determined in the Background section. See below for more information.
Choosing an image to light your space
In Step 2 above, you need to choose an image that you would like to use for the background. Here are the steps to do so:
- Click the preview of the current selection. This will expand a wide array of High Dynamic Range (HDR) images to select.
- Click on the image you want to use. By default, images are stored in the cloud, so when you click an image it will first need to download. Give this step a second, then you should see a grey progress bar at the bottom of the image's preview to show that it is working.
To have all the images available, click Download All at the top. Downloaded files will remain on your computer so you do not need to re-download them each time you open CET.
- Once an image is downloaded, you will see the icon of a hard drive. (You will not need to download them again.) After clicking it again, it will load in the preview and will show in the background of your rendering if you have Use image as background checked.
If you do not check the box Use image as background in the Lighting and Shadows section, then you may want to set another background instead. You can choose a solid color, a realistic-looking sky, or a different image from the one generating your lighting. All the details about adding your background can be found in this article.
You can bring in your own images to use as a background, as you will read in the article linked above, and you can even use them for your imaged based lighting. However, to use them for lighting, you will need to find a High Dynamic Range (HDR) image in the EXR file format.
A great resource for finding EXR's is Poly Haven. All the images on this site are free, but always make sure that it is available for commercial use. As of the initial publishing of this article, all images on this site have a CC0 license, meaning it is free for use in commercial settings, but always double-check before using any. You can find the license information under the Download section:
If you retrieve an HDR image from any other source, check the license! Some images must be purchased for commercial use, and some cannot be used at all.
Any non-HDR images can still be shown in the background of your renderings but cannot generate light, so you would need to add your own light sources.