Using HDRI backgrounds in Podium Walker with Iray
Podium Walker with Iray Beta includes an option to use HDRI backgrounds to drive image based lighting instead of the SketchUp sky/shadow system.
Using 360° HDRI backgrounds can be very useful for exterior rendering, and also studio lighting scenarios (for product or industrial design rendering), as they help add realistic reflections and subtle, natural tonemapping to your render.
The current Podium Walker beta comes with two HDRI backgrounds installed automatically, which can be accessed in the Background Settings dialog (pictured right).
Click the cloud icon and switch the the sky mode to "texture." The dropdown contains a list of all HDRI backgrounds currently installed.
How to install additional HDRI files
Podium Walker installs HDRI backgrounds in the following directory on windows:
To add additional HDRI skies, simply add them to this folder and they will show up in the dropdown menu as shown right:
We've added a clear morning, a sunrise, and a partly-cloudy afternoon, depicted below. These three images demonstrate the varied reflections and tonal differences you can get with different HDRI backgrounds:
Where to find HDRI Files:
HDRI backgrounds are difficult to create on your own, but there are several vendors who provide both free and commercial HDRI packages that can be downloaded and used with Podium Walker. Check the following suggestions if you're looking for additional HDRI sky backgrounds:
HDRI Skies.com - Large collection of free and commercial HDRI backgrounds. Free with limited resolution, and paid commercial packages at higher resolutions if needed. This is the best option we know of for natural sky/background images with few man-made objects in the scenes.
- sIBL Archive - Smaller library of free HDRI sets for image based lighting with a variety of styles & settings.
- Dosch Design HDRI - High quality premium HDRI sets; mostly paid content.
- HDRI Hub - HDRI aggregator site that links out to a wide variety for both free and paid sky and background options.
A note about Image Based Lighting (IBL):
When using Podium Walker in Texture (HDRI) mode, the HDRI image becomes the primary form of lighting in your renders. The disadvantage here is that you no longer have exact control over where you shadows will fall, the advantage is that lighting, brightness, and shadow angle in your scene will always precisely match your background image.
To control shadow angle to some degree, look for the brightest point in an HDRI image (this will usually be the sun), and rotate your model accordingly.