ProWalker GPU includes an option to use HDRI backgrounds to drive image based lighting instead of the SketchUp sun/shadow system.

Image based lighting is an easy way to add realistic reflections and subtle, natural tonemapping to your render. HDRI lighting also enables users to test a variety of lighting conditions and tonal variations simply and easily.

Check the "Texture" radio button in the Background Settings dialog to activate HDRI lighting.

Five HDRI backgrounds are installed automatically with ProWalker GPU, which can be accessed from the dropdown menu in the Background Settings dialog. ProWalker GPU users are also entitled to over 40 additional HDRI images, which can be downloaded here (license required)

  Preview the five included HDRI backgrounds here.


How to install additional HDRI files

To install additional HDRI backgrounds for rendering in ProWalker, simply place them into the appropriate folder on Windows:

C:\Users\Username\AppData\Roaming\SketchUp\SketchUp 2017\SketchUp\Plugins\ProWalker\PWApp\Backgrounds

Any .HDR file copied into the backgrounds folder will automatically show up in the dropdown menu as pictured right:

Note: AppData is often hidden by default. Read here if you don't know how to view hidden folders.

These three images demonstrate how easy it is to alter the shadow quality, reflections, and tonality of your render simply by choosing a different HDRI background.


Where to find additional HDR Files:

Licensed ProWalker GPU users are entitled to 40 additional high-resolution HDR backgrounds from HDRI Skies.com. These can be downloaded from the below page—please have your license ready to log-in.

  ProWalker GPU - HDRI Library


HDRI Skies.com offers a large collection of 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.

Other HDRI sources:

  • 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.
  • Peter Gutherie Skies - 360° panoramic high dynamic range (HDR) maps for use in all types of rendering. 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 ProWalker 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.

Unfortunately, at this stage there is no mechanism in place for users to rotate the HDRI 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.