HDRIs are captured from the ground... so why are we using spherical projection?

The answer is... we shouldn't be! Enter HDRI Dome Projection!

With one button press we instantly get accurate:

1. Ground lighting.
2. Ground reflections.
3. World scale.

Now why is this different than slapping an HDRI on a sphere mesh and flattening the bottom?

Well if you want longer render times, inaccurate object-emission lighting, and extra comp work then there is no difference ;)

HDRI Dome Projection works right from the world shader! No additional render time whatsoever!

How does it work?

Simple.

1. Click 'Create Dome'.
2. Choose any HDRI.
3. Pick your parameters (not mandatory).