Surface Normal
If we were standing on the surface of a plane, the normal points straight up:
Ground Flat on X-Axis
If the ground is flat along the x-axis, then the y-axis becomes the surface normal, because a flat ground along the x-axis points straight up the y-axis:plane { y, 0
pigment { Blue }
}
Adjust the height of the ground
Sink the ground 20 metres below sea level, and give it a different colour:plane { y, -20
pigment { checker Red, Blue }
}
Challenges
- make a ground and a sky (so use 2 planes), and adjust the camera so it looks at both meeting in the horizon:
