What does this mean?

MrSinistar

L2: Junior Member
Feb 5, 2008
82
6
I've noticed that in my map, the console says:

hit surface has no samples
hit surface has no samples
hit surface has no samples
hit surface has no samples
hit surface has no samples
hit surface has no samples
hit surface has no samples
hit surface has no samples
hit surface has no samples
Redownloading all lightmaps

What does that mean?