lighting in egg

Hi there,

I have a floor which it is bright when lighted from one side, but very dark when lighted from another side. I want it to have the same color no matter how the lighting is turned. Object is exported from blender using yabee.

Picture from one side:
pasteall.org/pic/show.php?id=100495 (bright floor)
Same Lighting, same scene only went around the corner and turned around:
pasteall.org/pic/show.php?id=100496 (dark floor)

The main Problem with that is I am forming a maze and to fit everything i am rotating the parts around. So a hallway looks like that:
pasteall.org/pic/show.php?id=100497

I would really like the floor to have the same color no matter in which direction I go around…

The egg:
ix.io/rjs

Thanks in advance for any help. Would be appreciated!

Solved by wezu, rdb and tobspr in IRC. The normalmap seems to be weird.

This is a problem due to the fact that the scene is not single mesh.

It is necessary to export object as one mesh

Example: