Coag rock help

[IISKETCHII]

I recently re-skinned thoze large rocks scattered throught coag...and they look great and all, but one problem

when viewed from a distance, or a cirtain angle, they become completly black (this happens more so when i split screen-with another player, then when i play by myself)

i tried to find awnsers to this and i cam across something call LOD?

im just trying to find out how the level of detail affects these skins and what can be done to correct it

[Reaper Man]

i think it may be something to do with the mipmaps on your bitmap. as in...there are none. mipmaps are like LODs for textures

[citruspers]

i thought it had to do with bump maps?