i've made an asteroid by creating a nurbs sphere and then using the sculpt geometry tool to, well, sculpt it into an asteroid. i've also made an asteroid texture in photoshop and then mapped it to the colour of a lambert. when i texture the asteroid with the lambert shader it distorts in some places, it stretches in places i've stretched the asteroid.
is my only option to turn the asteroid into a polygon and use uv mapping because unfortunately i don't seem to be able to get my head around that! please tell me there's an easier option!!!!
Going with polys isn't your only option, but there isn't really an easy and painless one. Applying 2D textures to 3D geometry is not trivial and continues to be something many artists struggle with. Some suggestions (I'm not a texturing guru; these are just vague notions):
1. 'Reverse engineer' your texture by noting where it stretches on the object and trying to paint the opposite properties on the texture in Photoshop in those areas (e.g. if it gets compressed horizontally in one section, paint that section stretched out to compensate).
2. Apply your texture as a 3D projection instead of a regular 2D texture. Each 3D projection type has its own limitations, though. A spherical type will pinch at the top and bottom; a planar type will stretch along certain axes and mirror itself front-and back. Will the camera ever see the back of the object? If not, you might get away with a ball projection.
3. Use procedural textures instead of or in addition to painted ones. These textures don't rely on UV info and so don't stretch or warp.