Until now I had never used the subdivide option in Reality/LuxRender, but now I've seen how it can make or break an image!

 

 Of course the difference can only be seen in the full-sized version:

http://www.renderosity.com/mod/gallery/media/folder_247/file_2463868.jpg

I had to apply quite a bit of JPEG-compression to comply with Rendo's 512 kiloByte rule, but the difference is obvious enough I think.

Didn't expect the poke-through though.

The difference in colour must be related to the number of samples per pixel, I broke off the non-subdivided render when I saw what mess it was turning into.

Lessons learned! (again)

Cheers!

Erik