I was just talking shop with another member, whom mentioned having a Poser .SHM file; in with his .PZZ, and .PMD, but I've never seen this before

This is what the file contains at the beginning:

Tempest Raster Image Format
(C) 2000 - 2002 Pixels
Version *1 1 0

ImageBounds [0.000000 0.000000 255.000000 255.000000]
CompCount 4
CompSize 1
ChunkSize 4
RowBytes 1020
GammaSize 256
Gamma [ 0.000000 0.003922 0.007843 0.011765 0.015686 0.019608 0.023529...*

Could stand for (SH)adow(M)ap and would make sense if you chose to reuse shadowmaps.
That's only a logical conclusion because of the found data in the file. 0 to 255 looks like the standard dimension of a shadowmap (256x256) in Poser. The Gamma data makes then sense too if the file is related to shadows.

Maybe Poser creates these files if you enable this feature and save the scene. It could reuse the shadow maps then if you load the scene again and doesn't require a new calculation of shadows.

It's a shadowmap file, and sometimes they appear in my data directories even when I don't use the option.  Seems to be just something P7 does, although it does appear to delete them when rendering is finished.

Thanks Zarat!

Sounds reasonable.  

I never render shadows, which may explain why I never see them.

:tt1:
Thanks guys!

P5 used to collect them. I remember the large amount of map files we had to delete until CL fix it.