In which file are the render settings stored?
And are the settings from different versions 6 and 7 interchangeable by copying that file?

The exact location seems to vary with Windows versions.  Search your
disk for the folder "RenderPresets" and you'll find the files with a PRP
extension.  They are text files, seem to be pretty much the same thing
as the render info section from the PZ3 with a new header and footer.

Thanks, I found 2 prp files on my pc, but that they were related to poser items.
I  am looking for the place where the saved setting from the firefly save settings menue are stored.

I think the prp files are the presets that you save in the Render Settings window. I think the actual render settings are stored in the pz3. In the case of opening a new document they will come from the "preferredState.pz3". In P6 this file lives at:

[Poser Folder]RuntimeprefspreferredState.pz3

Within the "preferredState.pz3" the render settings are found in the "renderDefaults" section of the file, near the end of the pz3.

Thanks, but maybe my description was not prcise. If I open the firefly renderer settings, I can change settings like "Max bucket size", "Raytraceing",...
and then I can save the changed settings.

I did not find these settings in the files menrtioned above.

Attached Link: http://renderosity.com/mod/forumpro/showthread.php?message_id=3226065&ebot_calc_page#message_3226065

Thank you that was the good link, if found them.