So I splashed out and bought a hair prop today. Test renders of it seemed to be glacially slow, even by poser standards, (over 10 minutes) and modo renders, though quick (under 12 seconds) show some render artifacts.

On close examination I find that the geometry is unusual in the sense that the entire mesh is duplicated, with the copy having flipped normals, so there are polys (all tri's actually) facing out and duplicates facing in. I imagine this was intentional (because the 2 material zones are named 'outside' and 'inside'), though the reason for it escapes me.

But then I see that about 50 hair strips in the mesh are duplicated again, so in these there are now 4 polys in the same space, 2 facing in and 2 facing out. This can only have been accidental. Clearly firefly didn't like them, because deleting all the duplicates drops the render time to 2 minutes in Poser and 5 seconds in modo.

So here's the thing: Rendo Marketplace testers didn't pick this up because they didn't even glance at the geometry. How do I know this? Because this hair prop is all embedded geometry in the hr2 file, there's no .obj file. 

I thought embedded geometry was a big no-no, so I looked again at the Marketplace Submission Quality standards and Guidelines, and lo, it is written:

"Poser files (.cr2s, pz3s, etc) should never include mesh data (embedded geometry/object). Objects should be stored in the geometry folder, and should be pointed to with the proper path within the file."

"Should"? That sounds like its optional, recommended, but not mandatory.

Well, fancy that!

PS: I'll tell the vendor about this mesh issue and if he/she doesn't issue an updated version I'll post the name of the prop here so people who are experiencing slow renders with it can fix it themselves.

Should is recommended, Must is mandatory

Quote - Should is recommended, Must is mandatory

That's how I would read it, but elsewhere in the submission guidelines, under 'product files' it says: "All files required to make the product functional should be included." I would have thought 'must be included' would be more appropriate, because there's no way that can be optional.

Content Paradise is known for embedded geometry and even putting obj and image files in the prop folder. There is no problem in doing so, its just nonstandard.

I believe the testers job is to see some standards are met, and that the thing works as advertised. I dont think they look at any of the code.

The duplicate geometry if slightly offset allows for texturing that is visible in preview rather than just getting the back side of a polygon.

Quote - The duplicate geometry if slightly offset allows for texturing that is visible in preview rather than just getting the back side of a polygon.

In this case it's not helping in preview, where the main part of the hairdo looks like it's inside-out, probably because there's no offset between the polys.

The doubled-up transparent polys seem to really punish firefly, particularly with shadows on. There seems to be some z-fighting between the layers of polys too, which can't be helping calculation times.