I was porting a 'simple' scene from .X/PMX format via OBJ+MTL, was unable to recreate the render.

I thought it was something to do with transparency maps, spent a while wrangling alpha channels...

Happens it was partly those, one had 'snuck in', but there was something else going on.

'Blast from Past' time: Used to be you'd fast-sort scene objects by distance, draw them on 'second page' of screen buffer beginning with the furthest, work towards your position, flip page to front when done.

( Unless you had enough colour bits to encode distance into object's hue so they'd draw correctly, even sent 'nearest first' from map-scan. D'uh, sadly the provided RISC-OS 'hooks' did not allow that simple 'if greater than' patch in the 'draw' routine without a complete re-do... )

Plan_B was a really, really clever 'map-crawler' which started at your position and sorta 'felt' its way outwards, growing the pic. Sorta 2½_D ray-tracing with light-source on your head. My nimble code drew LHS of screen okay, snarled RHS. Or was it vice-versa ? I was probably days from solving bug when I went down with really-bad 'Flu. Had 'Post-Viral Blues' per 'Long Covid' for three months, simply could not understand my algorithm, code or notes. Game Over...  

Now I remembered MMD has a quirk / feature that rendering PMX is affected by scene's object / part order, not just distance. Akin to Poser's 'force show back-facing polys', you could force draw-order of things at same nominal distance. So, eg, you could draw water streaming down face of wall, or suppress poke-through on snug clothes...

Is there anything like that in Poser ?? If not, then not...

Note: Query is here because I'm looking for an existing, obscure Poser feature, not for 'wish list'...

On the Parameters window of each object/figure, there's such a "Force show backfacing polygons" but it's for the preview only

At render time, it's correctly handled, whatever this setting is:

Yes, that's a neat feature that I've used to salvage cranky 'ports'. FWIW, the 'visible in ray-tracing' option seems confined to Firefly...

Whatever, MMD seems able to force drawing sequence by position in list. Their PMX models sometimes rely on that, confounding correct export to eg OBJ.

Not a problem, is not near top of to-do list...

( Current 'WTF' is salvaging second of two mega-chunky spacer blocks for replacement of the very big, now-too-rusty security pad-bolts & fixings on 'up-over' garage door. Literally only ± 2 mm margin, these were custom-shaped, 'whittled' to fit !! First un-bolted with difficulty, had mild wet-rot. Duly dried, drilled, glue-bonded, hardware upgraded, re-fitted. Yay !! This second unbolted easily, but has mild wet-rot and severe wood-worm. Oops. Currently back-filling vermin voids with glue. When they set, must drill pattern of holes, glue in reinforcing dowels. When set, do some 'orthogonals', too. What fun... )

As I've written elsewhere, you may use the "Visible in raytracing" option with superfly, too, but you'll need to uncheck "visible in camera" and the "Cast shadow" options as well

Thank you.

Sorry, I only mentioned this due to query on other Rendo forum by artist who needed what I'd call a plane's 'artificial horizon'-- Which you've now resolved...