Bear with me... a long explanation but with pictures to illustrate the issue.

I created a scene with a building, trees, and surrounds, and the story I am telling means I am moving the characters around the scene to various locations within it to render an image that will accompany the story text at that particular point.

Rather than move the scenery around the characters, I am obviously moving the characters around the scene, which is how I discovered this (which might have been noticed way back when Poser 7 was current but I wasn't reading the forums here as much back then)...

Anyway... one of my characters I'm using is based on Poser 7's "SydneyG2_Alternate", as it is titled in the Library. (The other is a Sasha-16 V4.)

The story requires the characters moving behind the main building, ending up with their Z position being about -36200mm (I always use millimetres for my scale). When I began to render, I noticed my Sydney character had black scleras. Intrigued, I checked that nothing had been changed in her eye materials by accident.

Nothing had been changed so I zoomed in with the Face Camera and rendered just her suspect eyes. Here is what I saw:

Which looked strange to me because the black part does not correspond to any material zone area.

So, I thought I'd investigate a bit.

First thing I did was remove the glasses, thinking that maybe the lens shader is somehow messing things up. I re-rendered without the glasses and got the same strange blackness. So then I restarted Poser (the latest version of 12, rendering in Superfly) and loaded my character into a blank scene. She came in at 0,0,0 and a render through the Face Camera showed perfectly normal scleras.

Next investigation was to move the character to where she was in the original scene, but minus the other character and scenery. The render? Exactly as the picture above shows (but with different lighting and reflections, of course, because the surroundings are now gone).

I restarted Poser with nothing but an infinite light and the Ground plane, and loaded in a straight-out-of-the-box SydneyG2_Alternate, the figure on which my character is based. This figure has nothing fancy in the eye shaders, and just to be sure, I made everything as simple as possible, using only the texture map going to the Diffuse, and nothing else. In other words, the most basic texturing possible.

A render at 0,0,0 produced nothing unusual, so I moved the untouched, fresh-out-of-the-box Sydney to the location of the other one, and rendered. Yes, the black areas appeared.

So, is it the location? Apparently so.

At z = -32100, the render looks perfectly acceptable:

At z = -32110, something starts happening:

Notice the tiniest beginnings of something dark happening to the right of the iris.

At z = -32113, there is a full ring of black surrounding the iris:

And a few mm further, for z = -32125:

There is no doubt it has grown. So, from -32100 to -32125 some kind of threshold is crossed which makes the sclera develop these dark rings.

Moving the figure further back in the Z direction did not increase the size of the black rings and I couldn't get it to be as widespread as the original character's eyes had (as seen in the first picture in this post), which is mystifying.

But regardless of why the difference exists, there is still something unwanted going on with SydneyG2's eyes. (I also tried the same thing with the non "_Alternate" version and got the same result.)

When I made the head invisible so only the eyeballs are showing, this is the result at -32125:

After that round of investigating, I wondered if the same would happen if I moved the figure forward on the Z axis.

Result? Yes. Once I push the SydneyG2 beyond z = 31886mm, the black banding begins to appear, increasing as I push millimetre by milimetre until it hits a point beyond which it never expands no matter how far the Z value goes up.

The immediate solution is to make sure I never move my Sydney character beyond a certain limit on the Z axis. Which for most circumstances is perfectly fine. But for the scenes I am hoping to render, this solution will result in me moving a lot of props around so that my Sydney character remains inside her usable boundaries.

And really, there shouldn't be any sort of limitation like that when using a character, should there?

Has anyone encountered this before? And... does it happen for other people, too, or is it merely something weird for me?

Wow. That's a case of "Poser is haunted" that I've never seen before LMAO

Afrodite-Ohki posted at 7:29 AM Thu, 16 March 2023 - #4458660

Wow. That's a case of "Poser is haunted" that I've never seen before LMAO

It's weird indeed!

I've played around a little more and found that it also happens when moving Sydney along the X axis. I only tried the negative values to see where the threshold was, and it started to appear a tiny amount at x = -32044,, increasing to full rings beyond that. I didn't bother playing about with positive X values, guessing it will probably be the same.

I also gave SimonG2 a try, and he also exhibited the same symptoms, although his threshold before the black rings appear is different from Sydney's.

Something in the modelling method these two figures used that no other figures have? (I tried Pauline 2 and Jessi at random, and they were flawless at the translations I tried.)

Are you rendering in superfly or firefly?

It looks normal for me with firefly but superfly gets similar results.

My guess is something to do with how the transparency or reflections are being calculated at extreme distances.

It may have to do with whether you're using an environment dome or not. Iirc superfly requires a dome in order to catch light bounces properly. I may be entirely wrong on that tho.

But it's not the model, or it would happen in both render engines.

So something to do with how materials are being calculated is my guess.

AmbientShade posted at 8:49 AM Thu, 16 March 2023 - #4458677

Are you rendering in superfly or firefly?

It looks normal for me with firefly but superfly gets similar results.

My guess is something to do with how the transparency or reflections are being calculated at extreme distances.

It may have to do with whether you're using an environment dome or not. Iirc superfly requires a dome in order to catch light bounces properly. I may be entirely wrong on that tho.

But it's not the model, or it would happen in both render engines.

So something to do with how materials are being calculated is my guess.

Also, I deliberately removed everything except the texture map applied straight to the Diffuse channel, thus ruling out strange reflections and other effects. What you see in all but the first image is nothing except the texture, nothing else. The only transparency is the Cornea material, which I have set to completely invisible.

Everything works fine with other models (even older ones), and everything in the material settings is the same (i.e., nothing fancy, just a texture map applied), so it's not something that applies universally across all models set to those extreme translations. I place, say, a Pauline 2 at an extreme Z translation, remove everything from the materials except for the texture maps, and it renders perfectly. I do precisely the same for Sydney (and Simon, too), and the black rings appear. And only appear on the Sydney and Simon figures. It is definitely not the shaders otherwise it would happen to every figure I've tried and amended to match how Sydney's eyes are set up.

Are you using the alternate Sydney because of the poly count? Just wondering if you tried this with just regular Sydney?

rokket posted at 9:29 AM Thu, 16 March 2023 - #4458682

Are you using the alternate Sydney because of the poly count? Just wondering if you tried this with just regular Sydney?

But I do mention in the original post that I tried the non-Alternate version, too.

Ok sorry missed that part.

I just loaded the model in blender, normals are fine.

The only other guess is that the eye trans geometry is too close to the inner eye geometry and causing a conflict with the transparency. I can't spot anywhere that it actually intersects tho so I don't see why that should really cause a problem.

You could try creating a morph that shrinks the inner eye geometry or enlarges the outer eye geometry slightly and see if that changes anything.

Applying a subdivision level to the eyes might help, but they're already pretty high poly to begin with.

You could experiment with different material settings or you could swap her eyes with another figure's eyes.

>> The only other guess is that the eye trans geometry is too close to the inner eye geometry and causing a conflict with the transparency. I can't spot anywhere that it actually intersects tho so I don't see why that should really cause a problem.

That was my initial guess. 

AmbientShade posted at 9:54 AM Thu, 16 March 2023 - #4458687

You could try creating a morph that shrinks the inner eye geometry or enlarges the outer eye geometry slightly and see if that changes anything.

And report back here with the results.

Well the morph didn't fix anything, and I shrunk it plenty to make sure there was ample space between the two. 

But I can't find any other issues with the geometry that should be causing it, so it really makes no sense. The materials are extremely basic.

On a side note, has Poser's cameras always been so unstable at long distances? Is there a way to adjust that?

My guess would be geometry also.  I've changed the eye shaders to Cycles for Superfly rendering and the same thing occurs.  The Ground area has been completely turned off so there is no influence from that.  Overhauling all the eye textures does nothing and adding an HDRI background does nothing also.  Be aware that the z position is well beyond the P12 construct equalling -1430 inches or -119 feet in comparison to -32,125 mm mentioned in the post.

It gets weirder.

This is what happens to her skin at z -10,000 when she's converted to poser unimesh and a subdiv level of 1:

There is no reason I can think of that the geometry should take on a wrinkling effect just from being relocated in the scene. If it were a geometry issue then it should be happening at 0 0 0 as well but it doesn't.

Is this a Firefly render?

No just a screen cap.

Not seeing it on my system.  Everything perfectly normal.

I found this interesting because I've used Sydney extensively and never had a problem. Apparently, while I've done large scenes,  I've never done them quite that large. I started testing other figures. I chose older ones figuring it might be related to age or some modeling technique of old. I used Jessi, Jessi G2, and Alyson 1. There were no problems with either Jessi, which surprised me since Sydney and Jessi 2 share some geometry iirc. Alyson also had problems with the eyes

SydneyG2 and JessiG2 do share the same body geometry. The face and eyes may be different. I have to check.

Just for fun, I checked a few more figures. Posette, Judy, Pauline, Dawn, La femme, v3, and V4 do not have problems.

Alyson 2, Miki 4, Roxie, and PE do.

Interesting. I'll check to see if I can find any common denominator

It's interesting that we see this happening at extreme distances outside the realm of the construct and not within closer areas of the stage.  Upon closer render examination, it almost appears like an occlusion.