Preview

Render

Camera position and composition are very much not the same.

This image is with the Aux camera. I have also tried it with Main and the effect is the same, so it's probably not a camera setting. I've tried it with other saved Poser scenes and everything works fine for those, so it's would seem to be something to do with this Poser scene.

Any suggestions? This is driving me crazy trying to get a render of what I want.

WIndows 11, Superfly, Poser 13.2.581

It's the glass surface of cube somehow. I'll figure it out from there. If I remove the enclosing cube, which has a glass texture, the problem disappears completely.

It seems to have something to do with this particular material, Basic Glass in the library.

Hmm. Any suggestions? I know Nothing about Cycles...

Glass does present a challenge in P11 and Superfly, everything depends on what type of glass material you are using.  And yes, there are different types of glass and how they transmit, reflect, and refract light.  Usually, it would help if you increased your pixel and transmission values to overcome the grainy effect from the render, but this will be at the cost of longer render times. You will need to screencap your glass material shader and render settings to determine where to make changes.

I don't understand how a enclosing cube can change the perspective setting of the cam? I mean: in the rendered picture, the crotch area is clearly hidden, even though her head is practically at the same place.

It seems to have something to do with this particular material, Basic Glass in the library.

Hmm. Any suggestions? I know Nothing about Cycles...

The Basic glass in the Poser Library is no good for Superfly, it is from older versions of Poser.  

I don't understand how a enclosing cube can change the perspective setting of the cam? I mean: in the rendered picture, the crotch area is clearly hidden, even though her head is practically at the same place.

Drat and darn. I tried the other glass materials in the library and only Basic Glass (and Simple Glass, but it's identical) gives me the foggy effect that I'd like to keep. And -- they both alter the camera perspective in the same manner, natch.

This is the glass material definition:

I don't see anything that screams, "Shift the camera around".

Ah!!!!!!! I think it's IOR, "Index Of Refraction"!! Gonna go try messing with that. Back in a minure.

That's it. I changed IOR to 1 -- and suddenly the camera perspective Does Not Shift, plus I still have the same foggy effect I had before!

Btw, in the original comparison images, the render was only partially done. Only seconds into it. I just wanted enough to show the camera shift. THe final render was not nearly so rough:

Adjust the roughness value of the GlassBsdf node for a 'frosty' appearance.  IIRC, setting the IOR to 1 has no effect.

Thank you for the tip, hborre. That's useful to know. 

Setting the IOR to 1 got rid of the refraction that was causing the shift between Preview and Render.

But setting the IOR is no glass at all.  Reset your GlasBsdf node Distribution Value to 'GGX' instead of 'Sharp'.

I don't think you are getting the effect you are looking for realistically.  You are treating your cube as one piece of solid glass, like a paperweight.  If you intend to have a figure within a glass chamber, you will need to build a box from thin-scaled flat planes as walls.  That is fairly easy to do in Poser.  But if you want Scatter Volume within the chamber, then you will need the cube with separate material placed into the chamber.

I'm not terribly concerned about it being realistic, although your tips about realism are always valued!

And -- Wow! You were so right about IOR and GGX and all that. Just Wow! That solves the issues AND improves the image.

Incredible. Your imagery knowledge is awesome.

Hey -- somewhere weeks ago you showed how to add a node for adjusting attenuation of a light source. And I cannot find that information. Could you reshow how to do that?

Ah! But for closeups I still need to set IOR to 1, else the refraction shifts the camera too much. But when back away so you can see the edges and corners of the box, it has to be changed back to, well, it started as 1.45.

Check out what happens when IOR is set to 10!

Below is the node arrangement for making an object emit attenuated light with Cycles and PhysicalSurface nodes.

If you have read my posts above, you will understand that the approach you are using is not very conventional because you are treating the cube as a solid piece of glass.  This means that IOR adjustments will have a very different appearance than using single planes as glass.  That is why you are getting refraction distortions with the camera settings.  You would need to build the scene with 'realistic' props to eliminate unusual render behavior and odd-looking images.

I very carefully read everything I see of yours. It's clear that you know tons and tons more than I do about all this and I try to glean every bit of knowledge I can absorb from your posts.

I shall try building a box from scratch. And I look forward to seeing the difference.

And thank you very much for the information about light attenuation. This time I shall see to it I save the information away somewhere.

There. Snapshotted and saved as a jpeg.

I wrote about this years ago. If you have a single layer polygon, then it represents the boundary between air (on the camera side) and glass (on the inside). The shader you made is going to treat the entire interior volume of the shower as a glass box.

As others said, if you're going to use any "simple" glass shader, then the IOR has to control both reflections and refractions and the only way you will avoid the massive refractive distortion is to have TWO parallel surfaces, such that the volume of "glass" is very thin. The combined enter/exit refraction of thin plates of glass is just a tiny shift in the light path. The shift through a glass box towards the interior is not tiny at all but enormous.

The other approach that doesn't require geometry changes is to use a shader that handles reflection and refraction (or transparency) separately. Then you can fake the absence of refraction quite easily.

A good example is here:

https://community.hivewire3d.com/threads/good-glass-material-for-poser.4084/

In case the link doesn't work:

Thank you so much! I will definitely have to try that out!