I posted about this issue two days ago and apparently it's something that Poser just does, but I am having a terrible time with it. Many items which use mesh in their production of an object (I use the layman's definition of that word here) give me tons of grief because of the "stitches" that show up in them. I noticed this first with a figure using a terrain morph and then started seeing it all over the place - Terradome's terrains, and now the Cyclorama environments - I'm attaching a crop of the background of one of the Fairytale Story planes:

This kind of thing ruins the render, obviously. So far I have not been able to find a render setting that gets rid of it. This one was done using the automatic settings with everything turned to the max ("Final") and I also had Smooth Polys, Remove Backfacing Polys, and Use Displacement Maps checked, for what it's worth. I thought if I set everything up high maybe the problem would go away, but no such luck.

Can someone suggest a way to avoid this? Surely it's possible or these people couldn't advertise backdrop software such as this - I know it works for somebody but I can't figure out how. I'm using Poser 8, with the latest upgrade from Smith Micro installed.

normals forward?

and also maybe turn texture filtering off

Ahahahahya. I post the same answer twice in the same day. I also point out to all your "guessers" that I've told about this many many times.

SOMEBODY PAY ATTENTION THIS TIME.

Shadow Min Bias on raytraced shadows - raise it.

also did you render it at the highest setting?

I have found the same thing, I turned off cast shadows for the background and it went away, dont know why much about rendering etc, but any insight into what causes this would certainly be of interest.

oop,s late post.

Quote - Ahahahahya. I post the same answer twice in the same day. I also point out to all your "guessers" that I've told about this many many times.

SOMEBODY PAY ATTENTION THIS TIME.

Shadow Min Bias on raytraced shadows - raise it.

you'll probably have to keep repeating it, LOL, attention span and all.

Benboom,

What's the minimum shading rate set to?   Bigger ain't always better - at least in poser terms.  You say you've cranked everyting to the max.   bring the minimum shading down to under 25 and see if that helps.  Errr and don't worry about the backfacing polys either - unles your PC is something out of the arc.  Leave this box unchecked unless your render times are really slow cos you can get weird stuff happening otherwise.  I'm no expert but I hope this wil help  - if it doesn't there are people who really understand who will be able give you a hand..

Great - boggers comes and says the opposite.

I already answered Benboom in this thread 11 hours ago.

http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2794751

Quote - Benboom,

What's the minimum shading rate set to?   Bigger ain't always better - at least in poser terms.  You say you've cranked everyting to the max.   bring the minimum shading down to under 25 and see if that helps.  Errr and don't worry about the backfacing polys either - unles your PC is something out of the arc.  Leave this box unchecked unless your render times are really slow cos you can get weird stuff happening otherwise.  I'm no expert but I hope this wil help  - if it doesn't there are people who really understand who will be able give you a hand..

You mean minimum shading rate down to under .25, don't you. 25 is wildly different than .25. Nobody ever uses min shading rate in the neighborhood of 25.

Anway this has nothing to do with it and you're just going to extend his render times for no reason.

Oooops - Bagginsbill has spoken and he is the cleverset of all - I am very very probably wrong = Do as he says and I'm sure it will solve the problem.   - he is one 'of the people who really understand' of whom I spoke. 

Quote -

I already answered Benboom in this thread 11 hours ago.

http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2794751

That's great, but the Forum never notified me that there was a new reply to my post; it did notify me that there ere replies to this one, which is only a couple of hours old. So I feel a little beat up on here. I do check the forums, but NOBODY can read every post, nobody.

Sorry Bb - of course I meant .25.   I was only trying to explain that a really high  min shading rate is not what you want.  I was only trying to help, in the absence of greater knowlege such as yours,  If I had realised you had already posted  a reply until after I had posted mine I would not have bothered.   There seems to be a major time lag in what is live in the US and the UK, so please make allowances.

Quote - Ahahahahya. I post the same answer twice in the same day. I also point out to all your "guessers" that I've told about this many many times.

SOMEBODY PAY ATTENTION THIS TIME.

Shadow Min Bias on raytraced shadows - raise it.

I appreciate the attempt to help. I checked the Shadow Min Bias, and it was set at .8. I changed it to 2.0 on all four lights with no change. I set it to 5.0 and still no change. 15.0 - no change. Finally, I set it to 40, which is as high as it will go. Zip. So I don't think this is the right answer.

Quote - I have found the same thing, I turned off cast shadows for the background and it went away, dont know why much about rendering etc, but any insight into what causes this would certainly be of interest.

Alas, I just checked and the background already has Cast Shadows turned off.

Quote - also did you render it at the highest setting?

I used the Auto settings, with the slider all the way to the right to "Final", then I also ticked the three boxes I mentioned in my first post.

Quote - normals forward?

I just tried that to no effect, and the same result with the texture filtering off.

two rhings you could try.

1. Set your render setting to the one just before raytracing. Render without raytracing and see what happens.

2. Switch to wireframe display and see if those defects are lining up with an edge in the mesh.

3. will show if its a raytrace issue.

The problem is created by enabling displacement and smooth polys. By turning those on, you increase the problem. Turn off smooth polygons on that terrain or cyclorama. Smoothed polygons are essentially a form of displacement.

As to whether or not min shading rate fixes the problem, I hope you understand that when people think they do something but they dont' actually do it, I chase my tail.

You need to show screen shots of parameters and properties of every light you have. Or - save the scene without any props or figures (so as to avoid copyright problems) and upload the scene file here so I can see your lights.

To upload a scene file it must have a filename extension of .txt or .doc. Add this to the end of the file name - on top of the existing .pz3 - so save as something.pz3.txt and attach to a post. Then we can look at your settings.

Note - my wife returns home in 15 minutes, and it's Valentine's Day, which creates certain obligations. Much as I enjoy helping people with rendering problems, I may not get to it this evening.

Too bad when you posted again, you didn't notice that your previous post had suggestions. Might have fixed this already instead of you spinning your wheels.

Quote - two rhings you could try.

1. Set your render setting to the one just before raytracing. Render without raytracing and see what happens.

2. Switch to wireframe display and see if those defects are lining up with an edge in the mesh.

3. will show if its a raytrace issue.

Ah, now we are getting somewhere! I set it to the level below Raytracing as you suggested and the render has no artifacts. And the "stitches" are exactly where the wireframe display's grid is, although the entire wireframe is not stitched, as you can see in the photo. I don't understand the implications of this, however; they seem kind of dire.

Thank you for helping.

Quote -
Too bad when you posted again, you didn't notice that your previous post had suggestions. Might have fixed this already instead of you spinning your wheels.

Yes, it is too bad. However, you said "Increase your ray bias (shadow min bias) on the light" and that had no effect on the stitches. You also said "You're using displacement and the ray-tracer part of Poser isn't aware of displacement. Thus, the displaced copies of those polygons cast a shadow on their own un-displaced copies." No joy there. 

However, your suggestion to turn off the Smooth Polygons on the Cyc seems to work! With the Render Settings at "Final" again but the Smooth Polygons box unchecked on the Cyc the render exhibits no artifacts - hurray! I'm sorry if you feel like you're dealing with the village idiot; I'm used to POV-Ray and have little experience with Poser. The two have little in common.

I will keep my fingers crossed that the Smooth Polygons uncheck trick will continue to work as I try some of the older scenes I have had problems with.

Thanks to all of you who responded!

Here is RDNA microcosm with smooth polygons off, and shadow min bias .1. Looks fine.

This is rendered with only one infinite light.

Argue with me if you want, but I seem to know how this works and what to do, and you do not.

Show me your settings. Don't tell you what you think you did.

The reason I'm not happy with the solution of disabling smooth polygons is because then your figures will look chunky, if you show them up close. I prefer to use polygon smoothing, and deal with its ramifications.

If you're not going to show anything up close, then turning off polygon smoothing is a fine solution.

But you should understand all your options, because you'll get in another situation where you really don't want to disable polygon smoothing

Bagginsbill, you are talking about the settings for at least six different renders at this point. I wouldn't have the faintest idea which one to send! I'm sorry you feel like I'm arguing with you; that's not my intention. 

Edit: ah, I see what is going on - we are posting at the same time, with each of us one post behind the uther as a result. I understand your last post, which was made AFTER this one; you are right, I do need to understand the difference between the two methods because I can see how there would be situations where the one that just worked for me would also mess things up. In fact, that's why I had the "smooth polys" enabled in the Render Settings - I had already had problems with some figures rendering in a pointy fashion and figured out that I could fix it by doing that.

I hope we aren't cross-posting again, so I will just leave it with that for now. Enjoy your Valentines Day!

Quote - But you should understand all your options, because you'll get in another situation where you really don't want to disable polygon smoothing - bb

so what's the downside of "shadow min bias at 3 inches" ? won't that make stuff look like they are floating cos the shadows are detached too far?

In what order does Poser execute the “Smooth polygons” setting? If I tick “Smooth polygons” in the “Render Settings” menu, does unchecking it on the “Properties” menu for an item override the render settings? Or is it the other way around? If I uncheck the “Smooth polygons” setting in the “Render Settings” menu, does ticking “Smooth polygons” in the “Properties” menu override the render setting?

Also, while it is obvious what a “Shadow Min Bias:” of 3.0 inches does to TerraDome or Cyclorama, as AprilYSH asks, what does it do to the smoothing/shadows of a figure like Alyson or Victoria 4.2? One might easily have a background object like Cyclorama and a forground and close-up object like V4.

I observe that “Shadow Min Bias:” setting seems to be thankfully unrelated to the “Display Units” setting in the “Preferences” menu.

lmk

Smooth polygons in the render settings is the global setting (i.e. Smoothing on/off for the entire scene), the one in the object properties a local setting (i.e. Smoothing on/off per object).

If you disable Smooth Polys on the object properties then even if the global setting is enabled that object will not smooth.
But it doesn't work the other way around - If Smooth Polys in the render dialogue isn't ticked then no smoothing will occur in the scene, regardless of whether the option is ticked in object properties.

You might also want to be aware that even with smoothing enabled, the cast shadow remains that of the unsmoothed object (i.e. faceted - you see it clearly if the object is low poly with smoothing enabled and no shadow blur is used on a RT light). This possibly also adds to potential artifacts related to ray bias.

Something I'm unsure of is whether there is a bias at work with IDL as with AO (I'd assume there is but perhaps not). If so, it'd be useful to have some control over this.
And on the question of raising shadow bias when smoothing is used and how it might affect different objects/figures in a scene, perhaps it might be useful to have control over bias on a per object level as well as per light. I'm not entirely sure whether this even makes sense, let alone if it's possible, but there have certainly been times for me when it seems as if it would be.

I had no idea this issue was so complex and also so abstruse! Surely it must pop up all the time - every time somebody buys one of these products like the cycloramas or Alien World (my first encounter with the problem) and then tries to render it with Ray Tracing turned on. Most Poser users do not have the expertise of the people on this board; do they just give up? Do they, maybe, find this board and ask the question I asked, thus irritating those who have seen it all before? If this is the case then perhaps there should be a sticky thread with a definitive answer in it.

I haven't done it for a while on this subject, but a forum search (keywords - 'Raytrace Shadow artifacts' etc) would usually throw something up.
The problem tends to change slightly as versions change - when AO was introduced there were a whole new swathe of problems. The core issue of shadow bias is common to most 3d apps though, from what I know.
3d just is a tricky beast, even using the simplest of features.

Thank you carodan. I have it straight now.

Seeing that we can have an object by object, control over smoothing, it becomes less of a problem. I have been rendering without smoothing for a while to avoid this artifact. I just rendered a scene in TerraDome that is very complex, with smoothing enabled. It did not create the artifact in the TerraDome textures, but it did cause some distortion in some of the trees. The figures however benefitted from the smoothing. I can turn it off on those objects that look better without it, and get the benefits of smoothing for those objects that need it.

Thanks again.

lmk

Hello,
if "smooth polygons" causes issues, it's typically a problem of the mesh.
For sharp edges, the facets should link to separate vertices (even if they have the same
coordinates), to model a surface, there should be just one vertex.

Usually that problem can be fixed by exporting the object from the modeller with
certain options set / unset. (For blender: Use the object modifier "Edge Split", and check
the option "use modifiers" in the .obj export. If the default selection of "sharp edges" does
not work for you, you can set them explicitly (in blender))

Best regards,
   Michael