Decided to do a comparative render using the three material methods for transmapped hair, same lights, same pose, no changes except how the hair material is setup. So you can see what your mileage might be rendering this sort of organic matter, I have a P4, 2.8 gHz Intel box with a gig of RAM, and a NVidia 6600 GT graphics card. Nothing flash.

For lights, I've got two omni lights with only one with soft shadows enabled, neither with caustics enabled. Background is the KT sunset sky, which to my understanding also adds a type of light to the scene.

On a side note, I do see some sort of strange artifact on the back of the head at the hairline and another showing just slightly on Vicky's cheek - not sure what they are... but they are showing up in all of the renders. The models have been imported scaled up x 1.8...

=========================================================
The hair material settings for the first render are as follows (developed by Notareal and endorsed by most of the other wizards on the KT forum):
[Layered material]
  Weighting
.....Weight#0 Transmap bitmap
.....Weight#1 Transmap bitmap (Bitmap options: Tick Inverted)
...[Matte/Phong#0]
   Reflectance
.....Diffuse: Texture bitmap
...[Matte/Phong#1]
   Transmittance
.....refraction: Colour white
This is the result:
www.tightbytes.com/images/Poser/Kerkythea/Short_Bob16.jpg
Render time: 40min, 30sec

=========================================================
For the next render, I used obm890's settings:
[Matte/Phong]
   Reflectance
.....Diffuse: Texture bitmap
   Transmittance
.....refraction: Transmap bitmap (Bitmap options: Tick Inverted)

www.tightbytes.com/images/Poser/Kerkythea/Short_Bob17.jpg
Render time: 27min, 58sec

=========================================================
For the next render, I used Kim Frederik's settings (a KT guru):
[Matte/Phong]
   Reflectance
.....Diffuse: Texture bitmap
  
.....refraction: Transmap bitmap (Bitmap options: Tick Inverted)

www.tightbytes.com/images/Poser/Kerkythea/Short_Bob18.jpg
Render time: 4min, 40sec

On this last one, there's no question that detail suffers for the masking technique on close-ups. For open landscape scenes or architectural settings where the focus is the building, not the person, the last setting delivers a decent-looking render:

www.tightbytes.com/images/Poser/Kerkythea/Short_Bob19.jpg
Render time: 28sec

In any event, this is one HOT renderer of which I haven't even scratched the surface.

I get the artifacts, too. I was concerned that I was not exporting correctly or something.

Here's some more data.

I was using Kerky 2.05 - saw artifacts.

Upgraded to kerky 2.08 - artifacts disappeared in raytracing, but all other render methods showed them.

Upgrade to Kerky 2.09 - artifacts are back all the time.

I was going to post about this at K forums, but I feel like I don't know what I'm doing yet. So I didn't. Plus I didn't want my first post there to be a bitch post complaining of a bug. Worse, what if its not a bug in Kerky, but a bug in Poser export!?!

Quote - > Quote - I looked for a dokumentation about the XML-format K uses. It should be possible to write some kind of exporter, at least for geometries, lights and camera. You will have to fix the materials, and probably the lighting as well, but it would be a starting point.

I have played with the renderer on the last weekend, and I liked the results. Nothing I would care to publish here, but that's fine considering that I did not spend that much time for it.

So, if I get the dokumentation and find some people here which would do some testing, I would give it a try. I'm not that fluently in Poser Python, but I do have some programming experience and I'm willing to try it.

If you want to, you can use my Poser->Yafray python script as a starting point:
http://www.keindesign.de/stefan/poser/scripts/poser2yafray.py

Getting basic camera, light and geometry support shouldn't be very hard. Translating material and lights properly can be more tricky, but odds are most users want to use K-specific light and material setups anyway so you won't need to get that 100% right.

Do you know if it supports any other primitives than triangle meshes? If it supports cylinders, translating dynamic hair will be easy, if it doesn't you'll have to come up with a scheme to turn hair curves into polygon meshes without having the polycount explode.

Thank you for the offer. I already looked in your exporter when I played around with yafray some time ago, it's good to have a similar script as a guideline.

Camera, geometry and light shouldn't be much of a problem, true. Hair will need some work, Kerkythea only knows triangles, as far as I can see. Since it's no REYES style renderer, high order surfaces probably won't have real advantages anyway. So i just will have to replace the cylinders with cylinder shaped tri-based meshes, and hope for the best.

I would like to include at least some basic material conversion. Transfering node-based shaders probably will not work, but maybe I can do some smart replacements - I will look into that when it's time.

The lighting should be done in Kerythea, that's right, but I want to give a starting point to users, which have working lights in Poser, mostly because I don't think it will be much work. But just rendering in Kerkythea, without changing the materials and lighting system isn't going to produce better renders - for me the point in using K is the better lighting system.

I will see how far I get, and will send you a mail if I need help.

Quote -
If you want to, you can use my Poser->Yafray python script as a starting point:

There's also a SketchUp -> Kerky script (ruby) which might be of use as reference. It's probably available on the kerky site. It exports geometry, textures, light and camera positions and sets up a physical sky, sun and some good render settings.

Quote - I get the artifacts, too. I was concerned that I was not exporting correctly or something.

Here's some more data.

I was using Kerky 2.05 - saw artifacts.

Upgraded to kerky 2.08 - artifacts disappeared in raytracing, but all other render methods showed them.

Upgrade to Kerky 2.09 - artifacts are back all the time...

When you say artifacts, I'm assuming you mean in the hair. Do you get the artifacts if you set your hair material to the first setting mentioned above, the one with the Layered Material?
I actually - after a fair bit of frustration - created a new figure (squeaky-clean, not a save-as of 7 iterations) added the hair and exported to obj. Only then did I get the results outlined above, so your point of a dodgy export from Poser is not one to ignore.

Also, size matters - I import my Vicky obj file x 1.8 - not sure where I got that number from, but she look pretty-right, based on the squares she's standing on.

Quote - > Quote -

If you want to, you can use my Poser->Yafray python script as a starting point:

There's also a SketchUp -> Kerky script (ruby) which might be of use as reference. It's probably available on the kerky site. It exports geometry, textures, light and camera positions and sets up a physical sky, sun and some good render settings.

I will have a look at that too. Kerky don't seem to have any documentation about the file format, so I will have to analyze that anyway. The SketchUp script will help there, I suppose.

After studying the material system a bit more on my own, I independently came to understand how to configure it properly.

Basically what we're doing now is to define a hair material and an air material. We use the transmap to decide which points are air and which points are hair. We are no longer thinking in terms of transparent hair or opaque hair. That is the old way of doing things. The new way is to actually make the geometry behave like air wherever we want it to.

I see the artifacts with that shader setup. I also see them with any other setup. In fact, I see them with the hair configured to produce just a solid ambient color without using any shader interaction with light and shadow.

Here is the hair - just the hair - loaded and scaled properly into Kerky. We're looking at the back of the hair.

Yet I am getting black. There is some bug here where certain polygons do not get rendered properly. It isn't calling the shader at all.

Correction to what I said earlier - I re-installed 2.0.8 - it does the artifacts too in raytracing.

I think the one time I didn't see them was some kind of oddity.

Quote - Kerky don't seem to have any documentation about the file format, so I will have to analyze that anyway. The SketchUp script will help there, I suppose.

I'm sure if you ask on the kerky forum you'll get whatever info you need. The lack of documentation is most likely because of the small scale of the kerky operation, until recently it was just Giannis on his own (and in his free time) with a handful of testers. I remember Giannis saying once that if he had to write a manual he'd have to stop developing the code. Of course the users agreed that he should keep working on updates.

I believe that more recently other volunteers have joined him to develop particular aspects of the application and things like documentation.  I'm sure there are guys there who know enough about the file format to fill you in.

I have already asked there. The creator of the wings plugin told me that there is no documentation about the file format and that he analysed saved xml files to get the informations he needed. I will have to do it for myself as it seems.

I think there is a bug.

I applied a shader that is just ambient red, or air, based on the layered material transmap approach.

I imported the original hair OBJ. I did not export first from Poser. This is the actual obj file from Kozaburo in the geometries folder.

When you import this obj, the individual pieces come in separately, so you can move them around.

I have taken apart the left side of the hair (we're looking forward from behind.)

As you can see, the individual pieces each render perfectly against the sky.

But the assembled pieces on the right half are producing artifacts.

Before I took it all apart, there were the same artifacts on both sides. I found that I was able to change the artifacts just by moving pieces around slightly.

I was also able to get the artifacts even when I made some of the overlapping pieces 100% air material, instead of the layered mixture.

I was also able to create MORE artifacts by surrounding the whole hair with an air sphere. What I mean is I made a sphere, and attached the air material (100% refraction, IOR=1).

I still don't know precisely how to make it happen. I'm trying to find some combination of overlapping polygons.

This sort of thing usually is the result of not setting enough ray-trace bounces to pass through all the polygons. You eventually run out and get just blackness. But I increased the bounces to 25 and still got the artifacts.

Whenever I'm learning to work with new software, I often find that I think I'm doing something and then I find that is not what I did.

Look at this - no artifacts.

I increased the Max Ray Tracing Depth to 25 and the artifacts are gone.

I think I know what happened. I set the max depth before, and it got slower, so I switched to 2 threads instead of 1 thread, hoping it would go faster. What I didn't realize is that the raytracing parameters for single thread are completely separate from the parameters for 2-thread.

Apparently, when I set the depth = 25, I wasn't actually using 25 because I switched to 2-thread immediately after changing the depth.

Duh.

So - try increasing the depth and see if the artifacts go away for you.

I reloaded the fully assembled hair and the artifacts are back.

I increased depth to 100, which is MORE than enough to reach all parts of the hair. Still does this.

It changes with viewing angle, too. Dang it.

I give up.

i've been interested in other renderers since i noticed that you can't show skin at all realistically without GI, because skin colors itself and makes inner areas more red.  and just in general kind of hitting a limit with lots of faking effects.  i've been looking at Kerkythea specifically for a while, though i haven't tried it at all (too much to do with just Poser and even a bit of Blender).  i could have sworn i had no problem with Yafray and displacement, but i could be wrong.  

one thing that led me to Kerkythea was the flexibility to do unbiased renders.  i've never, ever seen anything like the renders posted in the Indigo renderer's gallery, so i'm definitely interested.  that said, Kerkythea can do regular biased renders (GI, AO, etc.) and with Echo seems to have enough of an interface to make coming from Poser easier.  i'd be very interested in an exporter, especially if it automatically scaled Poser figures up from the tiny size they are originally.  i know i have to scale up by 10 to get a decent size in Blender, and since i've also seen how inaccurate eyes are in Poser due to their scale, i'm guessing it would matter in Kerkythea as well.

is everybody using the "Classic Ray Tracing" renderer?  or are you trying any of the other options?  i know MLT in Indigo looks amazing, but i also know it can take a very long time.  that said, since MLT renders refine over time instead of render more of the image, and since most of my time is taken up in test renders, i'm still interested in trying it some day.

Quote - Supported Rendering Techniques
    - Classic Ray Tracing
    - Path Tracing (Kajiya)
    - Bidirectional Path Tracing (Veach & Guibas)
    - Metropolis Light Transport (Kelemen, Kalos et al.) on top of Path & Bidirectional Path Tracing
    - Photon Mapping (Jensen) (mesh maps, photon maps, final gathering, irradiance caching, caustics)
    - Diffuse Interreflection (Ward)

Quote - Try Vue, instead ;)
http://www.silverblades-suitcase.com/wildspace/characters1realism.jpg

I agree.  I'd take a gander at Modo, too.  If it's within budget.

Quote - Yes - hair artifacts.

After studying the material system a bit more on my own, I independently came to understand how to configure it properly.

Basically what we're doing now is to define a hair material and an air material. We use the transmap to decide which points are air and which points are hair. We are no longer thinking in terms of transparent hair or opaque hair. That is the old way of doing things. The new way is to actually make the geometry behave like air wherever we want it to.

I see the artifacts with that shader setup. I also see them with any other setup. In fact, I see them with the hair configured to produce just a solid ambient color without using any shader interaction with light and shadow.

Here is the hair - just the hair - loaded and scaled properly into Kerky. We're looking at the back of the hair.

I'm not sure this is the answer to this issue, but when I mentioned the fact that I had artifacts, one the gurus at the Kerkythea forum suggested the following:
**The artifact on the back is probably because of too low tracing depth. You would need to "apply" the render presetting , then "cancel" and then increase tracing depth in the render window. The other artifact could be because of Brightness Threshold: lower this value to 0.001 or 0.000. After these changes , render again but this time with "custom" settings.
**

Well I did try depth of 100 as I said above.

The Brightness Threshold is something new to me. I think it means don't send another ray out if it is going to be multiplied by a factor that is lower than this number. However, I doubt it applies here, because the brightness in this case of the errent ray is 100% or 1, well above the threshold.

Still I'll try it, but not today - gotta go off to more consulting.

Quote - Well I did try depth of 100 as I said above.

The Brightness Threshold is something new to me. I think it means don't send another ray out if it is going to be multiplied by a factor that is lower than this number. However, I doubt it applies here, because the brightness in this case of the errant ray is 100% or 1, well above the threshold.

Still I'll try it, but not today - gotta go off to more consulting.

Look, mate, shootin' in the dark, here. You know heaps more'n I do about all this. I just told you what HE said. Colour me Total Newbie. I sense I can learn a lot from you. Hope your consulting went well....