I need some refraction help in P6. I can't seem to get it to look good. Here's a carafe using the poser default refraction settings (tweaked slightly, and after trying all sorts of other settings). The carafe has a 'glass' and a 'contents' material (the liquid inside it, which can be morphed down). Same carafe rendered in P6 and daz studio. What am I doing wrong? Material/render settings to follow. TIA mac

Material room gor the glass. Contents material is pretty much the same.

Render settings.

Other info.

I've tried higher Raybounces and other settings. I've also tried adding an Edge Blend node and mixing it with Reflect. Um... what else? I made the contents material a simple partly transparent material. Tried the Fresnel node too. I made all materials (Diff, Spec, etc) black at zero values. Switched Smooth Polys on.

I just ain't getting it. All advice welcome.

mac

Message edited on: 03/18/2006 10:11

In one of Ajax's freebie Material Packs, there is a Ajax_BathPool pz3 freebie. This is how Ajax setup the water in the Mat Room: Cheers DR

hi DR, Yep, I have ajax's pack. In fact, the first thing I tried was his glass shader. I didn't try the pool, but isn't that for moving water? I don't see a Turbulence node there, but maybe he did it with the Maths nodes. I'll go back and have a look at it now. cheers mac

First thought is that you may be encountering a problem similar to that which double sided polygons causes (between the mesh of the carafe and that of the liquid), so try checking "Normals_Forward" on both materials and see what happens.

Mac, This water matches the Material Room Settings. It just maybe something along the lines of what NRuddock is Suggesting that is the glitch. Cheers DR

Hi I think your refract index should be higher (2.4)? for crystal. Also, you need a reflection node as well on the glass. Split the 2 from one. ie, Reflect 0.6 Refract 0.4 for values. The liquid will need refraction as well(1.4)? or thereabouts. All the upper colors should be black (diffuse, spec, amb trans). You can tint refraction color to accent liquid.

hope this helps a little bit.. a standard refraction table... been using these for years :)

(All items except Vacuum are in alphabetical order)
(STP = Standard Temperature and Pressure)

MATERIAL Index -------------------------------------
Vacuum ...................... 1.00000 (exactly)

Air (STP).................... 1.00029
Acetone ..................... 1.36
Alcohol ..................... 1.329
Amorphous Selenium .......... 2.92
Calspar1 .................... 1.66
Calspar2 .................... 1.486
Carbon Disulfide ............ 1.63
Chromium Oxide .............. 2.705
Copper Oxide ................ 2.705
Crown Glass ................. 1.52
Crystal ..................... 2.00
Diamond ..................... 2.417
Emerald ..................... 1.57
Ethyl Alcohol ............... 1.36
Flourite .................... 1.434
Fused Quartz ................ 1.46
Heaviest Flint Glass ........ 1.89
Heavy Flint Glass ........... 1.65
Glass ....................... 1.5
Ice ......................... 1.309
Iodine Crystal .............. 3.34
Lapis Lazuli ................ 1.61
Light Flint Glass ........... 1.575
Liquid Carbon Dioxide ....... 1.20
Polystyrene ................. 1.55
Quartz 1 .................... 1.644
Quartz 2 .................... 1.553
Ruby ........................ 1.77
Sapphire .................... 1.77
Sodium Chloride (Salt) 1 .... 1.544
Sodium Chloride (Salt) 2 .... 1.644
Sugar Solution (30%) ........ 1.38
Sugar Solution (80%) ........ 1.49
Topaz ....................... 1.61
Water (20 C) ................ 1.333
Zinc Crown Glass ............ 1.517

Message edited on: 03/18/2006 13:32

Thanks for the suggestions, folks. I tried ajax's shaders again, but they look worse than what I have. Tried checking Normals Forward on both materials, but it makes no difference. The RI for normal glass is 1.52, and it's not a crystal carafe, so glass should be fine. However, I did try it, and it clears up the artifacts on the top half of the carafe, so I'll have to try some more tests with higher RIs. The RI on the liquid is 1.35. I'm beginning to wonder if it's something to do with rendering it in white space. When I set it in a scene, the results are better, but I still get odd artifacts, and I don't see why DS can render refraction in a blank scene and P6 can't. I'm sure it can. It's just me doing something wrong. The frustrating thing is that when you really get down to tweaking the nodes, practically every single setting has an effect. For example, RayBias can make a huge difference. I left it at the default setting for now, but it's yet another variable to be played with. It's great to have lots of options, but it also makes pinning problems down more difficult. mac

hi khai, I x-posted with you. Yes, I have an RI list, and as I mentioned above I'm using 1.52 (crown glass) and 1.35 for the liquid. The glass would probably be heavier than crown glass, so I'll do some more tests with higher RIs. mac

Scale was an issue in P5 with artifacts. It still is with hair in P6... I used to scale scene 1000 to 10,000 percent when dealing with RayTrace reflections. It probably still is good policy.

richardson, Unfortunately, this is for a commercial project. I can't ask people to scale entire scenes up just because poser has problems with refraction. I'm not trying to diss poser, but I've been at this for 2 days now and I'm getting a bit tired of P6, to tell you the truth. I'll repeat, I'm sure it's my own lack of knowledge that's the problem, but there's a definite weirdness in poser's refraction. Scaling may be the answer, but I really have to try and find an alternative solution. So far, I'm getting better results with normal straight-sided glasses, although I see an odd 'band' around them. I'll keep trying. Thanks for all the suggestions. mac

Understand TOTALLY. For now, you can try playing with transparency edge and falloff on the liquid... Have to bring up Trans, of couse. I had some luck there if I recall. Clears up some artifacting. Bandaid cures...

Does anyone want to try this carafe? I can zip it up and mail it. If you do, mail me at maclean@libero.it and I'll send it. It's a pretty small file. mac

LOL! a suffer free for all Words are cheap. So, yeah. I'll give it a headbang.

Well, here is where I am at with the Carafe. 1 Infinite light, straight on. Cheers DR

What were the render times on those two, DR? mac

Attached Link: http://www.daz3d.com/support/tutorial/tutorial.php?id=956

If you want, i can try too... I'm sending you an email. Don't know how DS manage "volume", but Poser don't... When a ray come in the carafe, it goes in a volume with a higher refraction index. But when it goes out, it should get back in the air.. Unfortunatly, Poser don't work with volume (and i guess DS don't) and it manage it as it was again going from air to the carafe. I made a tutorial at DAZ, but it's for Poser5 (third and fourth picture)

semidieu - I am interested in what you can come up with in P6 and what the Material Room looks like. More so what the Glass Carafe looks like. Cheers DR

hi semidieu, I already read your tutorial. I found it a few days ago when I was searching for refraction posts. I did pick up some interesting information from it. It's very well written. I've more or less solved the problem now, thanks to help from DR/Mariner. He sent me some mt5 files which I tweaked and it now works very well. I think my original problem was starting with one of ajax's shaders as a base. It's probably good for other types of glass, like windows, but it didn't work on these. Glass/liquid needs a different approach. Here's a render of what I have so far. The water and white wine don't look good against a white background, but in the scene I set up they look almost perfect. (I can't show it because the product hasn't been released yet). Thanks to everyone who gave their advice and suggestions. mac

Here are the material settings

Here are the glasses in a partial table situation (still unfinished). DR, Check your mail in a few minutes. mac