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Thread: Maya Curve node and IOR Curves

  1. #11
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    So I'm just not happy at all with the look of my metals using this setup. Plus, I don't see how to get textures working in it very effectively. Maybe I'm just not seeing something the right way. I have a modified version of this I'm working on based on some work I did with this kind of stuff a few years back. I have this slightly tweaked solution working nicely with painted textures as well. I'll post up a little later once I get it all sorted.

  2. #12
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    Looking forward to seeing what your modified version is and what some renders look like
    Working with textures this way is definitely a pain.

  3. #13
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    Definitely! I was working on stainless steel a few years ago and emailed a company that has machines to conduct measurements at certain wavelengths. So I got the n and k for stainless steel at r,g, and b wavelengths. I couldn't find stainless steel anywhere on line back then. Not sure if it's there now. Also ended up getting some bronze and brass too. Going to add those values to the presets drop down!

  4. #14
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    Sweeeeeet. The geekiness in me is totally coming out with this. Don't forget to include the n and k values for the stainless steel in the presets too. I'd be really interested in those numbers. I don't think I've ever seen those numbers anywhere. How did you get a company to do that for you? Did you just email them and ask if they could do it? Or was there more persuasion on your part that was needed?

    I'll try and work up some metals this weekend too. It will be really interesting to see the comparisons of the different methodologies.

  5. #15
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    Quote Originally Posted by thebeals View Post
    Sweeeeeet. The geekiness in me is totally coming out with this.
    hehehe! me too!

    I sold Cutco in college, baby! I threw on that old school salesman charm...dude didn't stand a chance. Putty in ma' hands. lolol! Nah, really the guy was super cool. I got the email addy off their site, exchanged a few emails explaining what I was doing and why I wanted the values, and he hit me right back. So I got greedy and got a few other metals while I was at it. Brass and bronze. They proved elusive as well. Couldn't find them online anywhere. But now they're gonna be in this here script.

    I already got them in the presets drop down. Also, modded the script so it's super easy to add new presets. You don't have to alter 2 different arrays anymore. I put one global array at the very top. You just slap in a new preset and it populates the drop down and the values for the function at the same time.

  6. #16
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    OK, I've got the new version complete. I messed around quite a bit with this metal concept a few years ago and this setup worked best for me. I have a blank file texture node being created now, but that could be altered to use the file texture node plugged into the material if it's there, or the final node in a big shading network if it's there, etc.

    I'm using the diffuse slot, and checking metal material. This works and still adds up to 1 on the edge because we have 1 in the diffuse and 1 in the reflection color on the edge. 1 x 1 = 1. I'm pretty sure I'm right about how the mia and the metal material slot works but if I'm wrong here feel free to correct me. I know it was giving me the visual result I wanted at least, which was nice reflections at glancing angles. The bonus is when checking metal material I think we're still getting that metallic edge darkening thing that happens with metal material checked.

    Also, I'm leaving Schlick 0 degree set to 1. I wasn't happy with this though and played with it on a case by case basis. Some metals, like steel, I thought looked way better with 0 degree mixed back to like 0.9 and bending that brdf curve more to like 13 or so. I played with it though and it changed from metal to metal so I'm leaving it at 1 and leaving it up to artistic discretion. Seems like the best bet.

    Let me know what you think! I loved this technique but quit using it because it was a pain to set up. Not anymore!! I'll start using this again because it's scripted and easy to set up now.
    Attached Files Attached Files

  7. #17
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    Looks like I need to go back and re investigate. This isn't doing exactly what I thought it should. I guess the old method is best for now. I'll check it out when I get back home.

  8. #18
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    Just did a quick mod so the newer version of the script (with the new presets) now simply plugs the remap nodes into the reflection color. This was the initial behavior.
    Attached Files Attached Files

  9. #19
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    Awesome work! I noticed that you have the .outcolorR going to the r channel, it should be outvalue. Right now colored metals don't have a colored reflection because of this.

    I did a few comparisons:

    Using your script to generate complex Ior's, I get this for Gold:
    MiaComplexIOR.jpgMilaComplexIOR.jpg

    They look nearly identical EXCEPT it appears the mia reflects the physical object area light much more intensly than the mila does. However, it reflects the ibl similarly. Below is an exposured down image to show the difference:
    mia_exposureDown.jpg
    mila_exposureDown.jpg

    I am assuming the mila is more accurate in this regard.. or is the mila just being clamped?
    Attached Images Attached Images

  10. #20
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    I also did a comparison between mila and mia using an ior of 30 instead of the custom fresnel. The difference is much more noticeable.

    Mila30IOR.jpgmia30IOR.jpg


    It seems that there is some odd behavior going on with the Mila at the upper left hand side on the grazing angle..

    I also ticked the MIA metal material on and off when the diffuse color was white and it didn't make any noticeable difference.

    I think I'm liking the custom fresnel look more and the render times are about the same. The color does seem to be off from what I think of when I see gold though, but that could just be the environment I am using.
    Last edited by thebeals; September 11th, 2014 at 21:45.

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