Page 4 of 5 FirstFirst ... 2345 LastLast
Results 46 to 60 of 62

Thread: So what's up with the Cook Torrance shader?

  1. #46
    Pitifully not. But fortunately we have DP_LightGroup.
    Thank you again, Denis!



    Gerardo

  2. #47
    It always makes me sad when you come in to a thread to check on a long standing bug, and, of course, it hasn't been fixed

  3. #48
    Not so newbie member lardbros's Avatar
    Join Date
    Apr 2003
    Location
    England
    Posts
    5,854
    Hmmmmmm.... it's a sad day!

    This is why I struggle sometimes... I try and make something with my nodes, and always put it down to user error if I can't get something to work, when you guys are different, you are so clever you know what it should be doing, and blame the software because it's at fault!

    Shame it hasn't been fixed!! Do many shader bugs get fixed at the mo? Antti is probably hard at work on CORE's nodal stuff!!!
    LairdSquared | 3D Design & Animation

    Desk Work:
    HP Z840, Dual Xeon E5-2690 v2, 32GB RAM, Quadro K5000 4GB
    Desk Home:
    HP Z620, Dual Xeon E5-2680, 80GB RAM, Geforce 1050 Ti 4GB

  4. #49
    oh corks
    Join Date
    Aug 2010
    Location
    end of the line
    Posts
    888
    Umm... has anybody ever tried the AS Shader Node Blinn/Phong/CookTorrance/OrenNayar/Lambert plugin from this page?

    http://www.neko.ne.jp/~asagi/P2P/Plugins/lay.html


    Or to put it another way: Hey! Try this!
    .
    .
    Last edited by stiff paper; 05-02-2011 at 07:41 AM.

  5. #50
    President, the LightWave Group robpowers3d's Avatar
    Join Date
    Feb 2003
    Location
    Burbank, CA
    Posts
    902
    Quote Originally Posted by chunderburger View Post
    can anyone at nt read this and please fix. rob/matt/chuck/lino?
    We are aware of this and are looking into it.
    Rob Powers

    President, NewTek LightWave 3D Group
    Burbank, CA

  6. #51
    Not so newbie member lardbros's Avatar
    Join Date
    Apr 2003
    Location
    England
    Posts
    5,854
    Quote Originally Posted by robpowers3d View Post
    We are aware of this and are looking into it.
    Good news... and thanks for the reassurance. Always great to hear that old issues are being looked into!
    LairdSquared | 3D Design & Animation

    Desk Work:
    HP Z840, Dual Xeon E5-2690 v2, 32GB RAM, Quadro K5000 4GB
    Desk Home:
    HP Z620, Dual Xeon E5-2680, 80GB RAM, Geforce 1050 Ti 4GB

  7. #52
    Traitor
    Join Date
    Feb 2003
    Location
    Perth, Australia
    Posts
    460
    Quote Originally Posted by lardbros View Post
    Good news... and thanks for the reassurance. Always great to hear that old issues are being looked into!
    Some NT folks were nice enough to take time out of their very busy schedule to look at this issue (including putting up with my very rusty matrix math skills) for a number of hours one night not too long ago.

    (I wanted to give kudos to NT where it was warranted)
    Last edited by mattc; 05-03-2011 at 12:38 AM.

  8. #53
    Not so newbie member lardbros's Avatar
    Join Date
    Apr 2003
    Location
    England
    Posts
    5,854
    Quote Originally Posted by mattc View Post
    Some NT folks were nice enough to take time out of their very busy schedule to look at this issue (including putting up with my very rusty matrix math skills) for a number of hours one night not too long ago.

    (I wanted to give kudos to NT where it was warranted)
    Good stuff... and thanks to both you and Newtek for spending hours on the things like this!! It's very valuable... and shows, again and again, what a great community we have here!


    Thanks!!
    LairdSquared | 3D Design & Animation

    Desk Work:
    HP Z840, Dual Xeon E5-2690 v2, 32GB RAM, Quadro K5000 4GB
    Desk Home:
    HP Z620, Dual Xeon E5-2680, 80GB RAM, Geforce 1050 Ti 4GB

  9. #54
    Fantastic news Rob, glad this is being looked into. it's one of a number of niggles in the renderer which need resolving to achieve realism. Thanks to the Newtek Staff!

  10. #55
    oh corks
    Join Date
    Aug 2010
    Location
    end of the line
    Posts
    888
    So... nobody is actually interested enough in having working specular shaders that they've even bothered to try the node I linked to?

    Huh.

  11. #56
    Traitor
    Join Date
    Feb 2003
    Location
    Perth, Australia
    Posts
    460
    I think everyone is interested in getting the included nodes working....not to say a 3rd party node isn't useful or anything like that.

  12. #57
    Super Member Captain Obvious's Avatar
    Join Date
    Dec 2004
    Location
    London
    Posts
    4,502
    Quote Originally Posted by Cardboard View Post
    So... nobody is actually interested enough in having working specular shaders that they've even bothered to try the node I linked to?

    Huh.
    Not interested enough to bother circumventing the fact that I got blocked from the website by some content filter bullmanure.
    Are my spline guides showing?

  13. #58
    I haven't tested it, but tbh, I don't really bother much with spec as a rule these days. It has it's uses, but I got a bit sick of fighting it, so I haven't bothered for a while!

  14. #59
    Quote Originally Posted by Cardboard View Post
    So... nobody is actually interested enough in having working specular shaders that they've even bothered to try the node I linked to?

    Huh.
    Don't know if you have even bothered to try the node you linked to, but at least here, the Cook-Torrance and Phong models don't provide correct results in their backlighting distribution. The effect is interesting (and might be used for some rim lighting effects) but the thing is that their highlight distribution and intensities in backlighting is not consistent with the direction of the incoming light according to the direction of the viewer.

    We suppose that the farther we measure from the center of the highlight, the lesser will be the intensity of the highlight; but the Cook-Torrance node and Phong node (as well as their shader versions) don't behave as expected. There, the back highlight intensities are higher than the center of the highlight, besides, the light is reflected in angles where the surface normal is not oriented between the direction of incoming light and the direction of the viewer (specular highlight spreads in a 180° range). Both cases don't represent the specular reflection of real materials. This odd behavior can not be excused by a fresnel effect and it can't be solved with their highlight/IOR parameters (the highlight parameter is not present in the shader and none of these parameters are present in the Phong model where the situation is more acute).

    Options are always welcome, but for more predictable results and more extensive usages, I prefer the LightGroup node from Denis Pontonnier



    Gerardo

  15. #60
    evil bump, was the bug fixed?
    LW vidz   DPont donate   LightWiki   RHiggit   IKBooster   My vidz

Page 4 of 5 FirstFirst ... 2345 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •