Results 1 to 6 of 6

Thread: user_iblc_env with procedural or color input ?

  1. #1
    Join Date
    Nov 2011
    Location
    Paris
    Posts
    99

    Question user_ibl_env with procedural or color input ?

    Hi !

    I did some test with the new user_ibl shaders and I found that the user_ibl can only takz inputs of type file. it's not a pribleme if we want to use a hdr file, but it's not possible to use a simple ramp or constant color. Exept if we bake it into a file.
    So is there a way to use color inputs instead of file inputs ? is that a hard limitation in the fonctionnement of the user_ibl ?

    I also noticed that the environment is fliped and rotated for 180 degres when compared to the native ibl when plugin the same hdr in an environment lookup.

    I know there was the same flip issue with the old ibl node. so which is the good one now ? rotating the ibl is easy, but fliping it means doing it in another programme. the user_ibl seems to ignore the place2dTexture when using a maya file instead of a mentalRay file.

    edit: could a moderator correct the error in the title ? (the "c" in user_ibl_env), I can't change it. thanks !
    Last edited by MiniZun; April 24th, 2012 at 11:15. Reason: title correction

  2. #2
    Join Date
    Dec 2005
    Location
    Chicago
    Posts
    2,632

    Default

    The old IBL (the one in Maya) has always been flipped incorrectly. The user_ibl_env is correctly positioned.

    The native IBL would take what was plugged into the camera as an environment and bake it to texture (using the resolution string option) In that way it would take a procedural or ramp but you may have lost detail in the baking process.

    user_ibl_env has direct access to an un-resized texture. So if you needed a procedural you would need to bake it to be sure it worked correctly and apply as an HDR texture.

    If your HDR was acquired normally you should not need to flip it, this is unlike the Maya IBL connection that required flipping. The user_ibl_env should remove that step.
    "Don't let anyone drive you crazy when you know it's in walking distance."

    "Don't argue with an idiot, they will drag you down to their level and beat you over the head with experience."

    http://elementalray.wordpress.com/

  3. #3
    Join Date
    Nov 2011
    Location
    Paris
    Posts
    99

    Default

    What I don't understand is why I have different flip result with native IBL and user_ibl_env when using the same hdr file. Both have a different position.

    Do you know any way to bypass the need for a file ? I don't understand why there is this limitation

  4. #4
    Join Date
    Dec 2005
    Location
    Chicago
    Posts
    2,632

    Default

    Is the native IBL you're using by plugging a texture into the Maya IBL connection?

    And there's not a bypass I know of, it requires a texture. Other connections don't work well for me. (crash or error) It's not really a limitation, it's DCC package agnostic so it accepts a texture.

    To be honest, procedurals tend to produce muddy lighting.
    Last edited by Remydrh; April 24th, 2012 at 18:50.
    "Don't let anyone drive you crazy when you know it's in walking distance."

    "Don't argue with an idiot, they will drag you down to their level and beat you over the head with experience."

    http://elementalray.wordpress.com/

  5. #5
    Join Date
    Nov 2011
    Location
    Paris
    Posts
    99

    Default

    Ah no, I never use the maya IBL, when I refer to using naitve IBL, I'm using a mi_lookup_spherical plugged in the miEnvironment slot of the camera.

    And for the procedural, I just wanted to use a simple ramp (vertical light grey to dark grey) as ibl lighting and area lights for main lighting to simulate a studio.

  6. #6
    Join Date
    Dec 2005
    Location
    Chicago
    Posts
    2,632

    Default

    I think mi_lookup_spherical uses radians and user_ibl is degrees. That might be part of the problem.

    Procedurals are convenient but not always the best choice. You can probably make some nicer ones in Nuke or HDR Light Studio.
    "Don't let anyone drive you crazy when you know it's in walking distance."

    "Don't argue with an idiot, they will drag you down to their level and beat you over the head with experience."

    http://elementalray.wordpress.com/

Posting Permissions

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