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Help? - wonky shadows?

hacsarthacsart Posts: 2,025
edited July 2019 in Art Studio

Using an HDRI from hdrihaven and IBLmaster  for my car renders usually gives good shadows, but some imported models seem to only cast partial shadows, as if some parts aren't stopping the light.... Other models have no issues... Any ideas? I;'m sure it  has to be something with the mesh, but I can;t figure out what..

Any input would be greatly appreciated..
example:

 

 

bentley_test_mall_parking_lot_1.jpg
1680 x 1050 - 1M
Post edited by hacsart on

Comments

  • Sven DullahSven Dullah Posts: 7,621
    edited July 2019

    Does converting it to SubD make any difference? Try increasing trace distance? Lowering shadow bias?

    Post edited by Sven Dullah on
  • hacsarthacsart Posts: 2,025

    Good idea, but no change..

  • Sven DullahSven Dullah Posts: 7,621

    Does it cast proper shadows with a DS distant light onto a plane?

  • Matt_CastleMatt_Castle Posts: 2,571

    I'm fishing a bit in the dark here, but are the problematic surfaces actually opaque from both sides in a render? I'm wondering if it's possible that your import format might have somehow set the material to be one-sided somehow.

    (At the same point, which shader is actually set on those surfaces? Imported models presumably won't use Iray settings, and trying to use a non-Iray material can have some bugs).

  • Sven DullahSven Dullah Posts: 7,621
    edited July 2019
    Matt_Castle said:

    I'm fishing a bit in the dark here, but are the problematic surfaces actually opaque from both sides in a render? I'm wondering if it's possible that your import format might have somehow set the material to be one-sided somehow.

    (At the same point, which shader is actually set on those surfaces? Imported models presumably won't use Iray settings, and trying to use a non-Iray material can have some bugs).

    I assume that's a 3DL render, and the DS default shader usually does not have problems with backfaces. But yeah, could be worth a try inverting normals for some or all the surfaces to see if it makes a difference. Also in preferences/interface one could try enabling the backface lighting.

    @hacsart

    If you're rendering in 3DL, the AoA SS base shader has an option to flip normals, if you don't want to do it with the geometry editor.

    Post edited by Sven Dullah on
  • Matt_CastleMatt_Castle Posts: 2,571
    Sven Dullah said:

    I assume that's a 3DL render

    D'oh. Yeah, I read "HDRI" and thus immediately thought "Iray", but then I don't have/use IBLmaster myself (and only use 3DL for some very specific jobs), so I forgot that's exactly what it's supposed to do.

    Still, seeing as it is specifically imported models, I think it is worth checking which way the model's faces are pointing, as I've definitely had the "Oh yeah, all the faces are inside out, that's why it's not working" problem in some renderering programs.

     

  • Sven DullahSven Dullah Posts: 7,621
    Matt_Castle said:
     

    Still, seeing as it is specifically imported models, I think it is worth checking which way the model's faces are pointing, as I've definitely had the "Oh yeah, all the faces are inside out, that's why it's not working" problem in some renderering programs.

    Couldn't agree morelaugh

  • hacsarthacsart Posts: 2,025
    edited July 2019

    Hmm.. Normals seem ok, and flipping them didn;t help (just as an experiment ).. BUT.. taking the model in question, and popping it into a scene with a pane and one standard DAZ plane primitive - and Voila! - so is it something in IBLmaster,?? time to experiment more..

    shadow_test.jpg
    1680 x 1050 - 448K
    Post edited by hacsart on
  • Sven DullahSven Dullah Posts: 7,621
    hacsart said:

    Hmm.. Normals seem ok, and flipping them didn;t help (just as an experiment ).. BUT.. taking the model in question, and popping it into a scene with a pane and one standard DAZ plane primitive - and Voila! - so is it something in IBLmaster,?? time to experiment more..

    Interestingsurprise Running out of ideas, would love to know, if you find a solution;) I remember IBLM having some issues but there was an update that seemed to work alright. Something related to normals IIRC. What if you slap a plane under it in IBLM and hide the shadowcatcher? Still wonky shadows?

  • hacsarthacsart Posts: 2,025

    Juts did a fresh download and re-install of IBL master - will  keep on playing and see what I can discover..

    Sven Dullah said:
    hacsart said:

    Hmm.. Normals seem ok, and flipping them didn;t help (just as an experiment ).. BUT.. taking the model in question, and popping it into a scene with a pane and one standard DAZ plane primitive - and Voila! - so is it something in IBLmaster,?? time to experiment more..

    Interestingsurprise Running out of ideas, would love to know, if you find a solution;) I remember IBLM having some issues but there was an update that seemed to work alright. Something related to normals IIRC. What if you slap a plane under it in IBLM and hide the shadowcatcher? Still wonky shadows?

     

  • hacsarthacsart Posts: 2,025
    edited July 2019

    Fixed --- when in doubt RTFM!!!  Section in the IBLmaster doc about clipped shadows... increased the Maximum Tracing Distance in the IBL Light Settings to 5000...

     

    shadow_test_2.jpg
    1680 x 1050 - 1M
    Post edited by hacsart on
  • Sven DullahSven Dullah Posts: 7,621

    yes Lookin good:)

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