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Unacceptable Black Smears on Characters Skin

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  • mjc1016mjc1016 Posts: 15,001
    edited May 2016
    IsaacNewton said:

    I assume the Vertical tiling =1 and horrizontal tiling =1 (as shown in the screenshot) does mean that there is no tiling applied.

    Right....1 in vert and horiz. is the texture map(s) are placed once on the mesh...2x is twice each direct...so that would be 4 copies of the map fit to the mesh...and so on.

    Post edited by mjc1016 on
  • barbultbarbult Posts: 24,247

    There is another way to invoke tiling. That is in the Image Editor built into the surfaces pane. The Image Editor's Instance Tiling allows you to tile each image map individually, rather than tiling the entire surface with the controls you showed. I think the chance that your sand texture is tiled with the Image Editor Instance Tiling is about as close to zero as it could get, unless you edited the surface manually to set it. I only bring the idea up for completeness.

  • mjc1016mjc1016 Posts: 15,001
    barbult said:

    There is another way to invoke tiling. That is in the Image Editor built into the surfaces pane. The Image Editor's Instance Tiling allows you to tile each image map individually, rather than tiling the entire surface with the controls you showed. I think the chance that your sand texture is tiled with the Image Editor Instance Tiling is about as close to zero as it could get, unless you edited the surface manually to set it. I only bring the idea up for completeness.

    3Delight only has the 'master' tiling...the instance tiling in the Image Editor is only available for Iray.

  • barbultbarbult Posts: 24,247
    mjc1016 said:
    barbult said:

    There is another way to invoke tiling. That is in the Image Editor built into the surfaces pane. The Image Editor's Instance Tiling allows you to tile each image map individually, rather than tiling the entire surface with the controls you showed. I think the chance that your sand texture is tiled with the Image Editor Instance Tiling is about as close to zero as it could get, unless you edited the surface manually to set it. I only bring the idea up for completeness.

    3Delight only has the 'master' tiling...the instance tiling in the Image Editor is only available for Iray.

    I thought this whole thread was about Iray problems. Am I mistaken?

  • CDS1aCDS1a Posts: 5
    edited May 2016
    mjc1016 said:
    CDS1a said:

    I'm getting something very similar happening on my renders.

    Black triangle-shaped smudges that appear in a constant places on the figure.

    Moving the camera and the sun-sky light source does not change the appearance.

    Using local spotlights instead of the sun-sky done does nothing.

    If I repose the character, the problem "moves" as you can see in the third image.

    Interestingly, the flaw survives substtuting a NEW old-school 3Delight skin material (fourth image)

    I am using DS 4.9.1.30 on an nVidia. Drivers are up to date

     

    All of those are renders?

    Which figure/character?

    And does the problem survive if you change to "Base" under the resolution in the Parameters?

    1) Yes. That is 4 separate renders. Same camera position in all.
     First image is lit with Dome+ Scene, Second is only local spotlight with disk-shaped emitter. Third is the same local spotlight and the character's waist is twisted. Fourth has a different G2F skin/shader of the old-school 3Delight variety. All are of the same character.

    2) The character is G2F TeenJosie.

    3) The problem survives when I set the resolution level to base. I get big triangles instead of a number of small ones.

    4) I am using the timeline facility to lay out frames of a comic. I don't do any tweening. Every 10 frames has a new pose, and I render a number of camera views per new pose.This problem tends to come up in files that have a lot of keyframes in them. For each key frame, I usually select children from the root of the character and hit the Key+ icon in the timeline window.

    My fix-it technique for Black Smudge is to save out my character when it is first designed as a scene subset. When I get this problem, I load the SceneSubset character, and copy and paste the pose frames from the old to the new copy. After some fiddling, I have 2 identical characters in 2 identical timeline sequences. The previous time this happened on different character in same file, the problem went away when I did this copy-paste cloning technique. For the current character, I had a bad frame, applied this character cloning, but it only fixed another frame, not the frame shown. 

    5) There is another bug of long standing that if you key frame spotlights, the frame following the key frame will have some lights go to "specular only" mode in the illumination field. Somewhere behind the scenes there is a numerical problem. Similar numerical issues might be influencing this Black Smudge thing.

     

    Post edited by CDS1a on
  • ToborTobor Posts: 2,300

    @IsaacNewton, the screenshot you show is for a 3Delight shader. If you're seeing your artifact(s) in Iray, you should first convert the shader to Iray, and make adjustments there. While 3Delight shaders are eventually converted for use in Iray, the conversion is automatic, with no telling how the vavious parameters are really applied.

    For Iray, these smudgy artifacts tend to be either shadow terminator artifacts, or the world-center bug that doesn't appear to be fixed yet. With the latter, if you translate the character (and lights) to 0, 0, 0, and the problem goes away, it's the world-center bug. Usually, but not always, that bug is related to transparency maps, but lacking lots of examples, it's hard to say there might not be other causes for it, too. 

  • CDS1aCDS1a Posts: 5
    edited May 2016
    Tobor said:

    @IsaacNewton, the screenshot you show is for a 3Delight shader. If you're seeing your artifact(s) in Iray, you should first convert the shader to Iray, and make adjustments there. While 3Delight shaders are eventually converted for use in Iray, the conversion is automatic, with no telling how the vavious parameters are really applied.

    For Iray, these smudgy artifacts tend to be either shadow terminator artifacts, or the world-center bug that doesn't appear to be fixed yet. With the latter, if you translate the character (and lights) to 0, 0, 0, and the problem goes away, it's the world-center bug. Usually, but not always, that bug is related to transparency maps, but lacking lots of examples, it's hard to say there might not be other causes for it, too. 

    1) My renders are all iRay renders.(first page of this thread). I plugged in the 3Delight shader just to illustrate that it seems to be a numerical problem.

    2) This render is located at (5691, 23, 5261). I just moved it to (  91, 23,   61). Actually, I translated the parent Group nodes for Cameras, People, Lights, and Ground, and the problem went away.  Hooray!

    3) This phenomenon needs a descriptive name. I vote for "Black Smudge". "Shadow Terminator" names the cause, not the effect.

    Thanks!!

    Post edited by CDS1a on
  • mjc1016mjc1016 Posts: 15,001

    If moving it back to the center/closer to world origin fixed it, then it is not the shadow terminator problem (it's not really a bug, so much as a failing of the render algorithms to handle 'low' poly meshes).

    It's the world-center bug and needs to be reported to CS...

  • IsaacNewtonIsaacNewton Posts: 1,300
    edited May 2016
    Tobor said:

    @IsaacNewton, the screenshot you show is for a 3Delight shader. If you're seeing your artifact(s) in Iray, you should first convert the shader to Iray, and make adjustments there. While 3Delight shaders are eventually converted for use in Iray, the conversion is automatic, with no telling how the vavious parameters are really applied.

     

    Hi Tobor,

    The attached image shows that indeed the smudge is not present when rendered with 3Delight. The same lighting conditions were used for the Iray render where the smudge does appear. There are no alternative shaders provided in the PTH pack and no indication that it should be rendered with 3Delight (as far as I could see). The promo pic suggests compatability with Iray.

     

    PTH.jpg
    1290 x 1125 - 594K
    Post edited by IsaacNewton on
  • ToborTobor Posts: 2,300
    CDS1a said:

    3) This phenomenon needs a descriptive name. I vote for "Black Smudge". "Shadow Terminator" names the cause, not the effect.

    Shadow terminatore artifact is the industry-wide term for the phenomenon, It affects more than just Iray. However, from a technical standpoint, what you're seeing is something different from this particular artifact, and is I believe an issue related to D|S and Iray.

    IsaacNewton said:

    The attached image shows that indeed the smudge is not present when rendered with 3Delight. The same lighting conditions were used for the Iray render where the smudge does appear. There are no alternative shaders provided in the PTH pack and no indication that it should be rendered with 3Delight (as far as I could see). The promo pic suggests compatability with Iray.

    I don't know the product, but as you are using a 3Delight shader with Iray, you really can't expect full control over the outcome. If you want to exorcise the smudges, you can go with luck, or you could convert the shader to Iray (shaders come with 4.8+ for this), and then tweak. Relying on the automatic conversion of 3DL shaders to Iray material settings is hit-or-miss. You can't review how the shader was converted, because it happens behind your back at render time.

    Vendors of products sold here don't have to provide the same tools they used to create their promo renders, or a description of how they made the promos. Wish they did, but it just doesn't work that way. Given that you're trying to reproduce a promo image for a currently sold product (it is, isn't it?), I'd think the best thing is see if the vendor has a forum presence here, and ask him or her directly.

  • IsaacNewtonIsaacNewton Posts: 1,300
    Tobor said:
    CDS1a said:

     

    I don't know the product, but as you are using a 3Delight shader with Iray, you really can't expect full control over the outcome.

    Hi Tobor,

    You seem quite convinced that I'm using a 3Delight shader though you don't explain why you think that. As you say that you don't know the product, I have told you that there is no indication in the product that I have found that the shaders are for 3Delight, whereas the promo picture indicates Iray compatability. So, I'd be happy to know what it is that you know about the shaders for this product that I don't know... do tell.

  • Richard HaseltineRichard Haseltine Posts: 101,014

    The easy way to test is to select a surface (with the Surface Selection tool or from the list in the Surface pane) and see what shader is listed at top-left of the Surface pane when in the Editor tab

  • ToborTobor Posts: 2,300
    IsaacNewton said:

    You seem quite convinced that I'm using a 3Delight shader though you don't explain why you think that. As you say that you don't know the product, I have told you that there is no indication in the product that I have found that the shaders are for 3Delight, whereas the promo picture indicates Iray compatability. So, I'd be happy to know what it is that you know about the shaders for this product that I don't know... do tell.

    It's quite simple: the attachment in your post is for a 3DL shader. Your screen shot shows, among other things, Ambient settings. There are no such settings in an Iray shader.

    http://www.daz3d.com/forums/discussion/comment/1176611/#Comment_1176611

    The promo picture says nothing about "Iray compatibility." It just says that one shot used the Iray renderer. No one (other than the vendor) knows what adjustments were made to take that promo. 

  • mjc1016mjc1016 Posts: 15,001

    Daz Studio Default  is the basic 3Delight shader for Studio.

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