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Thread: AR4.0.2 Smudge and Flat Knife Bug (?)

  1. #1
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    AR4.0.2 Smudge and Flat Knife Bug (?)

    Lima has excellent videos in the following thread which illustrate this behavior very clearly.
    http://www2.ambientdesign.com/forums...919#post441919
    It looked buggy so I'm questioning here. Basically: do this:

    1/ Put oil paint of the canvas with oil brush (or tube paint)
    2/ Use the smudge tool to move the paint out from the blob; it begins to pale as if taking on the white in the canvas (see illustration below).
    3/ Change to a zero-load flat knife (most settings - result will vary slightly, but generally same outcome) and work the smudged area.
    RESULT, the smudged area quickly takes on the original hue.

    Is this buggy, or expected behavior?
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    Last edited by byroncallas; 03-18-2013 at 03:59 PM. Reason: Subscribe
    // "Appreciation fosters well-being. Be well." - Byron
    //
    My ArtRage Paintings Here
    // My Comprehensive AR4 & 3 Thread Here
    64 bit Win8Pro, 16GB Ram, Intel i7 Quad Core - 8 threads; Wacom Intuios 4

  2. #2
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    Hi Byron. What's happening here is that the color of the paint isn't changing, when you using the soft blender ( or other digital blending tools ) it artificially makes the paint more translucent as you smear the paint around, while maintaining the paint thickness. The palette knife ( flat and edge modes ) uses a different model as it's not a digital blender and it doesn't deal with transparency which is why it gets darker again.
    Dave
    Resident Bug-Hunter
    Ambient Design

  3. #3
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    One note on 'hue' - The hue of the paint isn't changing here, it's transparency is. There will be a minor visual shift in hue if the paper is not pure grey in colour (because the pigment is transparent you get a blend of the blue and the slight yellow of the paper) but the pigment itself has not changed hue at all.
    Matt
    ArtRage UI
    Ambient Design.

  4. #4
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    Hi Dave, Matt: Thanks for the explanation. A change from opaque to transparent and back to opaque makes sense of the behavior. I hadn't thought of the soft blender as a transparency inducer, though I see it in practice all the time. I never connected the dots. Thanks for describing what is happening so clearly.
    // "Appreciation fosters well-being. Be well." - Byron
    //
    My ArtRage Paintings Here
    // My Comprehensive AR4 & 3 Thread Here
    64 bit Win8Pro, 16GB Ram, Intel i7 Quad Core - 8 threads; Wacom Intuios 4

  5. #5
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    Hi! I think IMHO that this is the soft to learn (and teach) color mixing. Mixing and blending colors with the flat knife tool, gives one the visual sensation of manualy making it, for real!!!

    The use of a viscous paint (liquidity) would increase this feeling. Digital paint viscosity is being researched by many...

    one example:
    https://wwwx.cs.unc.edu/~geom/papers/documents/dissertations/baxter04.pdf

    well, AR has this kind of viscous paint. Viscous paint this is the point with this post. I than started to experiment with the soft knife tool. These experiments are momentaneously focused on color mixing. There seems to be many possibilities, and also different findings that where not seem before. This transparency hue stuff is one of them, as Dave and Matt pointed out. Dealing with visual surface filigranas and odd findings brings us to understand what is going on and so be sure that what we are doing is reproducible. So, I'm posting this image with some questions included.

    I am posting this same thing in the other thread, just to close my participation there

    Thank you
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    Last edited by Lima; 03-19-2013 at 09:15 AM.

  6. #6
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    Hi Lima,

    In the outlined part of your image, the soft palette knife has caused the paint to become translucent. If you were to place a layer underneath, then paint a different colour on the layer, you will see it starting to show through the paint. With the digital blenders we are able to make thick paint become translucent like this ( more of a digital effect than a realistic one ). When you then use the palette knife, it doesn't have the ability to do that, its blending is based on smearing around the paint thickness, using the colour of the paint and it ignores translucent paint. It's a limitation of the model basically. I hope this is of some help, let me know if you need any further information.
    Dave
    Resident Bug-Hunter
    Ambient Design

  7. #7
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    Byron, dear frriend, thanks for posting in this technical area

    Dave, thanks. Now I fully understood.

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