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Vray fur with Mari vector paint

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  • Vray fur with Mari vector paint

    Mari has the ability to paint vector maps that could be used in the vray fur map channels to "comb" the hair. I'm trying to get a handle on the best settings in Mari to produce maps that are compliant with vray fur. The following are excerpts from the Mari manual (http://thefoundry.s3.amazonaws.com/p..._UserGuide.pdf) followed by my questions:

    Code:
    The Paint Flow Vectors and Paint Normal Vectors modes are an alpha blend between the vectors. The Nudge Flow Vectors and Nudge Normal Vectors modes add the vectors together to get the blend result. The paint flow and paint normal modes convert the painted vectors into the texture’s tangent space before creating the associated blend. This conversion takes into account the orientation of the texture on the model’s surface.
    
    [FONT=sans-serif]The flow and normal vector modes refer to how the vectors are allowed to act in xyz space. Flow modes keep the vectors flat against the surface of the model. Normal modes allow the vectors to protrude outwards from the model in tangent z space. The type of vectors you want to paint may influence which paint blending modes you use. For example, flow modes are most often going to be used for flow maps, while you may prefer using normal modes for creating normal maps
    This part is the most confusing to me. I would initially think that I would want to paint flow rather than paint normal, however since, according to the vray manual, "the blue component is the offset along the surface normal" perhaps I want to paint a normal map rather than a flow map?

    Code:
    The Vector (Screen Space) shader is for viewing vector (colors) in tangent space, while the Vector (World Space) shader is for viewing vector (colors) in world space.
    Do vray fur maps work with screen space or world space?

    Code:
    [FONT=sans-serif]File Space fields allow you to  set whether the channel or image should be exported as a Normal file (in the way Mari stores them), as a 
    [/FONT]
    [FONT=sans-serif]Vector file (-1.0 to +1.0 range), or as a Vector (flipped Y) file, which is the same as the Vector file in terms of range, but inverts the vectors in the Y direction.
    [/FONT]
    [/FONT]
    Code:
    
    
    I assume Vray looking for a -1.0 to 1.0 map as opposed to 0 to 1 or flipped Y, is that correct?

    Vray says
    Code:
    The red component is offset along the u texture direction, the green component is the offset along the v texture direction, and the blue component is the offset along the surface normal
    while Mari says:

    Code:
    Left to Right:          pink (RGB: 1, 0.5, 0.5) 
    Right to Left: turquoise         (RGB: 0, 0.5, 0.5) 
    Top to Bottom: green      (RGB: 0.5, 1, 0.5) 
    Bottom to Top: purple      (RGB: 0.5, 0, 0.5)
    Are these two ways of saying the same thing? or are the two color schemes different and thus incompatible?





  • #2
    Originally posted by sharktacos View Post
    This part is the most confusing to me. I would initially think that I would want to paint flow rather than paint normal, however since, according to the vray manual, "the blue component is the offset along the surface normal" perhaps I want to paint a normal map rather than a flow map?
    VRayFur expects something more similar to normal maps, yes. However you can perhaps use a flow map to bend the normal directions - not sure how Mari works here.

    Do vray fur maps work with screen space or world space?
    VRayFur expects the maps to be in tangent space.

    I assume Vray looking for a -1.0 to 1.0 map as opposed to 0 to 1 or flipped Y, is that correct?
    V-Ray expects the map components to be between 0 and 1.

    Are these two ways of saying the same thing? or are the two color schemes different and thus incompatible?
    Looks to be more or less the same thing. I'm not sure if the V component needs to be flipped or not - you'll have to test.

    Best regards,
    Vlado
    I only act like I know everything, Rogers.

    Comment


    • #3
      Yes, I think Mari can paint in 0-1 tangent normal space too using the paint normal vectors mode. I'll do some tests and report back, thanks.

      Another thing I am unclear on from the Vray side is the initial direction and bend direction maps. If I understand it, it looks like the initial direction is the beginning direction of the fur and bend is the end direction, so it would begin with the trajectory of the initial and end with the bend making an arch. So one would theoretically need two different maps for this. However, all paint programs that I am aware of that can paint vectors (Mari, Modo) output a single fur direction map, not two. So other than just putting that map into both slots, I'm not quite sure how to use these two map slots. Could you shed some insight into this please?

      Comment


      • #4
        Originally posted by sharktacos View Post
        However, all paint programs that I am aware of that can paint vectors (Mari, Modo) output a single fur direction map, not two.
        This is an odd statement; not sure how Mari or Modo work, but surely it is possible to paint more than one map on a surface? What if you needed one for anisotropy and another one for normal map?

        So other than just putting that map into both slots, I'm not quite sure how to use these two map slots. Could you shed some insight into this please?
        You can certainly put the same map in both slots, and it will work. More interesting effects are possible with two maps, but if you don't have them, there's that.

        Best regards,
        Vlado
        I only act like I know everything, Rogers.

        Comment


        • #5
          Wow this is seriously cool! Just played around with it, it works! very nice.
          Dmitry Vinnik
          Silhouette Images Inc.
          ShowReel:
          https://www.youtube.com/watch?v=qxSJlvSwAhA
          https://www.linkedin.com/in/dmitry-v...-identity-name

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          • #6
            Originally posted by vlado View Post
            This is an odd statement; not sure how Mari or Modo work, but surely it is possible to paint more than one map on a surface? What if you needed one for anisotropy and another one for normal map?
            Yes, you certainly can have differnt maps for various purposes. I simply meant that the resulting vector normal map from Mari would produce a single map to drive the fur direction, rather that a combination of two maps.

            I believe it may be possible to output two maps for Modo (one for direction and another for height) but then the later would be a grey scalar rather than an RGB so it would not work with Vray's bend. So I was just trying to wrap my head around the way Vray fur is set up. It certainly does work to put a normal map into both slots.

            Comment


            • #7
              Originally posted by Morbid Angel View Post
              Wow this is seriously cool! Just played around with it, it works! very nice.
              Cool. What was your workflow? Did you use vector normal in Mari?

              Comment


              • #8
                Originally posted by sharktacos View Post
                I believe it may be possible to output two maps for Modo (one for direction and another for height) but then the later would be a grey scalar rather than an RGB so it would not work with Vray's bend. So I was just trying to wrap my head around the way Vray fur is set up. It certainly does work to put a normal map into both slots.
                We are also working to port the VRayFurStyler plugin to Maya, so that you can at least directly see the effect of the two maps right in the viewport.

                Best regards,
                Vlado
                I only act like I know everything, Rogers.

                Comment

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