Using Shift-W command in B-Spline node creates artefact

This first diagram is a closed loop drawn by the B-Spline node. Simply created by clicking 4 points, and closing the loop. So far so good.

Fig1.jpg (49.05 KiB) Viewed 1826 times

The problem occurs when I use the mouse to select one of the points (e.g. the lower left), and then use the Shift-W command while moving the cursor left-to-right. This is meant to bring out the line towards or away from the point. It works.

But the problem is, when the line is brought towards the point, it creates an un-wanted artefact which I have highlighted in the diagram below.

Figu2.jpg (27.68 KiB) Viewed 1826 times

This is merely a rough example, but when I draw precise shapes using the B-Spline, that artefact means the shape I've drawn contains an unsightly tiny squiggle that Fusion's B-Spline adds.

My guess is it is a bug in the B-Spline node. Or am I doing something to make the artefact occur?

I've noticed the same thing, even though I don't use b-splines that often. You can maybe try changing the Border Width to something like .001 and see if that helps.

Hey Roger
B Splines are great for smooth shapes.
Bezier Splines are great for sharp corners.
My suggestion would be to pick the best tool for the job. If your shape has sharp corners, try using the Bezier and see if that helps.
B Splines can be glitchy if you try to push them past their limits in terms of sharpness.

Sadi

Hey Roger
B Splines are great for smooth shapes.
Bezier Splines are great for sharp corners.
My suggestion would be to pick the best tool for the job. If your shape has sharp corners, try using the Bezier and see if that helps.
B Splines can be glitchy if you try to push them past their limits in terms of sharpness.

Sadi

The BSpline is the tool that enables me to draw a heart shape. I'm not aware of how to draw a heart shape using the Polygon node.

My question is: Is this a bug in the BSpline node?

How does one draw a heart shape in Fusion without introducing little artefacts?

Code: Select all

{
   Tools = ordered() {
      Polygon1 = PolylineMask {
         DrawMode = "ModifyOnly",
         DrawMode2 = "InsertAndModify",
         CtrlWZoom = false,
         Inputs = {
            MaskWidth = Input { Value = 1920, },
            MaskHeight = Input { Value = 1080, },
            PixelAspect = Input { Value = { 1, 1 }, },
            ClippingMode = Input { Value = FuID { "None" }, },
            Polyline = Input {
               SourceOp = "Polygon1Polyline",
               Source = "Value",
            },
            Polyline2 = Input {
               Value = Polyline {
               },
               Disabled = true,
            },
         },
         ViewInfo = OperatorInfo { Pos = { 2970, -148.5 } },
      },
      Polygon1Polyline = BezierSpline {
         SplineColor = { Red = 173, Green = 255, Blue = 47 },
         NameSet = true,
         KeyFrames = {
            [1009] = { 0, Flags = { Linear = true, LockedY = true }, Value = Polyline {
                  Closed = true,
                  Points = {
                     { X = -0.00499999988824129, Y = 0.16666667163372, LX = -0.013582756950044, LY = 0.0537822320367503, RX = 0.00894788986481546, RY = 0.0544442713640035 },
                     { X = 0.0925000014901161, Y = 0.231111110316382, LX = -0.045665939397241, LY = 0.0704657519951371, RX = 0.0845263570163622, RY = -0.130430105877271 },
                     { X = -0.00249999977648258, Y = -0.284444432258606, LX = 0.0299888766079861, LY = 0.227853360336542, RX = -0.0360652788177122, RY = 0.229839801932482 },
                     { X = -0.104999997317791, Y = 0.228888893789715, LX = -0.0764104087913766, LY = -0.138529007280251, RX = 0.0421271332515569, RY = 0.0763748033966779 }
                  }
               } }
         }
      }
   },
   ActiveTool = "Polygon1"
}

Edit: More to the point, yes, I get the same artifact. It looks like it only appears on one node. I thought it was always the first one created, but that may not be true. Testing a bit more...

Looks like it only happens on the second point in the spline, and it might be pulled out by either of the nodes adjacent to that point, or by tightening the second point itself. Very odd, and certainly a bug.

[quote="Bryan Ray"]

Code: Select all

{
   Tools = ordered() {
      Polygon1 = PolylineMask {
         DrawMode = "ModifyOnly",
         DrawMode2 = "InsertAndModify",
         CtrlWZoom = false,
         Inputs = {
            MaskWidth = Input { Value = 1920, },
            MaskHeight = Input { Value = 1080, },
            PixelAspect = Input { Value = { 1, 1 }, },
            ClippingMode = Input { Value = FuID { "None" }, },
            Polyline = Input {
               SourceOp = "Polygon1Polyline",
               Source = "Value",
            },
            Polyline2 = Input {
               Value = Polyline {
               },
               Disabled = true,
            },
         },
         ViewInfo = OperatorInfo { Pos = { 2970, -148.5 } },
      },
      Polygon1Polyline = BezierSpline {
         SplineColor = { Red = 173, Green = 255, Blue = 47 },
         NameSet = true,
         KeyFrames = {
            [1009] = { 0, Flags = { Linear = true, LockedY = true }, Value = Polyline {
                  Closed = true,
                  Points = {
                     { X = -0.00499999988824129, Y = 0.16666667163372, LX = -0.013582756950044, LY = 0.0537822320367503, RX = 0.00894788986481546, RY = 0.0544442713640035 },
                     { X = 0.0925000014901161, Y = 0.231111110316382, LX = -0.045665939397241, LY = 0.0704657519951371, RX = 0.0845263570163622, RY = -0.130430105877271 },
                     { X = -0.00249999977648258, Y = -0.284444432258606, LX = 0.0299888766079861, LY = 0.227853360336542, RX = -0.0360652788177122, RY = 0.229839801932482 },
                     { X = -0.104999997317791, Y = 0.228888893789715, LX = -0.0764104087913766, LY = -0.138529007280251, RX = 0.0421271332515569, RY = 0.0763748033966779 }
                  }
               } }
         }
      }
   },
   ActiveTool = "Polygon1"
}

Thanks for that code for Polygon node. Question: Is there a way of making the control lines, for each of the top points, perfectly symmetrical to each other? Or is the only way to eyeball it?

If it's not important that it remain a single spline, you could use a Transform node to reflect it, like so:

Code: Select all

{
   Tools = ordered() {
      Polygon1 = PolylineMask {
         DrawMode = "ModifyOnly",
         DrawMode2 = "InsertAndModify",
         Inputs = {
            BorderWidth = Input { Value = 0.0032, },
            MaskWidth = Input { Value = 1920, },
            MaskHeight = Input { Value = 1080, },
            PixelAspect = Input { Value = { 1, 1 }, },
            ClippingMode = Input { Value = FuID { "None" }, },
            Polyline = Input {
               SourceOp = "Polygon1Polyline",
               Source = "Value",
            },
            Polyline2 = Input {
               Value = Polyline {
               },
               Disabled = true,
            },
            Point0 = Input { Value = { 0.5, 0.6666666716337 }, },
            Point1 = Input { Value = { 0.5, 0.2155555677414 }, },
         },
         ViewInfo = OperatorInfo { Pos = { 260, 77.0606 } },
      },
      Polygon1Polyline = BezierSpline {
         SplineColor = { Red = 173, Green = 255, Blue = 47 },
         NameSet = true,
         KeyFrames = {
            [0] = { 0, RH = { 336.333333333333, 0.333333333333333 }, Flags = { Linear = true, LockedY = true }, Value = Polyline {
                  Points = {
                     { X = 0, Y = 0.1666666716337, RX = 0.00483596727995762, RY = 0.0560634441634746, PublishID = "Point0" },
                     { X = 0.0925000014901161, Y = 0.231111110316382, LX = -0.045665939397241, LY = 0.0704657519951371, RX = 0.0845263570163622, RY = -0.130430105877271 },
                     { X = 0, Y = -0.2844444322586, LX = 0.0299888766079861, LY = 0.227853360336542, PublishID = "Point1" }
                  }
               } },
            [1009] = { 1, LH = { 672.666666666667, 0.666666666666667 }, Flags = { Linear = true, LockedY = true }, Value = Polyline {
                  Points = {
                     { X = -0.00499999988824129, Y = 0.16666667163372, RX = 0.00894788986481546, RY = 0.0544442713640035, PublishID = "Point0" },
                     { X = 0.0925000014901161, Y = 0.231111110316382, LX = -0.045665939397241, LY = 0.0704657519951371, RX = 0.0845263570163622, RY = -0.130430105877271 },
                     { X = -0.00249999977648258, Y = -0.284444432258606, LX = 0.0299888766079861, LY = 0.227853360336542, PublishID = "Point1" }
                  }
               } }
         }
      },
      Transform1_1 = Transform {
         Inputs = {
            FlipHoriz = Input { Value = 1, },
            Input = Input {
               SourceOp = "Polygon1_1",
               Source = "Mask",
            },
         },
         ViewInfo = OperatorInfo { Pos = { 359.333, 128.576 } },
      },
      Transform1 = Transform {
         Inputs = {
            FlipHoriz = Input { Value = 1, },
            Input = Input {
               SourceOp = "Polygon1",
               Source = "Mask",
            },
         },
         ViewInfo = OperatorInfo { Pos = { 363.937, 29.7879 } },
      },
      Merge1 = Merge {
         CtrlWZoom = false,
         Inputs = {
            Background = Input {
               SourceOp = "Polygon1",
               Source = "Mask",
            },
            Foreground = Input {
               SourceOp = "Transform1",
               Source = "Output",
            },
            PerformDepthMerge = Input { Value = 0, },
         },
         ViewInfo = OperatorInfo { Pos = { 392.667, 81.9091 } },
      },
      Polygon1_1 = PolylineMask {
         DrawMode = "InsertAndModify",
         DrawMode2 = "InsertAndModify",
         Inputs = {
            MaskWidth = Input { Value = 1920, },
            MaskHeight = Input { Value = 1080, },
            PixelAspect = Input { Value = { 1, 1 }, },
            ClippingMode = Input { Value = FuID { "None" }, },
            Polyline = Input {
               SourceOp = "Polygon1_1Polyline",
               Source = "Value",
            },
            Polyline2 = Input {
               Value = Polyline {
               },
               Disabled = true,
            },
            Point0 = Input { Value = { 0.5, 0.6666666716337 }, },
            Point1 = Input { Value = { 0.5, 0.2155555677414 }, },
         },
         ViewInfo = OperatorInfo { Pos = { 255.396, 175.848 } },
      },
      Polygon1_1Polyline = BezierSpline {
         SplineColor = { Red = 173, Green = 255, Blue = 47 },
         NameSet = true,
         KeyFrames = {
            [0] = { 0, RH = { 336.333333333333, 0.333333333333333 }, Flags = { Linear = true, LockedY = true }, Value = Polyline {
                  Closed = true,
                  Points = {
                     { X = 0, Y = 0.1666666716337, LX = -8.64499592114262e-005, LY = -0.145961965060756, RX = 0.00483596727995762, RY = 0.0560634441634746, PublishID = "Point0" },
                     { X = 0.0925000014901161, Y = 0.231111110316382, LX = -0.045665939397241, LY = 0.0704657519951371, RX = 0.0845263570163622, RY = -0.130430105877271 },
                     { X = 0, Y = -0.2844444322586, LX = 0.0299888766079861, LY = 0.227853360336542, RX = -0.00054264758850853, RY = 0.130927017613396, PublishID = "Point1" }
                  }
               } },
            [1009] = { 1, LH = { 672.666666666667, 0.666666666666667 }, Flags = { Linear = true, LockedY = true }, Value = Polyline {
                  Closed = true,
                  Points = {
                     { X = -0.00499999988824129, Y = 0.16666667163372, LX = -0.0237203303778779, LY = -0.144328564996663, RX = 0.00894788986481546, RY = 0.0544442713640035, PublishID = "Point0" },
                     { X = 0.0925000014901161, Y = 0.231111110316382, LX = -0.045665939397241, LY = 0.0704657519951371, RX = 0.0845263570163622, RY = -0.130430105877271 },
                     { X = -0.00249999977648258, Y = -0.284444432258606, LX = 0.0299888766079861, LY = 0.227853360336542, RX = -0.0192701768612451, RY = -0.146413438873029, PublishID = "Point1" }
                  }
               } }
         }
      },
      Merge1_1 = Merge {
         Inputs = {
            Background = Input {
               SourceOp = "Polygon1_1",
               Source = "Mask",
            },
            Foreground = Input {
               SourceOp = "Transform1_1",
               Source = "Output",
            },
            PerformDepthMerge = Input { Value = 0, },
         },
         ViewInfo = OperatorInfo { Pos = { 388.062, 180.697 } },
      }
   }
}


I published the centerline points so I could enter an exact x-coordinate there. The outline version is not closed, to prevent having a line down the middle. The solid version must have a closed spline for the fill to work.

Very odd, and certainly a bug.

I received a message from Blackmagic saying this bug would be corrected in the next version.