pCustom weird behavior

Hi,

When I use a pEmitter and a pCustom with the value "id" in the "Position x" field, the particles are NOT plotted in a straight line, as I would expect.
This can be fixed by setting the values for "Position y" and "Position z" to the value zero...

Is this intended behavior ? In several tutorials on YouTube I see them do the same, getting a straigth line or column of particles without having to enter zeroes in the two other fields.

Maybe I am missing some things in settings, configuration or somewhere else ?

Anybody know ?

here are some screenshots:
https://drive.google.com/file/d/1L0WViDpXcVTrkPi5hpcld_nnVl67lKEE/view?usp=sharing
https://drive.google.com/file/d/1pi05EJK5V6HN4K6VxL_voKpAXE6hxUMk/view?usp=sharing

Thanks,
Paul

What kind of emitter are you using and what size is it? Maybe the other tutorials start with smaller emitters, so that py and pz are already zero without having to set them as such?

It's just a regular pEmitter, all with default values, except for the style, which is set to blob (and increased size)

here's the code ot the two tools:

Code: Select all

{
   Tools = ordered() {
      pEmitter1 = pEmitter {
         ID = 29,
         CtrlWZoom = false,
         Inputs = {
            Style = Input { Value = FuID { "ParticleStyleBlob" }, },
            Region = Input { Value = FuID { "AllRgn" }, },
            ["BezierRgn.Polyline"] = Input {
               Value = Polyline {
               },
            },
            ["ParticleStyle.SizeControls"] = Input { Value = 1, },
            ["ParticleStyle.Size"] = Input { Value = 0.2362, },
            ["ParticleStyle.SizeOverLife"] = Input {
               SourceOp = "pEmitter1SizeOverLife",
               Source = "Value",
            },
            ["ParticleStyle.BlurOverLife"] = Input {
               SourceOp = "pEmitter1BlurOverLife2D",
               Source = "Value",
            },
         },
         ViewInfo = OperatorInfo { Pos = { 200, 23.1212 } },
      },
      pEmitter1SizeOverLife = LUTBezier {
         KeyColorSplines = {
            [0] = {
               [0] = { 0.5, RH = { 0.333333333333333, 0.5 }, Flags = { Linear = true } },
               [1] = { 0.5, LH = { 0.666666666666667, 0.5 }, Flags = { Linear = true } }
            }
         },
         SplineColor = { Red = 192, Green = 128, Blue = 64 },
         NameSet = true,
      },
      pEmitter1BlurOverLife2D = LUTBezier {
         KeyColorSplines = {
            [0] = {
               [0] = { 0.5, RH = { 0.333333333333333, 0.5 }, Flags = { Linear = true } },
               [1] = { 0.5, LH = { 0.666666666666667, 0.5 }, Flags = { Linear = true } }
            }
         },
         SplineColor = { Red = 192, Green = 128, Blue = 64 },
         NameSet = true,
      },
      pCustom1 = pCustom {
         ID = 32,
         Inputs = {
            PositionXExpression = Input { Value = "id", },
            Input = Input {
               SourceOp = "pEmitter1",
               Source = "Output",
            },
            CommentsNest = Input { Value = 0, },
            FrameRenderScriptNest = Input { Value = 0, },
         },
         ViewInfo = OperatorInfo { Pos = { 310, 23.1212 } },
      }
   }
}

I don't think the default region from a pEmitter is 'All' - usually it's Sphere. So as soon as I change it to that and make the sphere really tiny, I get this result:

Code: Select all

{
   Tools = ordered() {
      pCustom1 = pCustom {
         ID = 4,
         Inputs = {
            PositionXExpression = Input { Value = "id", },
            Input = Input {
               SourceOp = "pEmitter1",
               Source = "Output",
            },
            CommentsNest = Input { Value = 0, },
            FrameRenderScriptNest = Input { Value = 0, },
         },
         ViewInfo = OperatorInfo { Pos = { 440, -16.5 } },
      },
      pEmitter1 = pEmitter {
         ID = 1,
         CtrlWZoom = false,
         Inputs = {
            ["BezierRgn.Polyline"] = Input {
               Value = Polyline {
               },
            },
            Style = Input { Value = FuID { "ParticleStyleBlob" }, },
            ["SphereRgn.Size"] = Input { Value = 0.001, },
            ["ParticleStyle.SizeControls"] = Input { Value = 1, },
            ["ParticleStyle.Size"] = Input { Value = 0.2362, },
            ["ParticleStyle.SizeOverLife"] = Input {
               SourceOp = "pEmitter1SizeOverLife",
               Source = "Value",
            },
            ["ParticleStyle.BlurOverLife"] = Input {
               SourceOp = "pEmitter1BlurOverLife2D",
               Source = "Value",
            },
         },
         ViewInfo = OperatorInfo { Pos = { 330, -16.5 } },
      },
      pEmitter1SizeOverLife = LUTBezier {
         KeyColorSplines = {
            [0] = {
               [0] = { 0.5, RH = { 0.333333333333333, 0.5 }, Flags = { Linear = true } },
               [1] = { 0.5, LH = { 0.666666666666667, 0.5 }, Flags = { Linear = true } }
            }
         },
         SplineColor = { Red = 192, Green = 128, Blue = 64 },
         CtrlWZoom = false,
      },
      pEmitter1BlurOverLife2D = LUTBezier {
         KeyColorSplines = {
            [0] = {
               [0] = { 0.5, RH = { 0.333333333333333, 0.5 }, Flags = { Linear = true } },
               [1] = { 0.5, LH = { 0.666666666666667, 0.5 }, Flags = { Linear = true } }
            }
         },
         SplineColor = { Red = 192, Green = 128, Blue = 64 },
         CtrlWZoom = false,
      },
      pRender1 = pRender {
         Inputs = {
            _MotionBlurWarning = Input { Disabled = true, },
            Width = Input { Value = 1920, },
            Height = Input { Value = 1080, },
            ["Gamut.SLogVersion"] = Input { Value = FuID { "SLog2" }, },
            ["MaterialID.MaterialID"] = Input { Value = 1, },
            ["ObjectID.ObjectID"] = Input { Value = 1, },
            Input = Input {
               SourceOp = "pCustom1",
               Source = "Output",
            },
         },
         ViewInfo = OperatorInfo { Pos = { 660, -16.5 } },
      }
   }
}

My bad - I changed that too
changing it to Sphere reduces the variance, but still shows a wobbling line:





Edit:
Ah - Ok. I see it now
The size of the emitter must be very small indeed. You set it at 0.001 where I had it at the default 0.1
tiny details matter big time

Did you copy/paste my settings? The particles line up exactly at the grid points there.

Sander,
Yeah - I got it now
Thanks, this will make me question each and every value everywhere. It all seems to matter.

Still weird though that setting a variable in 1 axis change the other two axis's too. That should not happen in my experience. (zero experience in Fusion though)

a tiny emitter indeed resolves the issue. However...the great thing about the pCustom is that you can just position the particles wherever you want. Often I don't care about the emitter shape....I just position them with px, py, pz etc.

Still weird though that setting a variable in 1 axis change the other two axis's too. That should not happen in my experience. (zero experience in Fusion though)

It's not, though. The py and pz are unchanged. That's where the pEm put them at that time.