26 replies to this topic

[Tom De Boefer]

And sorry it's a premultiply problem :-). In NUKE its works directly without changing a single option, but I prefer to use Fusion. I added a screenshot for comparison, also the source Fusion .comp is included.

I tried al the .settings related to this at vfxpedia, but the outlines remain. even with boolean operators..nothing works.

Can anyone open the comp file and have a look? The goal is to have the same result as in NUKE, so without the white outline.



Many many thanks!

screenshot url:
http://imageupper.co...501852480_1.jpg

Attached Files

•  pot.zip   1.08MB   28 downloads

[iLuso]

Hi Tom.
You can use MatteControl with gamma 0.45 and post multiply.

[Tilt]

The pot has edge pixels which are brighter than their corresponding alpha channels. This creates the bright edge when it's being merged. The reason it doesn't show up in Nuke is because the tif is in sRGB color space. Nuke removes the sRGB gamma when it reads the image, Fusion just reads the image as it is...

You can fix it in Fusion, but to me this looks like the tif is already slightly flawed. Alpha (un)premultiplication hasn't been done correctly when it was converted to sRGB.

Is that tif file coming from Fusion/Nuke or has it been rendered like that in a 3D app?


edit: ah, I see you've already found out

[Tilt]

Hi Tom.
You can use MatteControl with gamma 0.45 and post multiply.

that would break the alpha channel though...

[Tom De Boefer]

Tilt, it's a 3D render from 3ds max. Please tell me this is fixable :-)

[Tom De Boefer]

Hi Tom.
You can use MatteControl with gamma 0.45 and post multiply.

That gives a black border, am realy looking for a perfect solution, there must be way to do it properly in Fusion.

[redoddity]

Probably a bit backwards, but going back to linear (without premultipication), and then back to sRGB( with premultiplication) works:

{
Tools = ordered() {
Merge1 = Merge {
Inputs = {
PerformDepthMerge = Input { Value = 0, },
Background = Input {
SourceOp = "Background1",
Source = "Output",
},
Foreground = Input {
SourceOp = "Gamut1_1",
Source = "Output",
},
},
ViewInfo = OperatorInfo { Pos = { 825, 346.5, }, },
},
Gamut1_1 = GamutConvert {
CtrlWZoom = false,
Inputs = {
OutputSpace = Input { Value = FuID { "sRGB", }, },
PreDividePostMultiply = Input { Value = 1, },
Input = Input {
SourceOp = "Gamut1",
Source = "Output",
},
},
ViewInfo = OperatorInfo { Pos = { 825, 313.5, }, },
},
Background1 = Background {
CurrentSettings = 2,
CustomData = {
Settings = {
[1] = {
Tools = ordered() {
Background1 = Background {
Inputs = {
Gradient = Input {
Value = Gradient {
Colors = {
[0] = { 0, 0, 0, 1, },
[1] = { 1, 1, 1, 1, },
},
},
},
TopLeftRed = Input { Value = 0.207843154668808, },
TopLeftBlue = Input { Value = 0.584313750267029, },
GlobalOut = Input { Value = 100, },
TopLeftGreen = Input { Value = 0.462745130062103, },
Height = Input { Value = 1556, },
Width = Input { Value = 2048, },
},
CtrlWZoom = false,
ViewInfo = OperatorInfo { Pos = { 569, 354, }, },
CustomData = {
},
},
},
},
},
},
Inputs = {
GlobalOut = Input { Value = 100, },
Width = Input { Value = 2048, },
Height = Input { Value = 1556, },
TopLeftRed = Input { Value = 0.505882352941176, },
TopLeftGreen = Input { Value = 0.717647058823529, },
TopLeftBlue = Input { Value = 0.819607843137255, },
Gradient = Input {
Value = Gradient {
Colors = {
[0] = { 0, 0, 0, 1, },
[1] = { 1, 1, 1, 1, },
},
},
},
},
ViewInfo = OperatorInfo {
Pos = { 715, 346.5, },
Flags = {
ShowName = true,
},
},
},
Gamut1 = GamutConvert {
Inputs = {
SourceSpace = Input { Value = FuID { "sRGB", }, },
Input = Input {
SourceOp = "Loader1",
Source = "Output",
},
},
ViewInfo = OperatorInfo { Pos = { 825, 280.5, }, },
},
Loader1 = Loader {
Clips = {
Clip {
ID = "Clip1",
Filename = "comp:\\pot.tif",
FormatID = "TiffFormat",
StartFrame = -1,
LengthSetManually = true,
TrimIn = 0,
TrimOut = 0,
ExtendFirst = 0,
ExtendLast = 0,
Loop = 0,
AspectMode = 0,
Depth = 0,
TimeCode = 0,
GlobalStart = 0,
GlobalEnd = 0,
},
},
Inputs = {
EnableClipList = Input { Value = 0, },
},
ViewInfo = OperatorInfo {
Pos = { 825, 181.5, },
Flags = {
ShowModes = true,
},
},
},
},
}

[redoddity]

Also, is it an sRGB problem? or was the image rendered with a colored background? (Just checking, because if so, then a simple premultiply with color might work)

[Tom De Boefer]

Redoddity that is perfect! There is no more alpha but putting layers behind the pot does work, how is that possible?

PS: It's rendered on black.

[redoddity]

If it was rendered on black then it is as Tilt suggested, something odd in the gamma conversion and premultiplication.

[Tilt]

What do you mean by "there is no more alpha"? That the alpha channel has disappeared?!

[xmare]

just curious - a "post-multiply with alpha" in loader Import tab works for me...

[ChadCapeland]

just curious - a "post-multiply with alpha" in loader Import tab works for me...

It shouldn't. That setting assumes a linear image, which this is not.

- Chad

[Tom De Boefer]

What do you mean by "there is no more alpha"? That the alpha channel has disappeared?!

It did in my previous comp, when I applied a gamut, my alpha was completely white over the entire frame, but I was still able to put layers behind it. AFAIK it was just a viewport glitch because now it works like it should.

Also, when color correcting a single layer after the gamut I have to enable Pre Divide/Post Multiply in the CC options to avoid a small fringe. When enabled the result is perfect.

In Fusion 7 we'll be able to adjust an sRGB gamut in the loader itself, that's very good news.

[Tilt]

Also, when color correcting a single layer after the gamut I have to enable Pre Divide/Post Multiply in the CC options to avoid a small fringe. When enabled the result is perfect.

yes, that's how it has to be done.