Actually, I think the reason it looks correct in 8 and 16 bit is
because values hit 0 before they reach the edge of the "square sampled
area".
Which would be the same as clamping some of the very low end in a float image.
The problem is, in the case of a radial gradient like this one, that
the pixels at the corners are obviously further away from the center
than say a pixel in the middle of the right edge. And indeed they get
a smaller value because of it. BUT, the sampling region is square, so
the X pixel coordinate at which they reach 0 is the same. If you were
to use an Expression node instead of a gamma to show all pixels that
are "not 0", you would see exactly the same problem.
On Wed, Jul 20, 2011 at 10:58 AM, chris <ze.m...@gmx.net> wrote:
>
> yeah, strange.. the effect happens actually on any simple
> blur... looks like the gaussian blur is not really spreading
> uniformly, but more "boxy". boosting the quality level
> doesn't help either. ironically, if you switch the filter to
> box it gets more like a circle.
>
> also, if i replicate the same setup in shake, it looks like
> a circle in 8 and 16bit, but gets wonky in float. so maybe a
> gaussian blur is tricky to do in float?
>
> examples below
> ++ c.
>
>
> nuke:
> *********
>
> set cut_paste_input [stack 0]
> add_layer {rgba rgba.beta}
> ColorWheel {
> inputs 0
> gamma 0.45
> name ColorWheel1
> selected true
> xpos -52
> ypos -353
> }
> Shuffle {
> red alpha
> green alpha
> blue alpha
> name Shuffle1
> selected true
> xpos -52
> ypos -268
> }
> Transform {
> scale 0.5
> center {960 540}
> name Transform1
> selected true
> xpos -52
> ypos -244
> }
> set N1e524f50 [stack 0]
> Blur {
> channels rgb
> size 50
> filter box
> quality 80
> name Blur1
> label "size: \[value size]"
> selected true
> xpos -52
> ypos -203
> }
> Gamma {
> channels rgb
> value 8
> name Gamma1
> selected true
> xpos -52
> ypos -152
> }
> push $N1e524f50
> Blur {
> channels rgb
> size 50
> quality 80
> name Blur2
> label "size: \[value size]"
> selected true
> xpos 65
> ypos -202
> }
> Gamma {
> channels rgb
> value 8
> name Gamma2
> selected true
> xpos 65
> ypos -148
> }
>
>
>
> shake:
> ******
>
>
> ColorWheel1 = ColorWheel(1920, 1080, 4, 0, 1, 1, 1);
> Bytes1 = Bytes(ColorWheel1, 2);
> Reorder1 = Reorder(Bytes1, "aaaa");
> Move2D1 = Move2D(Reorder1, 0, 0, 0, 1, 0.5, xScale, 0, 0, width/2,
> height/2, "default", xFilter, "trsx", 0, 0, 0.5, 0, 0, time);
> Blur1 = Blur(Move2D1, 100, xPixels/GetDefaultAspect(), 0, "gauss",
> xFilter, "rgba");
> Gamma1 = Gamma(Blur1, 8, rGamma, rGamma, 1);
>
>
>
>
>
>
>
> On 7/20/11 at 7:16 PM, ron...@gmail.com (Ron Ganbar) wrote:
>
>> Hi Randy,
>> Still wrong on my end... :-(
>> Played with Blur11 - didn't seem to make any difference.
>> Thanks for trying.
>>
>> Ron Ganbar
>> email: ron...@gmail.com
>> tel: +44 (0)7968 007 309 [UK]
>> +972 (0)54 255 9765 [Israel]
>> url: http://ronganbar.wordpress.com/
>>
>>
>>
>> On 20 July 2011 18:12, Randy Little <randyslit...@gmail.com> wrote:
>>
>>> Merry Xmas its fixed. The weird thing is that fixing was
>>
>> to turn off crop
>>>
>>> to format in the blur11 then turn it back on. ????? So
>>
>> I don't know.
>>>
>>> strange. maybe it was holding onto the format from pre
>>
>> crop some how for
>>>
>>> whatever reason.
>>>
>>> set cut_paste_input [stack 0]
>>> version 6.2 v3
>>> push $cut_paste_input
>>> Sparkles {
>>> size 30
>>> motion 200
>>> direction 60
>>> fadeTolerance 152
>>> broken_affected 6.6
>>> broken_start 0.3
>>> broken_holes 0.186
>>> sparks_angle 77
>>> name Sparkles1
>>> selected true
>>> xpos -111
>>> ypos -205
>>> }
>>> Crop {
>>> box {0 0 2048 1556}
>>> name Crop4
>>> selected true
>>> xpos -106
>>> ypos -157
>>> }
>>> Group {
>>> name ExpoBlur2
>>> selected true
>>> xpos -106
>>> ypos -103
>>> addUserKnob {20 ExpoBlur}
>>> addUserKnob {14 size R 0 5}
>>> size 0.2
>>> addUserKnob {41 strength T Grade160.white}
>>> addUserKnob {41 curve T Grade160.gamma}
>>> addUserKnob {41 black_clamp l "black clamp" T
>>
>> Grade160.black_clamp}
>>>
>>> addUserKnob {41 white_clamp l "white clamp" -STARTLINE T
>>> Grade160.white_clamp}
>>> addUserKnob {41 crop l "crop to format" T Blur11.crop}
>>> }
>>> Input {
>>> inputs 0
>>> name Input1
>>> xpos 389
>>> ypos -32
>>> }
>>> Dot {
>>> name Dot328
>>> xpos 423
>>> ypos -4
>>> }
>>> set N1c441b60 [stack 0]
>>> add_layer {rgba rgba.beta}
>>> Blur {
>>> size {{parent.size**7} {parent.size**7}}
>>> crop {{parent.Blur11.crop}}
>>> name Blur17
>>> xpos 714
>>> ypos 100
>>> }
>>> push $N1c441b60
>>> Blur {
>>> size {{parent.size**6} {parent.size**6}}
>>> crop {{parent.Blur11.crop}}
>>> name Blur16
>>> xpos 589
>>> ypos 96
>>> }
>>> push $N1c441b60
>>> Blur {
>>> size {{parent.size**5} {parent.size**5}}
>>> crop {{parent.Blur11.crop}}
>>> name Blur15
>>> xpos 499
>>> ypos 104
>>> }
>>> push $N1c441b60
>>> Blur {
>>> size {{parent.size**4} {parent.size**4}}
>>> crop {{parent.Blur11.crop}}
>>> name Blur14
>>> xpos 389
>>> ypos 106
>>> }
>>> push $N1c441b60
>>> Blur {
>>> size {{parent.size**3} {parent.size**3}}
>>> crop {{parent.Blur11.crop}}
>>> name Blur13
>>> xpos 287
>>> ypos 108
>>> }
>>> push 0
>>> push $N1c441b60
>>> Blur {
>>> size {{parent.size*2} {parent.size*2}}
>>> crop {{parent.Blur11.crop}}
>>> name Blur12
>>> xpos 174
>>> ypos 108
>>> }
>>> push $N1c441b60
>>> Blur {
>>> size {{parent.size} {parent.size}}
>>> name Blur11
>>> xpos 53
>>> ypos 115
>>> }
>>> Merge2 {
>>> inputs 7+1
>>> operation plus
>>> name Merge243
>>> xpos 389
>>> ypos 232
>>> }
>>> set N1c474b50 [stack 0]
>>> Grade {
>>> channels rgba
>>> white 1.02
>>> gamma 0.435
>>> white_clamp true
>>> name Grade160
>>> xpos 389
>>> ypos 311
>>> }
>>> Output {
>>> name Output1
>>> xpos 389
>>> ypos 438
>>> }
>>> push $N1c474b50
>>> Viewer {
>>> input_process false
>>> name Viewer1
>>> selected true
>>> xpos 570
>>> ypos 426
>>> }
>>> end_group
>>>
>>> Randy S. Little
>>> http://www.rslittle.com <http://reel.rslittle.com>
>>>
>>>
>>>
>>>
>>>
>>> On Thu, Jul 21, 2011 at 00:52, Ron Ganbar
>>
>> <ron...@gmail.com> wrote:
>>>
>>>> set cut_paste_input [stack 0]
>>>> version 6.2 v4
>>>> push $cut_paste_input
>>>> Sparkles {
>>>> size 30
>>>> name Sparkles1
>>>> selected true
>>>> xpos -304
>>>> ypos 3346
>>>> }
>>>> Crop {
>>>> box {0 0 2048 1556}
>>>> name Crop4
>>>> selected true
>>>> xpos -304
>>>> ypos 3374
>>>> }
>>>> Group {
>>>> name ExpoBlur2
>>>> selected true
>>>> xpos -304
>>>> ypos 3422
>>>> addUserKnob {20 ExpoBlur}
>>>> addUserKnob {14 size R 0 5}
>>>> size 2
>>>> addUserKnob {41 strength T Grade160.white}
>>>> addUserKnob {41 curve T Grade160.gamma}
>>>> addUserKnob {41 black_clamp l "black clamp" T
>>
>> Grade160.black_clamp}
>>>>
>>>> addUserKnob {41 white_clamp l "white clamp" -STARTLINE T
>>>> Grade160.white_clamp}
>>>> addUserKnob {41 crop l "crop to format" T Blur11.crop}
>>>> }
>>>> Input {
>>>> inputs 0
>>>> name Input1
>>>> xpos 389
>>>> ypos -32
>>>> }
>>>> Dot {
>>>> name Dot328
>>>> xpos 423
>>>> ypos -4
>>>> }
>>>> set Nbb6ed990 [stack 0]
>>>> add_layer {rgba rgba.beta}
>>>> Blur {
>>>> size {{parent.size**7 i} {parent.size**7 i}}
>>>> crop {{parent.Blur11.crop i}}
>>>> name Blur17
>>>> xpos 714
>>>> ypos 100
>>>> }
>>>> push $Nbb6ed990
>>>> Blur {
>>>> size {{parent.size**6 i} {parent.size**6 i}}
>>>> crop {{parent.Blur11.crop i}}
>>>> name Blur16
>>>> xpos 606
>>>> ypos 103
>>>> }
>>>> push $Nbb6ed990
>>>> Blur {
>>>> size {{parent.size**5 i} {parent.size**5 i}}
>>>> crop {{parent.Blur11.crop i}}
>>>> name Blur15
>>>> xpos 499
>>>> ypos 104
>>>> }
>>>> push $Nbb6ed990
>>>> Blur {
>>>> size {{parent.size**4 i} {parent.size**4 i}}
>>>> crop {{parent.Blur11.crop i}}
>>>> name Blur14
>>>> xpos 389
>>>> ypos 106
>>>> }
>>>> push $Nbb6ed990
>>>> Blur {
>>>> size {{parent.size**3 i} {parent.size**3 i}}
>>>> crop {{parent.Blur11.crop i}}
>>>> name Blur13
>>>> xpos 287
>>>> ypos 108
>>>> }
>>>> push 0
>>>> push $Nbb6ed990
>>>> Blur {
>>>> size {{parent.size*2 i} {parent.size*2 i}}
>>>> crop {{parent.Blur11.crop i}}
>>>> name Blur12
>>>> xpos 174
>>>> ypos 108
>>>> }
>>>> push $Nbb6ed990
>>>> Blur {
>>>> size {{parent.size} {parent.size}}
>>>> name Blur11
>>>> xpos 53
>>>> ypos 111
>>>> }
>>>> Merge2 {
>>>> inputs 7+1
>>>> operation plus
>>>> name Merge243
>>>> xpos 389
>>>> ypos 283
>>>> }
>>>> Grade {
>>>> channels rgba
>>>> gamma 6
>>>> white_clamp true
>>>> name Grade160
>>>> xpos 389
>>>> ypos 311
>>>> }
>>>> set Nc73fb7f0 [stack 0]
>>>> Viewer {
>>>> viewerProcess SHOWLinAsFilm3D
>>>> input_process false
>>>> name Viewer1
>>>> xpos 570
>>>> ypos 426
>>>> }
>>>> push $Nc73fb7f0
>>>> Output {
>>>> name Output1
>>>> xpos 389
>>>> ypos 438
>>>> }
>>>> end_group
>>>>
>>>
>>>
>>> _______________________________________________
>>> Nuke-users mailing list
>>> Nuke-users@support.thefoundry.co.uk,
>>
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>>>
>> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/
>> nuke-users
>>>
>>
>>
>> -----
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>
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