Iris Texture in The GIMP
by Benjamin Schram




Introduction In this Gimp tutorial I am going to show you how to create a nice eye/iris texture from scratch. In writing this tutorial, I used Gimp 2.4, but since it only uses basic filters and tools, any versión of the Gimp should work.

Step1

  • Create a new image...
  • Dimensions: 1024px by 1024px
  • Rename the base layer to "Pinched".
  • Add transparency...
  • Layer -> Transparency -> Add Alpha Channel
  • Apply "Solid Noise" filter...
  • Filters -> Render -> Solid Noise
  • Check: "Randomize"
  • Detail: 15
  • X & Y Size: 4.0






Step2

  • Apply múltiple "Difference Cloud" filters...
  • Filters -> Render -> Difference Clouds
  • Check: "Randomize"
  • Detail: 15
  • X & Y Size: 4.0
  • Repeat filter [ Control + f]
  • Repeat 5-8 times




Step3

  • Apply múltiple "Pinch" filters...
  • Filters -> Distorts -> Whirl and Pinch
  • Whirl angle: 0.00
  • Pinch Amount: 0.650
  • Radius: 1.3
  • Repeat filter [ Control + f ]






Step4


  • Ellipse select on pinched layer...
  • Use "Ellipse Select" tool [ e ]
  • Make a canvas sized circle...
  • Clik at 0,0
  • hold [ Shift ] to keep 1:1 proportions
  • Drag to 1024
  • Shrinque the selection...
  • Select -> Shrink
  • Shrink: 20px
  • Invert selection...
  • Select -> Invert
  • Clear background...
  • Edit -> Clear




Step5

  • Create a new layer...
  • Name: Polar Coords
  • Width/Heigth: 1024
  • Fill Type: Transparency
  • Select polar coords layer.
  • Apply stretched solid noise...
  • Filters -> Render -> Solid Noise
  • Check: Randomize
  • Detail: 15
  • X size: 16.0
  • Y size: 2.0




Step6

  • Apply polar coordinates to solid noise...
  • Filters -> Distorts -> Polar Coordinates
  • Circle depth %: 100.00
  • Offset Angle: 0.00
  • Check: To Polar




Step7

  • Move "Polar Coords" layer above pinched layer.
  • Set "Polar Coords" layer mode to overlay.




Step8

  • Select the pinched layer.
  • Use the "Fuzzy Select Tool" [ u ]
  • Clik in the empty space around the circle.
  • Grow the selection...
  • Select -> Grow
  • Grow Amount: 60 pixels
  • Feather the selection...
  • Select -> Feather
  • Feather: 80 pixels
  • Create a new layer
  • Name: Edge Ring
  • Width/Height: 1024
  • Fill Type: Transparency
  • Select the "Edge Ring" layer.
  • Set foreground color to black.
  • Bucket fill selection with black.
  • Select None...
  • Select -> None
  • -or-
  • [ Shift + Control + a ]
  • Make "Edge Ring" the top layer.
  • Adjust "Edge Ring" layer settings...
  • Layer Mode: Multiply
  • Opacity: 75.0




Step9


  • Create a new layer
  • Name: Color
  • Width/Height: 1024
  • Fill Type: Transparency
  • Make "Color" the top layer.
  • Pik a foreground color...
  • Value and saturation don't matter.
  • "0079ff" is a nice blue.
  • Bucket fill the "Color" layer with color.
  • Adjust "Color" layer settings...
  • Mode: Color
  • Opacity: Adjust to Taste
  • ~40% works well for "0079ff - Blue"






Step10

  • Select the "Pinched" layer
  • Use the "Fuzzy Select Tool" [ u ]
  • Clik in the empty space around the circle.
  • Invert the Selection...
  • Select -> Invert or
  • [ Control + i ]
  • Shrinque the selection.
  • This determines the size of the pupil.
  • Shrink: To Taste (~280 pixels works well)
  • Feather selection...
  • Select -> Feather
  • Feather: 30.00 pixels
  • Create a new layer...
  • Name: Pupil
  • Width/Height: 1024
  • Fill Type: Transparency
  • Make "Pupil" the top layer.
  • Switch to "Pupil" Layer.
  • Set foreground color to black.
  • Bucket fill the selection.




Step11

  • Create a new Layer...
  • Name: Color 2
  • Width/Height: 1024
  • Fill Type: Transparency
  • Move "Color 2" layer below "Pupil" layer.
  • Select the "Color 2" layer.
  • Grow selection (the previous pupil selection)...
  • Grow: 60px
  • Pik a foreground color...
  • Value and saturation don't matter.
  • "ffdd00" is a nice gold.
  • Bucket fill the selection.
  • Select None...
  • Select -> None
  • [ Shift + Control + a ]
  • Apply "Gaussian Blur" filter...
  • Filters -> Blur -> Gaussian Blur
  • Horiz: 150.0 px
  • Vert: 150.0 px
  • Blur Method: RLE
  • Adjust "Color 2" layer settings.
  • Mode: Color
  • Opacity: To Taste
  • ~45% works well for "ffdd00 - gold"



Step12

  • Tweaque "Pinched" layer brightness
  • Depending on your colors and noise patterns
  • you may want to lighten the "Pinched" layer
  • Select "Pinched" layer.
  • Adjust brightness/contrast...
  • Colors -> Brightness-Contrast
  • Brightness : To Taste (+30.0)
  • Contrast : To Taste (-30.0)


Alright, now head over to the Noob_to_Pro article on “Creating Pixar Looking Eyes” to put this texture to use. http://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/ Creating_Pixar-looking_eyes_in_Blender Here are complete and exploded view renders.





by Benjamin Schram
www.blenderart.org