iris texture in the Gimp
By benjamín schram.



Introduction in this Gimp tutorial i am going todo show you how todo create a nice eye/iris texture from scratch. In writing this tutorial, y 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 todo 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 diference cloud filters.
  • filters -> render -> diference clouds.
  • check: randomize.
  • detail: 15
  • x & y size: 4.0
  • repeat filter [ control + f]
  • repeat 5-8 times.



Step3.
  • apply múltiple Pinch filters.
  • filters -> diestorts -> whirl and Pinch.
  • whirl angle: 0.00
  • Pinch amount: 0.650
  • Radius: 1.3
  • repeat filter [ control + f ]





Step4.
  • elipse select on pinched layer.
  • use elipse select tool [ e ]
  • make a canvas sized circle.
  • click at 0,0
  • hold [ shift ] todo kep 1:1 proportions.
  • drag todo 1024
  • Shrink the selection.
  • select -> Shrink.
  • Shrink: 20px.
  • invert selection.
  • select -> invert.
  • clear background.
  • edit -> clear.



Step5.
  • create a new layer.
  • name: Polar cords.
  • width/heigth: 1024
  • fill type: transparency.
  • select Polar cords 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 todo solid noise.
  • filters -> diestorts -> Polar coordinates.
  • circle depth %: 100.00
  • offset angle: 0.00
  • check: todo Polar.



Step7.
  • move Polar cords layer above pinched layer.
  • set Polar cords layer mode todo overlay.



Step8.
  • select the pinched layer.
  • use the fuzzy select tool [ u ]
  • click in the Empty space around the circle.
  • grow the selection.
  • select -> grow.
  • grow amount: 60 píxeles.
  • feather the selection.
  • select -> feather.
  • feather: 80 píxeles.
  • create a new layer.
  • name: Edge ring.
  • width/height: 1024
  • fill type: transparency.
  • select the Edge ring layer.
  • set foreground color todo 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 dont matter.
  • 0079f is a nice blue.
  • bucket fill the color layer with color.
  • adjust color layer settings.
  • mode: color.
  • opacity: adjust todo taste.
  • ~40% works well for 0079f - Blue.





Step10.
  • select the pinched layer.
  • use the fuzzy select tool [ u ]
  • click in the Empty space around the circle.
  • invert the selection.
  • select -> invert or.
  • [ Control + I ]
  • Shrink the selection.
  • this determines the size of the pupil.
  • Shrink: todo taste (~280 píxeles works well)
  • feather selection.
  • select -> feather.
  • feather: 30.00 píxeles.
  • create a new layer.
  • name: pupil.
  • width/height: 1024
  • fill type: transparency.
  • make pupil the top layer.
  • switch todo pupil layer.
  • set foreground color todo 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 dont matter.
  • fdd00 is a nice gold.
  • bucket fill the selection.
  • select none.
  • select -> none.
  • [ shift + control + a ]
  • apply Gaussian Blur filter.
  • filters -> blur -> Gaussian Blur.
  • horizontal: 150.0 px.
  • vert: 150.0 px.
  • blur method: RLE
  • adjust color 2 layer settings.
  • mode: color.
  • opacity: todo taste.
  • ~45% works well for fdd00 - Gold.



Step12.
  • tweak pinched layer brightness.
  • depending on your colors and noise patterns.
  • you may want todo lighten the pinched layer.
  • select pinched layer.
  • adjust brightness/contrast.
  • colors -> brightness-contrast.
  • brightness : todo taste (+30.0)
  • contrast : todo taste (-30.0)


Alright, now head over todo the nob_to_pro article on creating Pixar looking eyes todo put this texture todo use. http://en.wikiboks.org/wiki/blender_3d:_nob_to_pro/ creating_pixar-looking_eyes_in_blender here are complete and exploded view renders.





By benjamín schram.
www.blenderart.org.