Sculpt Texture Export Script for the GIMP

A simple GIMP plug-in allows a sculpt texture (or any texture) to be converted into a mesh and saved as Wavefront OBJ model, for upload into your favorite 3D modelling tool for previewing. The following Scheme script can be copied to a file and saved in the GIMP "scripts" directory (e.g. on Windows XP, "C:\Documents and Settings\username\.gimp-2.2\scripts\sculptie.scm" or "C:\Program Files\GIMP-2.0\share\gimp\2.0\scripts\sculptie.scm"):

(define (script-fu-exp-sculptie inImage inDrawable inFilename)
  (define (putv x y z f) 
      (let* ((buf (string-append "v " 
                                 (number->string x) " " 
                                 (number->string y) " " 
                                 (number->string z) "\n")))
      (puts buf f)
      )
  )
  (define (v-num-str row col width) (number->string (+ (* row width) col 1)))
  (define (decode x) (if (>= x 0) x (+ 256 x)))
  (let*
    (
    (obj-file (fopen inFilename "w+"))
    (iwidth (car (gimp-drawable-width inDrawable)))
    (iheight (car (gimp-drawable-height inDrawable)))
    (row 0)
    )
    (verbose 2)
    (while (< row iheight)
        (let* ((col 0))
           (while (< col iwidth)
             (let* 
               (
                 (pixel (cadr (gimp-drawable-get-pixel inDrawable col row)))
                 (x (/ (decode (aref pixel 0)) 255.0))
                 (y (/ (decode (aref pixel 1)) 255.0))
                 (z (/ (decode (aref pixel 2)) 255.0))
               )
               (putv x y z obj-file)
             )
             (set! col (+ col 1))
           ) 
        )
        (set! row (+ row 1))
    )
    (set! row 0)
    (while (< row (- iheight 1))
        (let* ((col 0))
           (while (< col iwidth)
             (writes obj-file (string-append "f " 
                   (v-num-str row col iwidth) " " 
                   (v-num-str row  (fmod (+ col 1) iwidth) iwidth) " "
                   (v-num-str (+ row 1) (fmod (+ col 1) iwidth)  iwidth) " "
                   (v-num-str (+ row 1) col iwidth) "\n"))
             (set! col (+ col 1))
           ) 
        )
        (set! row (+ row 1))
    )
    (verbose 0)
    (fclose obj-file)
  )
)

        (script-fu-register
          "script-fu-exp-sculptie"                  ;func name
          "Export Sculptie"                         ;menu label
          "Exports the current image layer as a wavefront\
            obj file."              ;description
          "Kris Kovacs"                             ;author
          "copyright 2007, Kris Kovacs"             ;copyright notice
          "May 17, 2007"                            ;date created
          "RGB*"
          SF-IMAGE "Input Image" 0                  ;image type that the script works on
          SF-DRAWABLE "Input Drawable" 0              ;
          SF-FILENAME      "Output File:"        "tmp.obj" ;a string variable
        )
(script-fu-menu-register "script-fu-exp-sculptie" _"<Image>/Script-Fu/SecondLife")

Restart the GIMP after creating the file (or refresh the scripts with Xtns->Script-Fu->Refresh Scripts from the Tools window). A new menu item will appear in the Image window (Script-Fu->SecondLife->Export Sculptie). The script will prompt the user for a filename, and then will export the image as a mesh which can be uploaded into a 3D modelling tool.

Note that the script does not close off the top and bottom seams of the model the way SL does. Other than that the model will look very similar in a 3D tool as it does in SL.