Hi There,

I have some megapov scenes that used the I_dat3d function  as below 

function{"data_3D_1", <1> library "i_dat3d" ........ }

I can't find anything in the docs about this function.

Does anyone know how/if I can convert these scene files ?

Cheers
Rob

On Sun, 9 Sep 2001 22:43:31 +0200, sme### [at] skynetbe
(smellenbergh) wrote:

>
>Here are some hints to convert syntax of MegaPov isosurface to 3.5 
>
>* braces {} are required with functions
>  "function x+y"
>should be
>  "function {x+y}"
>
>
>* parameters of a declared function must be specified when called
>  #declare FUNC = function {x+y+z}
>  isosurface { function {FUNC} }
>should be
>  isosurface { function {FUNC(x,y,z)} }
>
>
>* using internal functions (See 7.7 functions.inc)
>  all internal functions are included in the functions.inc and start
>with
>"f_xxx". Parameters are set between ( ) braces and begin with the x,y,z
>parameters)
>   So, MegaPov's "sphere",<0.8> 
>becomes 
>  #include "functions.inc"
>  f_sphere(x,y,z,0.8)
>or, when declaring the function directly, without using the include
>file:
>  #declare MySphere = function { internal(61) }
>  isosurface{ function{ MySphere(x,y,z,0.8) } }
>
>
>* noise3d
>  in 3.5 noise3d is treated as an internal function: use the
>function.inc and
>  f_noise3d(x*4,y*4,z*4)/5
>Note that the noise uses pov's noise generator set in the global
>settings:
>global_settings{
>  noise_generator 1 //old 3.1g plateaud noise
>  noise_generator 2 //MegaPov 0.5 noise
>  noise_generator 3 //New 3.5 perlin noise
>}
>...or use
>  f_noise_generator(x,y,z, P0)
>    * P0 : Noise generator number
>
>*The func_ names have been renamed
>  func_0  >  f_ellipsoid
>  func_1  >  f_blob
>  func_2  >  f_flange_cover
>  func_2b  >  f_blob2
>  func_3  >  f_cross_ellipsoids
>  func_4  >  f_isect_ellipsoids
>  func_5  >  f_spikes
>  func_9  >  f_poly4
>  func_10  >  f_spikes_2d
>  func_11  >  f_quantum
>  func_12  >  f_helical_torus
>  func_13  >  f_comma
>  func_16  >  f_polytubes
>And the duplicate functions have been removed
>  helix1 / func_6  >  f_helix1
>  helix2 / func_7  >  f_helix2
>  spiral / func_8  >  f_spiral
>  mesh1 / func_14  >  f_mesh1
>
>
>
>* using function { pigments } in isosurfaces
>  the pigment must be declared. When calling it, the dot notation must
>be used: FUNC(x,y,z).x
>This allows to use the channels of the color vector in a controlled way
>Allowed are:
>  .x .u .red, .y .v .green, .z .t .blue, .filter, .transmit for the
>separate channels
>  .gray or .grey for the gray value of the color vector
>  .hf for the height_field value of the color vector (this was the
>method used in MegaPov)
>  #declare Granny = function{
>    pigment{
>      granite scale 3
>      color_map { [0 rgb 0] [1 rgb 1] }
>    }
>  }
>  isosurface{function{f_sphere(x,y,z,1)+Granny(x,y,z).hf*0.2}}
>
>
>* sign is no longer used in 3.5 isosurface
>to switch inside/outside, turn the whole function negative:
>  #declare Landscape = function { f_ridged_mf(x,y,z,1,2,10,1.1,2) }
>  isosurface{function{ Landscape(x,0,z)-y }
>becomes
>  isosurface{function{ -(Landscape(x,0,z)-y) }
>
>
>* sqr and cub no longer supported
>  use ^2 and ^3 ,or pow(A,2) and pow(A,3)
>
>
>* sqrt x^y and ln are used in the mathematical form in 3.5
>  Isosurface     MegaPov internal   3.5 internal
>  ----------     ---------------    ------------
>  sqrt(x)     =  sqrt(abs(x))       =sqrt(x)
>  x^y         =  abs(x)^y           =x^y
>  ln(x)       =  ln(abs(x))         =ln(x)
>So, these MegaPov functions might need to be written as they have been
>used internally in MegaPov to get the same results in 3.5
>
>
>* if(A,B,C)
>  has been replaced by select (A,C,B)
>MegaPov
>  isosurface {function {if(-x, abs(x)+abs(y)-0.5, sqrt(z^2+y^2)-0.5)}
>becomes in 3.5
>  isosurface{function{select(-x, sqrt(z^2+y^2)-0.5, abs(x)+abs(y)-0.5)}
>
>
>* method 1 and method 2
>  keywords no longer used in 3.5: a method 2-ish method is standard
>
>
>* eval
>  eval becomes evaluate and *requires* 3 parameters without the vector
>braces: evaluate A,B,0.99 which is the same as MegaPov's eval <A,B,0.99>
>
>
>I think these are the main changes, but I probably forgot some :-)
>
>

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