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Revision 1.3 by greg, Mon May 15 14:42:30 1995 UTC vs.
Revision 1.17 by greg, Tue Mar 18 12:57:07 1997 UTC

# Line 5 | Line 5
5   .vs 12
6   .nr PD .5v
7   .ds LF MGF
8 < .ds RF Version 1.0
9 < .DA May 1995
8 > .ds RF Version 1.1
9 > .\" !Remember to update date on each modification!
10 > .DA February 1996
11   .TL
12   The Materials and Geometry Format
13   .AU
# Line 42 | Line 43 | and sample scenes and objects at the web site,
43   "http://radsite.lbl.gov/mgf/HOME.html".
44   .RE
45   .LP
46 < The standard parser provides both immediate and a long-term
46 > The standard parser provides both immediate and long-term
47   benefits, since it presents a programming interface that is more
48   stable even than the language itself.
49   Unlike AutoCAD DXF and other de facto standards, a change to the
# Line 232 | Line 233 | p      x y z   set point position for current vertex
233   n       dx dy dz        set surface normal for current vertex
234   _       _       _
235   f       v1 v2 v3 ...    polygon using current material, spec. vertices
236 + fh      v1 v2 v3 - ...  face with explicit holes
237   sph     vc radius       sphere
238   cyl     v1 radius v2    truncated right cylinder (open-ended)
239   cone    v1 rad1 v2 rad2 truncated right cone (open-ended)
# Line 277 | Line 279 | Context        Cntl. Entity    Default Value   Field Entities  Affe
279   =       =       =       =       =
280   Object  o       -       -       -
281   Transform       xf      -       -       T{
282 < f, sph, cyl, cone,
282 > f, fh, sph, cyl, cone,
283   ring, torus, prism
284   T}
285   Material        m       2-sided black   T{
286   sides, rd, td,
287 < ed, rs, ts
287 > ed, rs, ts, ir
288   T}      T{
289 < f, sph, cyl, cone,
289 > f, fh, sph, cyl, cone,
290   ring, torus, prism
291   T}
292   Color   c       neutral grey    T{
# Line 296 | Line 298 | Vertex v       T{
298   (0,0,0),
299   no normal
300   T}      p, n    T{
301 < f, sph, cyl, cone,
301 > f, fh, sph, cyl, cone,
302   ring, torus, prism
303   T}
304   .TE
# Line 746 | Line 748 | o door
748          o
749   o
750  
749 –        i cubfurn.inc -mx -t 405 133.5 0
750 – o
751 –
751   # Six file cabinets (36" wide each)
752   # ("filecab.inc" was given as an earlier example in Section 1.2)
753   o filecab.x
# Line 818 | Line 817 | Geometry
817   .TS
818   lw(.75i) lw(1.75i) lw(3i).
819   f       v1 v2 v3 ...    polygon using current material, spec. vertices
820 + fh      v1 v2 v3 - ...  face with explicit holes
821   sph     vc radius       sphere
822   cyl     v1 radius v2    truncated right cylinder (open-ended)
823   cone    v1 rad1 v2 rad2 truncated right cone (open-ended)
# Line 1269 | Line 1269 | corresponds to the measurement at
1269   Values in between are separated by
1270   .I "(l_max-l_min)/(N-1)"
1271   nanometers.
1272 < All values must be non-negative, and the spectrum outside of the
1272 > All values should be non-negative unless defining a component for
1273 > complementary color mixing, and the spectrum outside of the
1274   specified range is assumed to be zero.
1275   (The visible range is 380 to 780 nm.)\0
1276   The actual units and scale of the measurements do not matter,
# Line 1676 | Line 1677 | EXAMPLE
1677   # A 100-watt incandescent bulb (1600 lumens) modeled as a sphere
1678   m
1679          c
1680 <        cct 3000
1680 >                cct 3000
1681          ed 87712
1682   v cent =
1683          p 0 0 0
# Line 2070 | Line 2071 | when normals are used.
2071   Also, specified normals should point in the general direction of the
2072   surface for best results.
2073   .LP
2074 < There is no explicit representation of holes in MGF.  A hole must be
2075 < represented implicitly by connecting vertices to form "seams."  For
2074 > There is no explicit representation of holes in this entity, but see
2075 > the
2076 > .UL fh
2077 > entity for an alternative specification.
2078 > .LP
2079 > A hole may be represented implicitly in a face entity
2080 > by connecting vertices to form "seams."
2081 > For
2082   example, a wall with a window in it might look as shown in Figure 1.
2083   In many systems, the wall itself would be represented with the first
2084   list of vertices, (v1,v2,v3,v4) and the hole associated with that
2085 < wall as a second set of vertices (v5,v6,v7,v8).  In MGF, we must
2085 > wall as a second set of vertices (v5,v6,v7,v8).
2086 > Using the face entity, we must
2087   give the whole thing as a single polygon, connecting the vertices so
2088   as to create a "seam," as shown in Figure 2.
2089 < This could be written in MGF as "f v1 v2 v3 v4 v5 v6 v7 v8 v5 v4".
2089 > This could be written as "f v1 v2 v3 v4 v5 v6 v7 v8 v5 v4".
2090   .LP
2091   It is very important that the order of the hole be opposite to the
2092   order of the outer perimeter, otherwise the polygon will be
# Line 2127 | Line 2135 | SEE ALSO
2135   .LP
2136   .UL cone,
2137   .UL cyl,
2138 + .UL fh,
2139   .UL m,
2140   .UL prism,
2141   .UL ring,
2142   .UL sph,
2143   .UL torus,
2144   .UL v
2145 + .ds RH FH
2146 + .bp
2147 + .SH
2148 + NAME
2149 + .LP
2150 + fh - create a polygonal face with explicit holes
2151 + .SH
2152 + SYNOPSIS
2153 + .LP
2154 + .B fh
2155 + .I "p1 p2 ... - h1.1 h1.2 ... - h2.1 h2.2 ..."
2156 + .SH
2157 + DESCRIPTION
2158 + .LP
2159 + Create a polygonal face with optional holes made of the current material.
2160 + The first contour is the outer perimeter, with vertices given in
2161 + counter-clockwise order as seen from the front side (the same as the
2162 + .UL f
2163 + entity).
2164 + A hole is indicated by a hyphen ('-') followed by the hole's
2165 + vertices, given in clockwise order as seen from the front side.
2166 + Multiple hole contours are separated by additional hyphens.
2167 + There must be at least three vertices for each contour, and the
2168 + last vertex is implicitly connected to the first.
2169 + If any vertex is undefined, an error will result.
2170 + .LP
2171 + If any vertices have associated surface normals, they will be used
2172 + instead of the average plane normal, though it is safest to specify
2173 + either all normals or no normals, and to stick with triangles
2174 + when normals are used.
2175 + Also, specified normals should point in the general direction of the
2176 + surface for best results.
2177 + .SH
2178 + EXAMPLE
2179 + .DS
2180 + # Make a wall with a window using an explicit hole.
2181 + # (See Figures 1 and 2.)
2182 + fh v1 v2 v3 v4 - v5 v6 v7 v8
2183 + .DE
2184 + .SH
2185 + SEE ALSO
2186 + .LP
2187 + .UL cone,
2188 + .UL cyl,
2189 + .UL f,
2190 + .UL m,
2191 + .UL prism,
2192 + .UL ring,
2193 + .UL sph,
2194 + .UL torus,
2195 + .UL v
2196   .ds RH SPH
2197   .bp
2198   .SH
# Line 2228 | Line 2288 | o stylus
2288                  p 0 0 .005
2289          v vend =
2290                  p 0 0 .05
2291 <        cyl vtip1 .0015
2291 >        cyl vtip1 .0015 vend
2292          sph vend .0015
2293          cone vtip0 0 vtip1 .0015
2294   o
# Line 2390 | Line 2450 | ring - create a circular ring with inner and outer rad
2450   .SH
2451   SYNOPSIS
2452   .LP
2453 < .B cyl
2453 > .B ring
2454   .I "vc rmin rmax"
2455   .SH
2456   DESCRIPTION
# Line 2503 | Line 2563 | SEE ALSO
2563   .NH
2564   MGF Translators
2565   .LP
2566 < Initially, there are four translators for MGF data, but only
2567 < one of these is distributed with the MGF parser itself,
2568 < .I mgfilt.
2566 > Initially, there are six translators for MGF data, and
2567 > three of these are distributed with the MGF parser itself,
2568 > .I mgfilt,
2569 > .I mgf2inv
2570 > and
2571 > .I 3ds2mgf.
2572   Two of the other translators,
2573   .I mgf2rad
2574   and
# Line 2518 | Line 2581 | package\(dg.
2581   nestor.epfl.ch, or by WWW from
2582   "http://radsite.lbl.gov/radiance/HOME.html"
2583   .FE
2584 < A third translator,
2584 > The sixth translator,
2585   .I mgf2meta,
2586   converts to a 2-dimensional line plot, and is also
2587   distributed with Radiance.
# Line 2535 | Line 2598 | unwanted entities.
2598   In future releases of MGF, this utility will also be handy for
2599   taking new entities and producing older versions of MGF for
2600   translators that have not yet been updated properly.
2601 + .LP
2602 + Mgf2inv converts from MGF to Inventor or VRML format.
2603 + Some information is lost, because these formats do not support
2604 + physical light sources or materials.
2605 + .LP
2606 + 3ds2mgf converts from 3D Studio binary format to MGF.
2607 + Care must be taken to correct for errors in the material descriptions,
2608 + since 3D Studio is completely non-physical.
2609   .ds LH Translators
2610   .ds RH MGFILT
2611   .bp
# Line 2569 | Line 2640 | In the first form, a single integer is given for the
2640   of MGF that is to be produced.
2641   Since MGF is in its first major release, this is not yet a useful
2642   form, but it will be when the second major release comes out.
2643 + This has the necessary side-effect of expanding all included files.
2644 + (See the
2645 + .UL i
2646 + entity.)\0
2647   .LP
2648   In the second form,
2649   .I mgfilt
# Line 2593 | Line 2668 | mgfilt f,v,p,xf input.mgf > flatpoly.mgf
2668   .SH
2669   SEE ALSO
2670   .LP
2671 < mgf2rad, rad2mgf
2671 > i, mgf2inv, mgf2rad, rad2mgf
2672 > .ds RH MGF2INV
2673 > .bp
2674 > .SH
2675 > NAME
2676 > .LP
2677 > mgf2inv - convert from MGF to Inventor or VRML format
2678 > .SH
2679 > SYNOPSIS
2680 > .LP
2681 > .B mgf2inv
2682 > [
2683 > .B "-1|-2|-vrml"
2684 > ]
2685 > [
2686 > .B input ..
2687 > ]
2688 > .SH
2689 > DESCRIPTION
2690 > .LP
2691 > .I Mgf2inv
2692 > takes one or more MGF input files and converts it to
2693 > Inventor or VRML format.
2694 > If the
2695 > .I \-1
2696 > option is used, then Inventor 1.0 ASCII output is produced.
2697 > If the
2698 > .I \-2
2699 > option is used, then Inventor 2.0 ASCII output is produced.
2700 > (This is the default.)\0
2701 > If the
2702 > .I \-vrml
2703 > option is used, then VRML 1.0 ASCII output is produced.
2704 > .LP
2705 > This converter does not work properly for light sources, since
2706 > the output formats do not support IES-type luminaires with recorded
2707 > distributions.
2708 > Also, some material information may be lost because Inventor lacks
2709 > a physically valid reflectance model.
2710 > .SH
2711 > EXAMPLES
2712 > .LP
2713 > To take an MGF file and convert it to VRML format:
2714 > .IP
2715 > mgf2inv -vrml myscene.mgf > myscene.iv
2716 > .SH
2717 > SEE ALSO
2718 > .LP
2719 > mgf2rad(1), mgfilt(1), 3ds2mgf(1), rad2mgf(1)
2720 > .ds RH 3DS2MGF
2721 > .bp
2722 > .SH
2723 > NAME
2724 > .LP
2725 > 3ds2mgf - convert 3D Studio binary file to Materials and Geometry Format
2726 > .SH
2727 > SYNOPSIS
2728 > .LP
2729 > .B 3ds2mgf
2730 > .B input
2731 > [
2732 > .B output
2733 > ]
2734 > [
2735 > .B -lMatlib
2736 > ][
2737 > .B -xObjname
2738 > ][
2739 > .B -sAngle
2740 > ][
2741 > .B -aAnimfile
2742 > ][
2743 > .B -fN
2744 > ]
2745 > .SH
2746 > DESCRIPTION
2747 > .LP
2748 > .I 3ds2mgf
2749 > converts a 3D Studio binary scene description
2750 > to the Materials and Geometry Format (MGF).
2751 > If no output file name is given, the input root name
2752 > will be taken as the output root, and an "mgf" extension
2753 > will be added.
2754 > This file will contain any light sources and materials, and an include
2755 > statement for a similarly named file ending in "inc", which will contain
2756 > the MGF geometry of all the translated 3DS meshes.
2757 > .LP
2758 > The MGF material names and properties
2759 > for the surfaces will be those assigned in 3D Studio,
2760 > unless they are named in one or more MGF material libraries given in a
2761 > .I -l
2762 > option.
2763 > .LP
2764 > The
2765 > .I -x
2766 > option may be used to exclude a named object from the output.
2767 > .LP
2768 > The
2769 > .I -s
2770 > option may be used to adjust automatic mesh smoothing such that adjacent
2771 > triangle faces with less than the given angle between them (in degrees)
2772 > will be smoothed.
2773 > A value of zero turns smoothing off.
2774 > The default value is 60 degrees.
2775 > .LP
2776 > The
2777 > .I -a
2778 > option may be used to specify a 3D Studio animation file, and together with the
2779 > .I -f
2780 > option,
2781 > .I 3ds2mgf
2782 > will generate a scene description for the specified frame.
2783 > .LP
2784 > Note that there are no spaces between the options and their arguments.
2785 > .SH
2786 > LIMITATIONS
2787 > .LP
2788 > Obviously, since 3D Studio has no notion of physical materials, the
2789 > translation to MGF material descriptions is very ad hoc, and it will
2790 > usually be necessary to edit the materials and light sources in
2791 > the output file or replace materials with proper entries from a material
2792 > library using the
2793 > .I -l
2794 > option.
2795 > .LP
2796 > With smoothing turned on (i.e., a non-zero value for the
2797 > .I -s
2798 > option), vertices in the MGF output will not be linked in a proper
2799 > mesh for each object.
2800 > This is due to the way the automatic smoothing code was originally
2801 > written, and is too difficult to repair.
2802 > If a good mesh is needed, then smoothing must be turned off.
2803 > .SH
2804 > EXAMPLES
2805 > .LP
2806 > To convert a 3D Studio robot model to MGF without smoothing.
2807 > (Output will be put into "robot.mgf" and "robot.inc".)
2808 > .IP
2809 > 3ds2mgf robot.3ds -s0
2810 > .LP
2811 > To convert a DC10 jet model to MGF using a hand-created material library:
2812 > .IP
2813 > 3ds2mgf dc10.3ds -ldc10mat.mgf
2814 > .SH
2815 > AUTHORS
2816 > .LP
2817 > Steve Anger, Jeff Bowermaster and Greg Ward
2818 > .br
2819 > Extended from 3ds2pov 1.8.
2820 > .SH
2821 > SEE ALSO
2822 > .LP
2823 > mgf2inv(1), mgf2meta(1), mgf2rad(1)
2824   .ds RH MGF2RAD
2825   .bp
2826   .SH
# Line 3123 | Line 3350 | following:
3350   #define MG_E_CMIX               4               /* cmix */
3351   #define MG_E_CSPEC              5               /* cspec        */
3352   #define MG_E_CXY                6               /* cxy          */
3353 < #define MG_E_CYL                7               /* cyl  */
3353 > #define MG_E_CYL                7               /* cyl          */
3354   #define MG_E_ED         8               /* ed           */
3355   #define MG_E_FACE               9               /* f            */
3356   #define MG_E_INCLUDE    10              /* i            */
# Line 3275 | Line 3502 | and return one of the non-zero values from "parser.h"
3502   #define MG_EMEM         8               /* out of memory */
3503   #define MG_ESEEK                9               /* file seek error */
3504   #define MG_EBADMAT      10              /* bad material specification */
3505 + #define MG_ELINE                11              /* input line too long */
3506 + #define MG_ECNTXT               12              /* unmatched context close */
3507  
3508 < #define MG_NERRS        11
3508 > #define MG_NERRS                13
3509   .DE
3510   If it is inappropriate to send output to standard error, the calling
3511   program should use the routines listed under
# Line 3290 | Line 3519 | listed above in the native country's language.
3519   .SH
3520   SEE ALSO
3521   .LP
3522 < mg_fgetpos, mg_handle, mg_init
3522 > mg_fgetpos, mg_handle, mg_init, mg_open
3523   .ds RH MG_OPEN
3524   .bp
3525   .SH
# Line 3360 | Line 3589 | The
3589   function reads the next input line from the current file,
3590   returning the number of characters in the line, or zero if the
3591   end of file is reached or there is a file error.
3592 < The function skips over escaped newlines, and keeps track of the
3592 > If the value returned equals MG_MAXLINE-1,
3593 > then the input line was too long, and you
3594 > should return an MG_ELINE error.
3595 > The function keeps track of the
3596   line number in the current file context
3597   .I mg_file,
3598   which also contains the line that was read.
# Line 3696 | Line 3928 | To link identical vertices, one must also check that t
3928   transform has not changed, which is uniquely identified by the
3929   global
3930   .I xf_context->xid
3931 < variable, but only if one is using the parser libraries transform
3931 > variable, but only if one is using the parser library's transform
3932   handler.
3933   (See the
3934   .I xf_handler
# Line 4427 | Line 4659 | familiar Gaussian model of MGF.
4659   The hardest part is translating the specular power to a roughness value.
4660   For this, we recommend the following approximation:
4661   .IP
4662 < roughness = 0.6/sqrt(specular_power)
4662 > roughness = sqrt(2/specular_power)
4663   .LP
4664   It is not a perfect correlation, but it is about as close as one can get.
4665   .NH 3
# Line 4489 | Line 4721 | and adopt the following code to convert between CIE an
4721   #define  CIE_y_w                0.3333
4722   #endif
4723  
4724 < #define CIE_D           (       CIE_x_r*(CIE_y_g - CIE_y_b) + \\\\
4725 <                                CIE_x_g*(CIE_y_b - CIE_y_r) + \\\\
4724 > #define CIE_D           (       CIE_x_r*(CIE_y_g - CIE_y_b) + \\
4725 >                                CIE_x_g*(CIE_y_b - CIE_y_r) + \\
4726                                  CIE_x_b*(CIE_y_r - CIE_y_g)     )
4727 < #define CIE_C_rD        ( (1./CIE_y_w) * \\\\
4728 <                                ( CIE_x_w*(CIE_y_g - CIE_y_b) - \\\\
4729 <                                  CIE_y_w*(CIE_x_g - CIE_x_b) + \\\\
4727 > #define CIE_C_rD        ( (1./CIE_y_w) * \\
4728 >                                ( CIE_x_w*(CIE_y_g - CIE_y_b) - \\
4729 >                                  CIE_y_w*(CIE_x_g - CIE_x_b) + \\
4730                                    CIE_x_g*CIE_y_b - CIE_x_b*CIE_y_g     ) )
4731 < #define CIE_C_gD        ( (1./CIE_y_w) * \\\\
4732 <                                ( CIE_x_w*(CIE_y_b - CIE_y_r) - \\\\
4733 <                                  CIE_y_w*(CIE_x_b - CIE_x_r) - \\\\
4731 > #define CIE_C_gD        ( (1./CIE_y_w) * \\
4732 >                                ( CIE_x_w*(CIE_y_b - CIE_y_r) - \\
4733 >                                  CIE_y_w*(CIE_x_b - CIE_x_r) - \\
4734                                    CIE_x_r*CIE_y_b + CIE_x_b*CIE_y_r     ) )
4735 < #define CIE_C_bD        ( (1./CIE_y_w) * \\\\
4736 <                                ( CIE_x_w*(CIE_y_r - CIE_y_g) - \\\\
4737 <                                  CIE_y_w*(CIE_x_r - CIE_x_g) + \\\\
4735 > #define CIE_C_bD        ( (1./CIE_y_w) * \\
4736 >                                ( CIE_x_w*(CIE_y_r - CIE_y_g) - \\
4737 >                                  CIE_y_w*(CIE_x_r - CIE_x_g) + \\
4738                                    CIE_x_r*CIE_y_g - CIE_x_g*CIE_y_r     ) )
4739  
4740   #define CIE_rf          (CIE_y_r*CIE_C_rD/CIE_D)

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