How to create a 3D image using x y z coordinates

Question

I was given code that generates a 2D image using x, y, z coordinates from data, I want to modify this code to create a 3D image instead. (Code source: https://physiology.arizona.edu/people/secomb/netflow )

The code down below creates a 2D image, using the xyz coordinates from the data I would like to modify the code to create a 3D image

For example: Turn this https://www.researchgate.net/figure/A-2D-meshed-model-of-the-flow-network-in-GAMBIT_fig12_266171604

into this https://www.researchgate.net/figure/Single-phase-two-component-flow-in-a-blood-vessel-network-One-dimensional-elements-are_fig4_283761787

Here is the C++ code, I am using it in visual studio 2019

/**********************************************************
picturenetwork.cpp - project network on z = 0 plane
Labels nodes with nodvar and segments with segvar (must be float)
Colors segments according to segvar
Generates a postscript file
Version for NetFlowV1, TWS Oct. 2012
***********************************************************/
#define _CRT_SECURE_NO_DEPRECATE

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "nrutil.h"

void picturenetwork(float *nodvar, float *segvar, const char fname[])
{
    extern int nseg,nnod;
    extern int *segtyp,*ista,*iend;
    extern float *diam,**cnode;
    int k,iseg,inod,ilevel,nlevel = 100;
    float xmin,xmax,ymin,ymax,xs,ys,zs,picfac,red,green,blue,xz,xzmin,xzmax, zzmin, zzmax;
    float diamfac = 1.,zcoord,zbottom,ztop,zmin,zmax;
    FILE *ofp;

//Determine range of x,y,z values
    xmin = 1.e6;
    xmax = -1.e6;
    ymin = 1.e6;
    ymax = -1.e6;
    zmin = 1.e6;
    zmax = -1.e6;
    for(inod=1; inod<=nnod; inod++){
        xmin = FMIN(xmin,cnode[1][inod]);
        xmax = FMAX(xmax,cnode[1][inod]);
        ymin = FMIN(ymin,cnode[2][inod]);
        ymax = FMAX(ymax,cnode[2][inod]);
        zmin = FMIN(zmin,cnode[3][inod]);
        zmax = FMAX(zmax,cnode[3][inod]);
    }
    zmin -= 1.; //make sure everything is included
    zmax += 1.;

    picfac = FMIN(500./(xmax - xmin),700./(ymax - ymin));
    ofp = fopen(fname, "w");

    fprintf(ofp, "%%!PS-Adobe-2.0\n");
    fprintf(ofp, "%%%%Pages: 1\n");
    fprintf(ofp, "%%%%EndComments\n");
    fprintf(ofp, "%%%%Page: 1 1\n");
    fprintf(ofp, "/mx {%g sub %g mul 50 add} def\n",xmin,picfac);
    fprintf(ofp, "/my {%g sub %g mul 50 add} def\n",ymin,picfac);
    fprintf(ofp, "/cf {closepath fill} def\n");
    fprintf(ofp, "/cs {closepath stroke} def\n");
    fprintf(ofp, "/m {moveto} def\n");
    fprintf(ofp, "/n {newpath} def\n");
    fprintf(ofp, "/l {lineto} def\n");
    fprintf(ofp, "/sl {setlinewidth} def\n");
    fprintf(ofp, "/sc {setrgbcolor} def\n");
    fprintf(ofp, "/s {stroke} def\n");
    fprintf(ofp, "/Times-Roman findfont\n");
    fprintf(ofp, "8 scalefont\n");
    fprintf(ofp, "setfont\n");

    fprintf(ofp, "newpath\n");
    fprintf(ofp, "%g mx %g my m\n",xmin,ymin);
    fprintf(ofp, "%g mx %g my l\n",xmax,ymin);
    fprintf(ofp, "%g mx %g my l\n",xmax,ymax);
    fprintf(ofp, "%g mx %g my l\n",xmin,ymax);
    fprintf(ofp, "closepath\n");
    fprintf(ofp, "stroke\n");

    fprintf(ofp, "/Times-Roman findfont\n");
    fprintf(ofp, "4 scalefont\n");
    fprintf(ofp, "setfont\n");

//plot vessels colored according to segvar, in order from bottom to top according to z-coordinate
    xzmin = 1.e6;
    xzmax = -1.e6;
    for(iseg=1; iseg<=nseg; iseg++) if(segtyp[iseg] == 4 || segtyp[iseg] == 5){
        xzmin = FMIN(xzmin,segvar[iseg]);
        xzmax = FMAX(xzmax,segvar[iseg]);
    }
    for(ilevel=1; ilevel<=nlevel; ilevel++){
        zbottom = zmin + (ilevel-1)*(zmax - zmin)/nlevel;
        ztop = zmin + ilevel*(zmax - zmin)/nlevel;
        for(iseg=1; iseg<=nseg; iseg++) if(segtyp[iseg] == 4 || segtyp[iseg] == 5){
            zcoord = (cnode[3][ista[iseg]] + cnode[3][iend[iseg]])/2.;
            if(zcoord >= zbottom && zcoord < ztop){
                if(xzmin != xzmax) xz = (segvar[iseg] - xzmin)/(xzmax - xzmin);
                else xz = 0.75;
                blue = FMIN(FMAX(1.5-4.*fabs(xz-0.25), 0.), 1.);//Set up colors using Matlab 'jet' scheme
                green= FMIN(FMAX(1.5-4.*fabs(xz-0.5), 0.), 1.);
                red  = FMIN(FMAX(1.5-4.*fabs(xz-0.75), 0.), 1.);
                fprintf(ofp,"%f %f %f sc\n",red,green,blue);
                fprintf(ofp,"%g sl\n",picfac*diam[iseg]*diamfac);//line widths scaled up by diamfac
                fprintf(ofp, "%g mx %g my m ", cnode[1][ista[iseg]],cnode[2][ista[iseg]],cnode[3][ista[iseg]]);
                fprintf(ofp, "%g mx %g my l s \n", cnode[1][iend[iseg]],cnode[2][iend[iseg]],cnode[3][iend[iseg]]);
            }
        }
    }

The image created is a .ps file, so far there are no errors. The main issue is the image produced is 2D and not 3D . The image is of vessels of varying colors.

Answer 1

It is impossible to create a 3D model using this code. This code is outputting a .ps file which does not support 3D figures.