Plotting a coarse-grained model of (part of) a protein with PLPlot. This library apparently doesn't feature interactive rotation capabilities (version 5.9.7).

gistfile1.c

/* gcc -Wall -std=c99 plplotline3.c -o plplotline3 -lplplotd */

#include <stddef.h>
#include <plplot/plplot.h>

int main(void)
{
        const size_t num_atoms = 10;
        const double positions[][3] = {{ 13.935, 18.529, 29.843 }, { 13.088, 19.661, 26.283 }, { 12.726, 17.033, 23.612 }, { 12.179, 17.659, 19.887 }, { 10.253, 15.79, 17.221 }, { 11.082, 16.103, 13.475 }, { 8.009, 15.163, 11.389 }, { 8.628, 13.975, 7.913 }, { 5.213, 12.642, 6.966 }, { 3.589, 12.601, 3.497 }};

        plsdev("wxwidgets");
        plinit();
        PLFLT x[num_atoms], y[num_atoms], z[num_atoms];
        for (int i = 0; i < num_atoms; i++) {
                x[i] = positions[i][0];
                y[i] = positions[i][1];
                z[i] = positions[i][2];
        }
        plenv(-50, 50, -50, 50, 1, 0);
        plw3d(10, 10, 30, -20, 20, -20, 20, -20, 20, 0, 0);
        plline3(num_atoms, (PLFLT *) &x, (PLFLT *) &y, (PLFLT *) &z);
        plend();

        return 0;
}