渐近线：为什么距离相机越近的物体就越小

Question

在下面的例子中，你可以看到最靠近相机的原子实际上比其他原子小，尽管事实应该是相反的。不是吗？

这里是 MWE：

size(700);
import solids;
import texcolors;
import three;

currentprojection=orthographic (
camera=(8,4,4),
up=(0,0,1),
target=(2,2,2),
zoom=1.0
);

// save predefined 2D orientation vectors
pair NN=N;
pair SS=S;
pair EE=E;
pair WW=W;

//%Atom positions

triple Atom1 = (-1.1547, -2., 3.26599);
triple Atom2 = (-1.1547, 2., 3.26599);
triple Atom3 = (2.3094, 0., 3.26599);
triple Atom4 = (0,0,0);

triple[] atoms={
    Atom1,Atom2,Atom3,Atom4,
};

draw((1.3094,0,2.26599)--(3.3094,0,4.26599),(7bp)+green,Arrow3(size=30bp));

real cylR=0.062;

material baseM = material(gray(0.5), black, gray(0.6), black);

void Connect(guide3 g){
    draw(surface(
        cylinder(
            point(g,0),cylR,arclength(g),point(g,1)-point(g,0)
        )),baseM
    );
}

//%connections from Atom1 to all others
Connect(Atom1--Atom2);
Connect(Atom1--Atom3);
Connect(Atom1--Atom4);


//%connections from Atom2 to Atom2+n
Connect(Atom2--Atom3);
Connect(Atom2--Atom4);


//%connections from Atom3 to Atom4
Connect(Atom3--Atom4);


material m  = material(gray(0.5), black, RoyalBlue, black);
// material m2 = material(

void drawSpheres(triple[] C, real R, pen p=currentpen){
    for(int i=0;i<C.length;++i){
        draw(surface(sphere(C[i],R)),m);
    }
}


 drawSpheres(atoms,0.5,RoyalBlue);

Answer 1

它们实际上大小相同。由于视觉错觉，距离较近的物体看起来较小。你的大脑“假设”它较小，因为它距离较近，但它在你的视野中占据相同的角度。

将“正交”替换为“透视”，使近处的更大。