DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.18733#0081
[ 6o }
this method serves for an octagon alfb ; and is the
readied way to : epresent circles within others.
No. III. Supposing these examples sufficient to ex-
pc I the manner of treating solid bodies, &c. we proceed
now to (hew the nature of other objects. It has already
been observed in Lecture II, that all rotatory objects
form a circle a their circumference, of which the hinee
O
Is the center : on this principle are the doors in this ex-
ample put into perspective. Fig. i. C is the centre, H L
the horizontal line ; the breadth of the door is marked on
the ground line, as A B ; and A D is the depth it must
be in the room. Draw D H, cutting AC in E ;
draw from E, a line parallel to the ground line, as E F;
which is cut by B C in F, and determines the width os
the door at that part (if half open) ; F ruled to H will
give e for the edge of the door, if supposed shut: the se-
micircle on the ssoor is formed by the ordinary methods.
From the bottom of the door E, to the circumference
of the circle, gives the sstuation of the door : the same
line continued to HL gives its vanishing point, as at
I: perpendiculars from the bottom of the door, and
its edge, are cut by a line from I, to determine its
height. In Fig. 2. the door is seen open somewhat
disferently : the same process gives K for its vanishing
point; as is clear by the sigure.
No. IV. Is a representation of a trap-door in the
ssoor : A B its breadth ; which os course is the front
of the aperture. The door C, and its hinge D, are
found exactly as the same parts in the foregoing figures j
g is one vanishing point for the quarter of a circle, cor-
responding to .the square A D e f. If this figure, or
those of No. 3, are turned, and viewed Tideways, they
mutually illu(Irate each other-
No. V-
this method serves for an octagon alfb ; and is the
readied way to : epresent circles within others.
No. III. Supposing these examples sufficient to ex-
pc I the manner of treating solid bodies, &c. we proceed
now to (hew the nature of other objects. It has already
been observed in Lecture II, that all rotatory objects
form a circle a their circumference, of which the hinee
O
Is the center : on this principle are the doors in this ex-
ample put into perspective. Fig. i. C is the centre, H L
the horizontal line ; the breadth of the door is marked on
the ground line, as A B ; and A D is the depth it must
be in the room. Draw D H, cutting AC in E ;
draw from E, a line parallel to the ground line, as E F;
which is cut by B C in F, and determines the width os
the door at that part (if half open) ; F ruled to H will
give e for the edge of the door, if supposed shut: the se-
micircle on the ssoor is formed by the ordinary methods.
From the bottom of the door E, to the circumference
of the circle, gives the sstuation of the door : the same
line continued to HL gives its vanishing point, as at
I: perpendiculars from the bottom of the door, and
its edge, are cut by a line from I, to determine its
height. In Fig. 2. the door is seen open somewhat
disferently : the same process gives K for its vanishing
point; as is clear by the sigure.
No. IV. Is a representation of a trap-door in the
ssoor : A B its breadth ; which os course is the front
of the aperture. The door C, and its hinge D, are
found exactly as the same parts in the foregoing figures j
g is one vanishing point for the quarter of a circle, cor-
responding to .the square A D e f. If this figure, or
those of No. 3, are turned, and viewed Tideways, they
mutually illu(Irate each other-
No. V-