2. SPHERE is a closed surface all points of which are
equidistant from a fixed point called the center
TOP VIEW
TOP VIEW
P P A B C 5
1
A
A 4
B
2
B 3
C C
3 2
D D 1
5 E
4
P
P
A 1 2 3 4 5 P
B
A
C B
D
C
E
E
Quarter Development
Half Development
FRONT VIEW
FRONT VIEW
Construction by the Polycylindric/Gore method Construction by the Polyconic/Zone method
Title
SAMPLE
Approximate Development of the Spheres
Name Activity No.
Marifa S. Torralba, PhD
Sec. Student No. Date Station No.
3. Instructions
• Sizes of the figures are at your own
discretion
• Apply the alphabet of lines & ink the
figures based on the character of the
lines of the top, front, & lateral area.
• Use leader lines for its dimensions
• Retain the construction lines or do not
erase the pencil sketches totally
• Height of letters = 0.5 cm including that
of the title block
• Use 0.2 pen for all letterings
Prepared by: Marifa Torralba,PhD
4. SPHERE
• closed surface all points of
which are equidistant from a
fixed point called the center
• a radius of the sphere is a line
segment from the center to
any point on the its surface
• a diameter of the sphere is a
line segment whose endpoints
are on the surface that passes
through its center
Prepared by MARIFA S TORRALBA, PhD
5. TOP VIEW
Construction by the Polycylindric/Gore method- quarter development
1. Draw concentric circles in the top (letters) – lines in front
are diameters of these circles
2. divide a quadrant to equal central angles
3. measure arcs 1-2, 2-3, 3-4, 4-5 and draw line at the midpt
4. measure circumferential arc
from great circle (E )to the nxt
P 5 circle in the front view ( D )
5. measure the chord
P of circle D in top
A
6. Repeat steps 4 and 5 until P
4
B A 7. Trace a curve at each
endpoints to form a gore
C 3
D B
8. Using the developed gore
E 2
1 as template, lay out other
C gores to complete the
D
approximate development
P of the sphere
A
B
1 2 3 4 5
C
D
E
FRONT VIEW Prepared by: MARIFA S. TORRALBA, PhD
6. TOP VIEW Construction by the Polyconic/Zone method
1. Draw circle A and draw chord in the front view
2. With P as vertex/pivot, draw arc whose radius = chord
3. Divide one quarter of the sphere to equal sectors
4. Measure arc in A (top) & lay it off in arc (16 parts)
5. Draw line tangent to the sphere at circle A (front)
6. With that line tangent as radius,
draw the arc tangent to arc
P A B C 5 7. Draw circle B
8. In the front view, measure
line tangent + arc bet. A& B.
This becomes the
Radius of another arc
4
9. Measure arc in B (top)
& lay it off in arc (16 parts)
3 10. Repeat step 5 to finsih
half the sphere
2 development
1
P
P
A
B
C
E
FRONT VIEW Prepared by: MARIFA S. TORRALBA, PhD
