3D scanner

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Quick Questions

Shade in the A or B circle for each question.

1. Which statement describes what a 3D scanner does?

A It captures the shape of a real object as a digital 3D model

B It prints a real object from a digital 3D model

2. How does a 3D scanner build up a model of an object?

A It takes one reading from the centre of the object

B It measures the distance to many points on the surface

3. Which can a 3D scanner use to measure points on a surface?

A Lasers, light patterns or cameras

B Magnets, keys or microphones

4. Is a 3D scanner an input device or an output device?

A Output device, because it produces a solid object

B Input device, because it sends data about an object into the computer

5. How can a scanner capture all sides of an object?

A Scan from several angles or rotate the object

B Scan the front only and let the software guess the rest

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
13D scanner		AA 3D scanner is an input device that captures the shape of an object. Printing a copy is done by a 3D printer, which is an output device.
2point cloud		BAn input device that measures the distance to many points on an object's surface to capture its shape as a digital 3D model
3A scanner uses a laser, light pattern or camera to measure points on the surface of an object		Cfor angle in range(0, 360, 45): scan(angle)
4The object is scanned from several angles or rotated on a turntable so the whole shape is captured		DA 3D scanner needs many readings from many points on the surface, often from several angles, to build an accurate 3D model.
5A 3D scanner is an output device that prints a copy of an object		Elaser.measureDistance(point)
6A 3D scanner takes one reading of an object to build its 3D model		FThe many distance readings from the surface of an object, combined by software to build the 3D model

Definitions

3D scanner

Fill in the Blanks

Complete each line of code by filling in the missing parts.

device ← __________ model ← device.SCAN(object) OUTPUT model

points ← MeasureSurface(object) model ← __________(points)

___ angle ← 0 TO 270 STEP 90 SCAN(object, angle) NEXT angle

model ← SCAN(object) SEND model TO __________

IF pointCount > 0 ____ model ← BuildModel(points) ENDIF

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A model ← []

B FOR angle ← 0 TO 270 STEP 90

C reading ← SCAN(angle)

D model ← reading

E NEXT angle

Question 2

A device ← "3D printer"

B points ← MEASURE(device)

C model ← BUILD(points)

D OUTPUT model

Question 3

A points ← 0

B WHILE points > 100000

C MEASURE_POINT()

D points ← points + 1

E ENDWHILE

Question 4

A scanner ← LASER

B part ← "car part"

C model ← SCAN3D(part)

D SEND model TO SPEAKER

Question 5

A turntable ← ON

B FOR step ← 1 TO 36

C ROTATE(turntable, 100)

D SCAN()

E NEXT step

Answer Key

3D scanner

Section A: Quick Questions

A — It captures the shape of a real object as a digital 3D model

B — It measures the distance to many points on the surface

A — Lasers, light patterns or cameras

B — Input device, because it sends data about an object into the computer

A — Scan from several angles or rotate the object

Section B: Match the Pairs

3D scanner → An input device that measures the distance to many points on an object's surface to capture its shape as a digital 3D model

point cloud → The many distance readings from the surface of an object, combined by software to build the 3D model

A scanner uses a laser, light pattern or camera to measure points on the surface of an object → laser.measureDistance(point)

The object is scanned from several angles or rotated on a turntable so the whole shape is captured → for angle in range(0, 360, 45): scan(angle)

A 3D scanner is an output device that prints a copy of an object → A 3D scanner is an input device that captures the shape of an object. Printing a copy is done by a 3D printer, which is an output device.

A 3D scanner takes one reading of an object to build its 3D model → A 3D scanner needs many readings from many points on the surface, often from several angles, to build an accurate 3D model.

Section C: Definitions

3D scanner — An input device that uses lasers, light patterns or cameras to measure many points on an object's surface and combine them into a digital 3D model of its shape.

Section D: Fill in the Blanks

device ← 3D scanner
model ← device.SCAN(object)
OUTPUT model

points ← MeasureSurface(object)
model ← BuildModel(points)

FOR angle ← 0 TO 270 STEP 90
  SCAN(object, angle)
NEXT angle

model ← SCAN(object)
SEND model TO 3D printer

IF pointCount > 0 THEN
  model ← BuildModel(points)
ENDIF

Section E: Spot the Error

D — This overwrites the model on every loop, so only the last angle is kept. The readings from all angles must be combined, so it should be APPEND(model, reading).

A — A 3D printer is an output device that makes objects. The device that measures a real object and captures its shape is the 3D scanner.

B — points starts at 0, so points > 100000 is false straight away and no points are measured. The condition should be points < 100000 so many readings are taken.

D — A speaker outputs sound and cannot copy an object. To make a copy of the scanned part, the model is sent to a 3D printer.

C — 36 steps of 100 degrees would spin the object far too much and miss detail. Steps of 10 degrees make exactly one full 360 degree turn, so all sides are scanned.