2. Summary
• Project introduction
–Overview of project tasks
–Workflow
–Working area
–Basic rules
• Drawing rules
–Single layer
–Multi-layer
•Multi-layer drawing skills for adjoining
buildings
3. Content : from 2D imagery, draw the 3D building structure
using the rooftop as a starting point
Project introduction
• Overview of project tasks
4. labeller checker
errors exist, pushed
back
finish task, submit
Project introduction
• Workflow
errors exist, pushed
back
passed, submit
Judger Final approval
Online system
Labeler’s task: draw images following project requirements; then revise results
based on checkers feedback.
Checker’s task: check labeler’s drawing result, and also add revision comments
The loop will be complete when the task is approved by the Checker.
5. 1 2
4
3
Task area
No
Task area (“assistant grid”)
• Buildings entirely located
in your own task area
must be drawn;
• Buildings partially located
(one pixel or more) in
your task area and any
other region besides
1,2,3,4, must also be
drawn.
• Any buildings partially
located in areas 1, 2, 3, or
4 are not to be drawn;
Project introduction
• Working area
6. • 1. Shape: The geometric shape of building rooftops is a polygon. Usually the
opposite lines are parallel; adjacent lines are perpendicular (ie. residential
houses & industrial buildings). Some buildings might have unique shapes,
such as oval, diamond, or other irregular shapes (ie. shopping malls, office
buildings, high rise apartments).
• 2. Accuracy: Drawings of building rooftops must be accurate within 3 pixels.
Small angles/corners within 3 pixels can be simplified (no matter drawn or
not is acceptable). However, redundant angles/corners are not allowed.
Drawing rules
• Buildings with consistent height (single layer structure): only draw one
layer
• Buildings with inconsistent height (multi-layer structures): draw each layers
by “brother” method (recommended) or “father & son” method.
Project introduction
Basic rules
7. • Basic rules
– 1. Shape: The geometric shape of building rooftops is a
polygon. Usually the opposite lines are parallel; adjacent
lines are perpendicular.
Project introduction
8. • Basic rules
– 2. Accuracy: Drawings of building rooftops must be accurate
within 3 pixels. Small angles within 3 pixels can be simplified (no
matter drawn or not is acceptable). However, drawing non-
existing/redundant angles are not allowed.
Sample 1: Small angles within 3 pixels can be passed (no matter drawn or not).
Project introduction
9. • Basic rules
– 2. Accuracy: Drawings of building rooftops must be accurate
within 3 pixels. Small angles within 3 pixels can be simplified (no
matter drawn or not is acceptable). However, redundant angles
are not allowed.
Sample 2: Small angles within 3 pixels can be passed (no matter drawn or not).
Project introduction
10. • Basic rules
– 2. Accuracy: Drawings of building rooftops
must be accurate within 3 pixels. Small angles
within 3 pixels can be simplified (no matter
drawn or not is acceptable). However,
redundant angles are not allowed.
Sample 3: Redundant angles are not allowed
Project introduction
11. Drawing rules
single layer multi layer
• There are two types of buildings by using different drawing methods:
1. Single layer buildings : Single layer building has consistent height (rooftop is
all one constant height)
2. Multi-layer buildings : Buildings with inconsistent height (multi-layer rooftop)
12. Drawing rules
1. Buildings with consistent height (single layer)
• If only rooftop visible:
• Draw the rooftop contour in terms of the basic rules of
building construction (ie. perpendicular corners,
parallel sides, etc.)
• If building side-wall is also visible:
• First draw rooftop contour in terms of the basic rules
• Then, shift the rooftop contour to the base of the
building to capture the 3D structure: along the visible
side-wall direction, drag rooftop polygon to the
bottom (only necessary if the width of the visible side-
wall is greater than 3 pixels)
Please watch the training material video for more details
13. Drawing rules
1. Buildings with consistent height (single layer)
• If only rooftop visible: draw rooftop contour only
Simple shape complicated shape
Draw the rooftop only
14. 1. Buildings with consistent height
(single layer)
• If building side-wall is visible (no
less than 3 pixels), draw 3D
structure:
• First, draw the rooftop only.
• Then, shift the rooftop to
the bottom of the building:
along visible side-wall
direction, drag rooftop
outline to the bottom (see
yellow auxiliary lines
created)
Tips: A real 3D building structure is
generated.
Drawing rules
Draw the rooftop, then shift
Please watch the building training video
for more details
15. 2. Building with inconsistent height (multi-layer)
• We need to draw multi-layer structures for building with inconsistent
height. Please read “building interpretation guide” to figure out which
type of building need to draw multi-layer structures.
• Two ways to draw multilayer buildings:
• 1. Father & son method (lower layers contain upper layers)
• 2. Brother method (draw building components one by one)
Please watch the multi-layer building training video for more details.
We have some very helpful tools which let you draw perfect result.
Drawing rules
16. 2. Building with inconsistent height (multi-layer)
• 1. Father & son method (lower layers contain upper layers)
• First, draw the top-level rooftop, then along the visible side-wall
direction drag the rooftop polygon to the second highest rooftop
level;
• Second, draw the second level rooftop in a new polygon, then
along the visible side-wall direction drag the second level
rooftop polygon to the third highest rooftop level;
• Based on this “top to bottom” sequence, the rest rooftops can
be drawn in the same manner.
• This method only used when you see the top layers are right in
the middle of the building
Please watch the multi-layer building training video for more details.
We have some very helpful tools which let you draw perfect result.
Drawing rules
17. 2. Building with inconsistent height (multi-layer)
• Use “father & son” method.
Sample 1. Top layer in the middle of building.
Multi-layer
Drawing rules
18. 2. Building with inconsistent height (multi-layer)
• 2. Brother method (draw building components one by one)
• Find the brother component with the most obvious sidewall. Draw
this brother, then drag sidewall to bottom area.
• Then draw the nearest adjacent brother (component).
• Then draw other brothers (components) one by one.
• Tips: Software has very useful tools(trace tool H) to help you draw the
multilayer perfectly without any error
• Most of the multilayer buildings need to use this method to draw.
Please watch the multi-layer building training video for more details.
We have some very helpful tools which let you draw perfect result.
Drawing rules
19. 2. Building with inconsistent height (multi-layer)
• Use “brother” method. Draw building components one by one.
Sample 1. Single multilayer building. There are three components of
this building.
Correct
result
Drawing rules
3 components/brothers
20. 2. Building with inconsistent height (multi-layer)
• Use “brother” method. Draw building components one by one.
Sample 2. Multilayer layer building with cavity. Draw the 2
components one by one then exclude the ground area.
Multi-layer
Drawing rules
21. 2. Building with inconsistent height (multi-layer)
• Use “brother” method. Draw building components one by one.
Sample 3. Group of multilayer layer buildings. Should be no gap
between each other.
Multi-layer
Drawing rules
22. 2. Building with inconsistent height (multi-layer)
• Use “brother” method. Draw building components one by one.
Sample 4. Group of multilayer layer buildings (ring shape).
Multi-layer
Drawing rules
Please watch the multi-layer building training
video for more details. We have very helpful tools
which let you draw perfect result.
23. Important tips
1. For most multilayer buildings, you should use “brother method” to draw. It is
quicker and easier. We have very helpful tools which let you draw perfect result. If
you want draw quicker to earn more money, then use “brother method”!
2. For father & son method, only use it when the top layers are in the right middle of the
building.
