iat 106 spatial thinking and communicating fall 2012 lab 3--developing visual 3d skills: how to...

IAT 106Spatial Thinking and CommunicatingFall 2012

Lab 3--Developing visual 3D skills:

How to solve missing view problems and other mysteries of 3D worlds

<Lab3-F2012-HowTo-missviewMissline-v3.pptx>

http://students.surrey.sfu.ca/techone

M4(I).2IAT 106: Multiview

Objectives for the lab

• Learn how to

• Do simple isometric drawings1

• Do simple multiview drawings

And overall -- develop visualizing skills so that you can

• move back & forth among isometric ( & other pictorial) & multiview drawings to develop your ideas

1 Lecture 4 will provide additional detail about

isometric drawings, as part of “pictorial” projections.


Developing Visualizing Skills 1/7

• Important to develop skills for– Looking at multiview and visualizing the object (or drawing a

pictorial such as an isometric)– Looking at the object and being able to sketch a multiview

• Text: shows several ways to develop these skills:– Projection studies: look at examples of combined multiview &

iso (Recommended: study text fig 5-104, make sure you see the correspondence between iso and each ortho view)

– Build sample physical models

Try these


Adjacent Areas: Developing Visualizing Skills 2/7

Adjacent areas: (key concept) surfaces which are next to each other.

• Visible line: intersection between 2 planes; so …

• Boundary between surfaces shows as a line indicating a change in planes

• No 2 adjacent areas can lie in same plane (i.e. if there is a line, the 2 adjacent planes must not be co-planar)

Try to apply this notion: given a top view, sketch several possible objects

• You Try It: sketch a possible 3-view OR isometric that has the top view shown:


Adjacent Areas: Developing Visualizing Skills 3/7

The problem: do 3-view or iso that matches the given top view:

Possible solutions:

What was yours?



One Technique:

Surface Labeling: – You did this in Lab. – Analysis by Solids and by

Surfaces are similar

Vertex Labeling:

• Can help as check in multiview drawing


Similar Shapes: Developing Visualizing Skills 5/7

Similar shapes:

• apply rules 5 & 6: a surface will keep its basic configuration in all views (except of course on edge); so …– e.g. If it looks like an ‘ell’ in one view, it’ll look like an ell in ALL views

“Ell” “U” Inverted “T”


Convention: Arrangement of Orthographic Views

Height

Depth

Width

Front View

Top View

Right Side View

Remember the glass box: projecting the object onto its faces and unfolding the faces results in the view placement shown:

… and this is the STANDARD view arrangement; you must follow this in all multiview drawings

NB: distance between Top/Front & Front/Side is arbitrary; you can adjust it. It corresponds to the size of the Glass Box compared to the overall object size.BUT Top/Front MUST be aligned! Same for F/Side



Another technique: Missing Line exercises

What’s missing from this multiview?



How to: Missing View exercises


Projection Between Views

• Given two views of any point, the same point in any other orthographic view can be found

• A 45º mitre line is used to locate points and transfer depth dimensions between top and side views

Why does this work?

See slide 17: • reflecting thru 45 deg line is equiv

to rotation of 90 deg!

• So reflection is like swinging camera 90 deg or

• Rotating R side of glass box 90 deg


Align Bounding Boxes of each View

WIDTH

WIDTH

HE

IGH

T

HE

IGH

TD

EP

TH

DEPTH

FRONT

TOP

RIGHT

Miter line at 45°


Sketch Features – View Projection

FRONT

TOP

RIGHT

Miter line at 45°


1. Visible

2. Hidden3. Center

Line “Order”

Draw lines in this order:


Add missing view in indicated location.(is there a missing line?)


Add missing view in indicated location.(is there a missing line?)

… don’t forget the missing line!


Add missing view in indicated location.


In doing this lab, you’ll have learned --

• How to do an orthographic projection:– Plan views, front views and side views

• Combining P, F and S into multiview drawings

• How to do an isometric drawing

• How to use all of this in solving visualization problems like missing view and missing line

• Start to develop skills to think and work in 3D, to be able to move back and forth among these views in order to develop your ideas, and to understand those of others


• That’s all!

iat 106 spatial thinking and communicating fall 2012 lab 3--developing visual 3d skills: how to...

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