View angle control in MATLAB - Mini Project: Build & Apply

View angle control

📖 Scenario: You are working with 3D plots in MATLAB. Sometimes the default view angle makes it hard to see the shape clearly. You want to control the view angle to see the plot from different directions.

🎯 Goal: Create a simple 3D plot and change its view angle using MATLAB commands.

📋 What You'll Learn

Create a 3D plot using peaks data

Set a variable for the azimuth angle

Use the view function with the azimuth and elevation angles

Display the plot with the new view angle

💡 Why This Matters

🌍 Real World

Scientists and engineers often need to look at 3D data from different angles to understand shapes and patterns better.

💼 Career

Knowing how to control plot views is useful in data analysis, visualization, and presentations in many technical jobs.

1

DATA SETUP: Create 3D plot data

Create a variable called Z by calling peaks(30). Then create a 3D surface plot using surf(Z).

MATLAB

% Create variable Z with peaks data and plot it
% Your code here

Hint

The peaks function creates a nice 3D surface data. Use surf to plot it.

2

CONFIGURATION: Set azimuth angle variable

Create a variable called az and set it to 45 to represent the azimuth angle in degrees.

MATLAB

Z = peaks(30);
surf(Z);
% Create azimuth angle variable az and set it to 45
% Your code here

Hint

The azimuth angle controls the horizontal rotation of the view.

3

CORE LOGIC: Apply view angle control

Use the view function with the azimuth angle az and elevation angle 30 to change the plot view.

MATLAB

Z = peaks(30);
surf(Z);
az = 45;
% Set the view angle using azimuth az and elevation 30
% Your code here

Hint

The view function takes two arguments: azimuth and elevation angles in degrees.

4

OUTPUT: Display the plot with new view angle

Run the code to display the 3D plot with the view angle set by view(az, 30). The plot window should show the surface from the new angle.

MATLAB

Z = peaks(30);
surf(Z);
az = 45;
view(az, 30);
% Run to display the plot

Hint

Running this code will open a figure window showing the 3D surface from the specified angle.

Practice

1. What does the MATLAB command view(45, 30) do in a 3D plot?

easy

A. Changes the plot colors based on angles 45 and 30

B. Rotates the plot by 45 degrees around the z-axis only

C. Sets the viewpoint to 45 degrees azimuth and 30 degrees elevation

D. Zooms into the plot by a factor of 45 and tilts by 30 degrees

Solution

1. Step 1: Understand the view function parameters

   The view function takes two angles: azimuth (horizontal rotation) and elevation (vertical rotation).

2. Step 2: Interpret the given angles

   Here, azimuth is 45 degrees and elevation is 30 degrees, setting the viewpoint accordingly.

3. Final Answer:

   Sets the viewpoint to 45 degrees azimuth and 30 degrees elevation -> Option C

4. Quick Check:

   view(az, el) sets angles = D [OK]

Hint: Remember view(az, el) sets horizontal and vertical angles [OK]

Common Mistakes:

• Confusing azimuth with elevation
• Thinking view rotates plot instead of viewpoint
• Assuming view changes colors or zoom

2. Which of the following is the correct syntax to set the view angle to azimuth 90 and elevation 0 in MATLAB?

easy

A. view(90, 0);

B. view(90 0);

C. view(az=90, el=0);

D. view(azimuth=90, elevation=0);

Solution

1. Step 1: Recall MATLAB view function syntax

   The correct syntax is view(az, el) where az and el are numeric values.

2. Step 2: Check each option

   Only view(90, 0); matches the correct syntax. The others either omit the comma between arguments or use named parameters not supported by MATLAB's view function.

3. Final Answer:

   view(90, 0); -> Option A

4. Quick Check:

   Correct syntax is view(az, el) [OK]

Hint: Use view(az, el) with two comma-separated numbers, no named parameters [OK]

Common Mistakes:

• Omitting comma between arguments
• Trying to name parameters like az= or azimuth=
• Passing a vector instead of two separate arguments

3. What will be the effect of the following MATLAB code on a 3D plot?

surf(peaks);
view(0, 90);

medium

A. View from the front, showing the plot's height

B. View from directly above, looking down on the plot

C. View from the side, showing the plot's depth

D. View rotated 90 degrees around the x-axis

Solution

1. Step 1: Understand the view angles

   Azimuth 0 means looking along the x-axis, elevation 90 means looking straight down from above.

2. Step 2: Apply to the 3D plot

   Setting view(0, 90) shows the plot from directly above, flattening depth perception.

3. Final Answer:

   View from directly above, looking down on the plot -> Option B

4. Quick Check:

   view(0, 90) = top-down view [OK]

Hint: Elevation 90 means looking straight down [OK]

Common Mistakes:

• Thinking azimuth 0 means side view
• Confusing elevation 90 with front view
• Assuming rotation around x-axis changes view

4. Identify the error in this MATLAB code snippet for setting a 3D plot view:

plot3(x, y, z);
view(45 30);

medium

A. Missing comma between the two arguments in view

B. Missing semicolon after plot3 command

C. plot3 cannot be used with view function

D. Angles 45 and 30 are out of valid range

Solution

1. Step 1: Check the view function usage

   The view function requires two separate arguments separated by comma.

2. Step 2: Analyze the code snippet

   Using view(45 30) passes two numbers without comma separator, causing a syntax error.

3. Final Answer:

   Missing comma between the two arguments in view -> Option A

4. Quick Check:

   view needs two comma-separated numbers [OK]

Hint: Pass angles as two comma-separated numbers [OK]

Common Mistakes:

• Thinking semicolon omission causes error here
• Believing plot3 and view are incompatible
• Assuming angle values are invalid

5. You want to create a MATLAB script that shows a 3D surface plot of peaks and then rotates the view smoothly from azimuth 0 to 360 degrees at elevation 30 degrees. Which code snippet correctly achieves this?

hard

A. surf(peaks);
view(0, 30);
for az = 0:10:360
pause(0.1);
view(az, 30);
end

B. for az = 0:10:360
surf(peaks);
view(az, 30);
pause(0.1);
end

C. for az = 0:10:360
view(az, 30);
surf(peaks);
pause(0.1);
end

D. surf(peaks);
for az = 0:10:360
view(az, 30);
pause(0.1);
end

Solution

1. Step 1: Plot surface once before loop

   Plotting surf(peaks) once before the loop avoids redrawing the plot repeatedly, improving performance.

2. Step 2: Update view inside loop with pause

   Loop changes azimuth from 0 to 360, updating view angle smoothly with pause(0.1) to see animation.

3. Final Answer:

   surf(peaks); for az = 0:10:360 view(az, 30); pause(0.1); end -> Option D

4. Quick Check:

   Plot once, then loop view update = A [OK]

Hint: Plot once, then loop view changes with pause [OK]

Common Mistakes:

• Plotting inside the loop causing flicker
• Calling view before surf plot exists
• Not pausing to see the rotation effect