Day 12: 30-days to learn rgl, plotly, and gganimate - Create a Time-Based 3D Animation Using rgl and gganimate

 

Step 1: Install Required Packages

Before starting, ensure the following packages are installed:

install.packages(c("rgl", "ggplot2", "gganimate", "ggimage"))

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Step 2: Generate 3D Frames Using rgl

1.     Setup the Environment: Create a 3D scatter plot that rotates over time.

library(rgl)

# Create a 3D scatter plot

n <- 100  # Number of points

x <- rnorm(n)

y <- rnorm(n)

z <- rnorm(n)

col <- rainbow(n)

open3d()  # Initialize the 3D plot

plot3d(x, y, z, col = col, size = 5)

2.     Rotate and Save Frames: Capture frames by rotating the plot over time and saving each frame as an image.

frames_dir <- "frames"

dir.create(frames_dir, showWarnings = FALSE)  # Create a directory for frames

# Generate and save frames

for (i in 1:100) {

    view3d(userMatrix = rotationMatrix(pi * i / 50, 0, 1, 0))  # Rotate around Y-axis

    snapshot3d(file.path(frames_dir, paste0("frame_", sprintf("%03d", i), ".png")))

}

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Step 3: Animate Frames Using gganimate

1.     Prepare Frame Data: Load the saved frames and prepare a data frame for animation.

library(ggplot2)

library(gganimate)

library(ggimage)

# List saved frames

frame_paths <- list.files(frames_dir, full.names = TRUE)

# Create a data frame

frame_df <- data.frame(

    frame = frame_paths,

    time = 1:length(frame_paths),  # Time points for animation

    x = 0,  # Placeholder for x-coordinate

    y = 0   # Placeholder for y-coordinate

)

2.     Build the Animation: Use gganimate to create the animation from the frames.

animation <- ggplot(frame_df, aes(x = x, y = y, image = frame)) +

    geom_image(size = 1) +              # Add images to the plot

    transition_time(time) +            # Transition over the time variable

    enter_fade() +                     # Fade-in effect

    exit_fade() +                      # Fade-out effect

    theme_void()                       # Remove unnecessary plot elements

3.     Save the Animation: Export the animation as a GIF.

anim_save("3d_time_animation.gif", animation)

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Step 4: Review and Debug

• Check the saved animation in your working directory (3d_time_animation.gif).
• If the animation doesn’t look smooth, adjust the number of frames or transition settings.

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Key Notes

1. Custom Rotation: You can modify the view3d() function to rotate around different axes or add zoom effects.
2. Image Quality: Ensure the rgl frames are saved with high resolution for better animation quality.
3. Animation Effects: Experiment with different gganimate effects like ease_aes() or transitions (transition_states()).