Lego Mosaics Using R

LEGO Mosaics in R

brickr

Overview

brickris a package for creating LEGO-esque 2D and 3D models using the R tidyverse and Tyler Morgan-Wall ’s rayshader package.

The package has two key uses:

• Converting image files in to 2D and 3D LEGO mosaics
• Building 3D LEGO models from simple data frames

Installation

# To install the latest version from Github:
# install.packages("devtools")
devtools::install_github("ryantimpe/brickr")

#For 3D features, rayshader is also required.
install.packages("rayshader")

3D Models

Currently, 3D models can be built from one of two data input formats: bricks_from_table() or bricks_from_coords() .

These functions are very experimental and will change. Better documentation will be released soon.

• bricks_from_table() converts a matrix-shaped table of integers into LEGO bricks. For simple models, this table can be made manually using data.frame() or tibble::tribble() . For more advanced models, it’s recommended you use MS Excel or a .csv file. The left-most column in the table is associated with the Level or z-axis of the model. The function by default converts this to numeric for you. Each other column is an x-coordinate and each row is a y-coordinate. More flexible inputs will be available in a future release.

• bricks_from_coords() takes a data frame with x , y , & z integer values, and Color columns, where each combination of x, y, & z is a point in 3-dimensional space. Color must be an official LEGO color name from display_colors() . This format is much more flexible than bricks_from_table() and allows the programatic development of 3D models.

Pass the output from any bricks_from_*() function to display_bricks() to see the 3D model.

library(brickr)

#This is a brick
brick <- data.frame(
  Level="A",
  X1 = rep(1,4),
  X2 = rep(1,4)
)

brick

##   Level X1 X2
## 1     A  1  1
## 2     A  1  1
## 3     A  1  1
## 4     A  1  1

brick %>% 
  bricks_from_table() %>% 
  display_bricks()

rayshader::render_snapshot()

Brick Colors

There are 2 ways to assign the color of the bricks. The display_colors() function helps with ID numbers and names

• Use the brickrID value instead of ‘1’ in the model input table. Values of ‘0’ are blank spaces.

• Create a table of color assignments and pass this to bricks_from_table()

brick_colors <- data.frame(
  .value = 1,
  Color = "Bright blue"
)

brick %>% 
  bricks_from_table(brick_colors) %>% 
  display_bricks()

rayshader::render_snapshot()

Stacking bricks

The Level column in the input table determines the height of the bricks. bricks_from_table() will convert alphanumeric levels into a z coordinate.

# A is the bottom Level, B is the top
brick <- data.frame(
  Level= c(rep("A",4), rep("B",4)),
  X1 = rep(1,4),
  X2 = rep(1,4)
)

brick %>% 
  bricks_from_table(brick_colors) %>% 
  display_bricks()

rayshader::render_snapshot()

The same process works with many levels

#You can stack many bricks ----
brick <- data.frame(
  Level="A",
  X1 = rep(1,4),
  X2 = rep(1,4)
)

#... And they can all be different colors ----
1:10 %>% 
  purrr::map_df(~dplyr::mutate(brick, Level = LETTERS[.x], X1 = .x, X2 = .x)) %>% 
  bricks_from_table() %>% 
  display_bricks()

rayshader::render_snapshot()

Full Models

For larger models, use tibble::tribble() to more easily visualize the model. For very large models, use MS Excel.

my_first_model <- tibble::tribble(
  ~Level, ~X1, ~X2, ~X3, ~x4, ~x5, ~X6, ~x7, ~x8,
  "A", 1, 1, 1, 0, 1, 1, 1, 1,
  "A", 1, 0, 0, 0, 0, 0, 0, 1,
  "A", 1, 0, 0, 0, 0, 0, 0, 1,
  "A", 1, 1, 1, 1, 1, 1, 1, 1,
  "B", 1, 0, 1, 0, 1, 1, 0, 1,
  "B", 1, 0, 0, 0, 0, 0, 0, 1,
  "B", 1, 0, 0, 0, 0, 0, 0, 1,
  "B", 1, 0, 1, 0, 0, 1, 0, 1,
  "C", 1, 1, 1, 1, 1, 1, 1, 1,
  "C", 1, 0, 0, 0, 0, 0, 0, 1,
  "C", 1, 0, 0, 0, 0, 0, 0, 1,
  "C", 1, 1, 1, 1, 1, 1, 1, 1,
  "D", 2, 2, 2, 2, 2, 2, 2, 2,
  "D", 1, 0, 0, 0, 0, 0, 0, 1,
  "D", 1, 0, 0, 0, 0, 0, 0, 1,
  "D", 2, 2, 2, 2, 2, 2, 2, 2,
  "E", 0, 0, 0, 0, 0, 0, 0, 0,
  "E", 2, 2, 2, 2, 2, 2, 2, 2,
  "E", 2, 2, 2, 2, 2, 2, 2, 2,
  "E", 0, 0, 0, 0, 0, 0, 0, 0
)

brick_colors <- tibble::tribble(
  ~`.value`, ~Color,
  1, "Bright blue",
  2, "Dark orange"
)
  
my_first_model %>% 
  bricks_from_table(brick_colors) %>% 
  display_bricks(theta = 210)

rayshader::render_snapshot()

Programmatically build models

Use bricks_from_coords() to programmatically build 3D LEGO models instead of manually drawing them in a spreadsheet or table. Here you must provide whole number coordinates for x, y, and z, along with an official LEGO color name for each point.

radius <- 4
sphere_coords <- expand.grid(
  x = 1:round((radius*2.5)),
  y = 1:round((radius*2.5)),
  z = 1:round((radius/(6/5)*3)) #A brick is 6/5 taller than it is wide/deep
) %>%
  mutate(
    #Distance of each coordinate from center
    dist = (((x-mean(x))^2 + (y-mean(y))^2 + (z-mean(z))^2)^(1/2)),
    Color = case_when(
      #Yellow stripes on the surface with a 2to4 thickness
      between(dist, (radius-1), radius) & (x+y+z) %% 6 %in% 0:1 ~ "Bright yellow",
      #Otherwise, sphere is blue
      dist <= radius ~ "Bright blue"
  ))

sphere_coords %>% 
  bricks_from_coords() %>% 
  display_bricks(phi = 30, theta = 30)

rayshader::render_snapshot()

Mosaics

The mosaic functions renders an imported JPG or PNG file using LEGO colors and bricks. The resulting mosaic can be viewed in 2D and 3D. A full explanation can be found on this blog post , this follow-up post ,and this third post .

mosaic1 <- jpeg::readJPEG("Images/goldengirls.jpg") %>% 
  image_to_bricks(img_size = 48) #Length of each side of mosaic in "bricks"

#Plot 2D mosaic
mosaic1 %>% display_set()

If you had previously created mosaics before the package release, the script below will still work.

mosaic1 <- jpeg::readJPEG("Images/goldengirls.jpg") %>% 
  scale_image(img_size = 48) %>% #Length of each side of mosaic in "bricks"
  legoize() %>%  
  collect_bricks()

2D Mosaics

image_to_bricks() can take a few important arguments:

• img_size Providing a single value, such as 48 , crops the image to a square. Inputting a 2-element array, c(56, 48) , will output a rectangular image of c(width, height) .

• color_table Data frame of possible brick colors in the mosaic. Defaults to the included data set lego_colors .

• brightness adjusts the light of the image. Values greater than 1 will lighten the image, while value less than 1 will darken it.

display_set() creates a ggplot of the image.

3D Mosaics

Two additional functions can convert the image_to_bricks() output into a 3D mosaic using the rayshader package by Tyler Morgan-Wall .

• collect_3d() translates the 2D LEGO mosaic into two matrices - one for the color image and one for the elevation of each point on the image. By default, the produced image has the height of 6 LEGO plates (2 LEGO bricks) with lighter colors having a higher elevation. Use mosaic_height to change the height of the mosaic and set highest_el = 'dark' to set the darker colors as the tallest bricks.

• display_3d() simply calls rayshader::plot_3d() , but pulls both the hillshade and elevation matrices from the output of collect_3d() and fixes some of the arguments. See ?rayshader::plot_3d() for more information.

library(rayshader)

mosaic1 %>% 
  collect_3d() %>% 
  display_3d(fov=0,theta=-20,phi=30,windowsize=c(1000,800),zoom=0.7)

render_snapshot()

LEGO Mosaics IRL

Additional functions assist in the translation from the LEGO mosaic image into a real LEGO set.

Instructions

Use generate_instructions() to break the LEGO mosaic image into easier-to-read steps for building the set. This defaults to 6 steps, but passing any integer value will generate that many steps.

mosaic1 %>% generate_instructions(9)

Piece list and count

Use display_pieces() to generate a graphic and count of all required plates or bricks (for stacked mosaics). These are sorted by color and size for easy purchase on LEGO.com’s Pick-a-Brick section using the advanced search option. Alternatively, use table_pieces() to produce a data frame table of all required bricks.

mosaic1 %>% display_pieces()