Building a TARDIS in BRL-CAD

This guide demonstrates how to build a TARDIS using BRL-CAD, an open-source CAD software. The instructions explain how to create the base, walls, windows, doors, roof, and light fixture, with detailed explanations for each BRL-CAD command used.

Outline of the Project

Install and Set Up BRL-CAD
Define the Basic Dimensions and Parameters
Create the Base and Walls of the TARDIS
Add Windows and Doors
Add Roof and Light Fixture
Apply Detailing and Color

1. Install and Set Up BRL-CAD

To begin, install BRL-CAD by following the instructions on their official website: https://brlcad.org. Open mged (BRL-CAD’s geometry editor) to begin entering commands directly.

2. Define the Basic Dimensions and Parameters

Define the dimensions of the TARDIS to ensure scalability and proper proportions. We will use the following variables:

set width 100               # Width of the TARDIS base in mm
set height 200              # Total height of the TARDIS
set wall_thickness 5        # Wall thickness
set roof_height 30          # Height of the roof section
set door_height 130         # Door height
set window_height 30        # Window height

3. Create the Base and Walls of the TARDIS

We use the in command to create geometric shapes. In this case, we use arb8 and rpp primitives.


# Create a hollow box for the TARDIS body
in base.r arb8 -$width/2 -$width/2 0 $width/2 -$width/2 0 $width/2 $width/2 0 -$width/2 $width/2 0 -$width/2 -$width/2 $height $width/2 -$width/2 $height $width/2 $width/2 $height -$width/2 $width/2 $height
in hollow_base.r rpp -$width/2 -$width/2 0 $width/2 $width/2 $height
comb walls.c - base.r - hollow_base.r

Explanation of Commands

in: The command to create a new geometry object. Each object is given a name, followed by its type and parameters.
arb8: An 8-point Arbitrary Convex Polyhedron, ideal for creating a box with 8 vertices.
rpp: Right Parallelepiped, defined by two opposite corners, which is often used for rectangular prisms.
comb: Creates a combination (or group) of objects. Here, walls.c is a combination that subtracts hollow_base.r from base.r to create hollow walls.

4. Add Windows and Doors

We will add rectangular cutouts on each side for the windows and a larger cutout for the door on the front face. Each of these cutouts will also use the in command with the rpp primitive.

Windows


# Define the window dimensions and position
in window.r rpp -$window_width/2 -$window_width/2 $window_height $(window_height + 10) $wall_thickness $width
comb windows.c - window.r - base.r

Explanation of Commands

window.r: This is the name of the new object, which represents a window cutout.
rpp: Creates a rectangular shape for each window by defining the two opposite corners of the rectangular prism.
comb: windows.c subtracts window.r from base.r to create a window space.

Doors


# Define the door dimensions and position on the front face
in door.r rpp -$width/4 -$width/4 0 $width/4 $door_height $wall_thickness
comb door.c - door.r - windows.c

Explanation of Commands

door.r: This object represents a door cutout.
rpp: Defines the rectangular door shape by specifying two opposite corners.
comb: door.c subtracts door.r from windows.c to form a door space.

5. Add Roof and Light Fixture

The roof is a pyramid shape created with the arb4 primitive. A sphere will serve as the light fixture on top of the roof.


# Create the pyramid-shaped roof
in roof.r arb4 -$width/2 -$width/2 $height $width/2 -$width/2 $height $width/2 $width/2 $height -$width/2 $width/2 $height $roof_height

# Add a light fixture on the top center of the roof
in light.r sphere 0 0 $height+$roof_height 5
comb roof_light.c u roof.r u light.r

Explanation of Commands

arb4: A four-point arbitrary convex polyhedron, ideal for creating the triangular roof shape by specifying four vertices.
sphere: Creates a spherical object; here, it’s used to create the light fixture at the roof’s peak.
u: Union operator. In roof_light.c, it unites roof.r and light.r into a single combination.

6. Apply Detailing and Color

BRL-CAD allows adding color to materials with the mater command.


# Adding color
mater base.r "plastic" "blue" 128 128 255
mater light.r "glass" "light" 255 255 255

Explanation of Commands

mater: Defines material properties and color for objects. Here, plastic and blue are used for the base, while glass and light are used for the light fixture.
128 128 255: RGB values representing the color blue.