dotbim (Version 1.0.0)

Introduction

Introducing an open-source, accessible and simple file format for BIM.

Created by BIM developers for BIM developers.

An idiot admires complexity, while a genius appreciates simplicity - Terry Davis

BIM vs IFC comparison

	.bim	.ifc
Is it open?	Yes	Yes
Is it free?	Yes	Yes
Type	Text file	Text file
What it contains	Geometry + data attached	Geometry + data attached in a standardized way
Types of geometries allowed	Triangulated meshes only	A lot of different types: meshes, extrusions, b-reps etc.
Pages of documentation	1	100+

To see much more extended comparison check out Dion's comparison here: paireks#8

Community

Let's get this community bigger. Share it with your friends and colleagues that want to see a new BIM format: https://discord.gg/uhvx9sysvW

NuGet package

https://www.nuget.org/packages/dotbim/

Structure

File size

File size depends on the level of the deduplication made by exporter. You can reference the same mesh multiple times, which can have huge impact on decreasing the size when there is a lot of duplicate meshes.

Files created are also much more efficient once the user's meshes are being optimized, e.g. removing duplicate vertices or better discretization of geometry highly reduce the file size as well.

Documentation

Main information

.bim
License: MIT
JSON structure
x, y, z coordinates should be in meters
Decimal point should be used
JSON objects and properties should start with lowercase and with underscore as a seperator between words, e.g. schema_version

file

File contains 4 properties:

schema_version is the version of schema used in this file as string. Current one is "1.0.0".

mesh

mesh_id is integer >= 0 to reference this mesh later in element.

coordinates

It is a big array of all coordinates of a mesh. It is structured in this way:

[X0, Y0, Z0, X1, Y1, Z1, X2, Y2, Z2, X3, Y3, Z3, ..., XN, YN, ZN]

Let's say our mesh is defined by 3 vertices: (0.0, 0.0, 0.0), (10.0, 0.0, 0.0) and (10.0, 5.0, 0.0), then your vertices_coordinates will look like this:

[0.0, 0.0, 0.0, 10.0, 0.0, 0.0, 10.0, 5.0, 0.0]

Later in faces_ids we refer to these vertices by their order.

indices

It is a big array of ids (integers) that define all faces in a mesh. It is structured in this way:

[Face1_Id1, Face1_Id2, Face1_Id3, Face2_Id1, Face2_Id2, Face3_Id3, Face3_Id1, Face3_Id2, Face3_Id3, ..., FaceN_Id1, FaceN_Id2, FaceN_Id3]

If we'd like to create one-face mesh using vertices_coordinates from an example above, then it will look like this:

[0, 1, 2]

Pyramid example:

  "coordinates": [
    0.0,
    0.0,
    0.0,
    10.0,
    0.0,
    0.0,
    10.0,
    10.0,
    0.0,
    0.0,
    10.0,
    0.0,
    5.0,
    5.0,
    4.0
  ],
  "indices": [
    0,
    1,
    2,
    0,
    2,
    3,
    0,
    1,
    4,
    1,
    2,
    4,
    2,
    3,
    4,
    3,
    0,
    4
  ]

element

guid is a string that can be used for comparison of different elements.

"guid": "76e051c1-1bd7-44fc-8e2e-db2b64055068"

vector

Vector places referenced mesh where it should be placed as an element. It should have 3 properties:

x (value)
y (value)
z (value)

  "vector": {
    "x": 9.9266016462536122,
    "y": 3.3910972817343494,
    "z": 52.239445879618685
  }

rotation

Rotation rotates referenced mesh how it should be rotated as element. It is a quaternion. It should have 4 properties:

qx (value) - first imaginary coefficient of the quaternion
qy (value) - second imaginary coefficient of the quaternion
qz (value) - third imaginary coefficient of the quaternion
qw (value) - real part of the quaternion

  "rotation": {
    "qx": 0.63979295771454925,
    "qy": 0.10626982147910254,
    "qz": -0.12472093047736807,
    "qw": -0.7508770776915008
  }

color

color should have 3 properties:

r (integer between 0-255) - red
g (integer between 0-255) - green
b (integer between 0-255) - blue
a (integer between 0-255) - alpha

  "color": {
    "r": 255,
    "g": 255,
    "b": 0,
    "a": 255
  }

type

Element type. It is a string that specifies what mesh represents. E.g. "Beam", "Plate".

"type": "Beam"

info

info is just a dictionary with string as key and value.

  "info": {
    "Name": "Teapot",
    "Price": "2.50$"
  }

Authors

Wojciech Radaczyński

Advisors

Tom Van Diggelen
Harry Collin
Marios Messios

ricardyn/dotbim