Alembic

GISBox is a one-stop 3D GIS data editing, conversion and publishing platform that supports editing in multiple GIS formats such as OSGB/GEOTIFF/RVT, converting to 3DTiles/Terrain and publishing.

Introduction

Alembic is an open source geometry cache file format and related software tools widely used in the field of computer graphics. It is mainly used to efficiently transmit and exchange complex geometric data, especially animation and simulation data, between different 3D software and renderers. It is also gradually emerging in the field of geographic information systems (GIS). It can accurately store the vertex positions, animation keyframes, deformation information, etc. of 3D models, and has good compression performance, which can effectively reduce the amount of data and improve data transmission and storage efficiency.

Data Format Overview

Geometry Data

Meshes: Support polygonal meshes, subdivision surfaces, triangle/quad patches. Store vertex positions, normals, UV coordinates, vertex colors and other properties
Curves: Support NURBS curves, Bezier curves, splines, etc.
Particles: Support point cloud data, record the position, speed, life cycle and other properties of each particle
Volumes: Support voxelized data (such as smoke and fluid simulation results).

Animation Data

Vertex Animation: Record the position changes of vertices in each frame (such as character facial expressions, cloth simulation).
Deformations: Support skinning, blend shapes, lattice deformations, etc.
Transformations: Record the displacement, rotation, scaling and other transformation information of the object (support parent-child hierarchical relationship).

Hierarchy and Scene Structure

Supports parent-child hierarchical relationships of objects (such as the hierarchical structure of character skeletons).
Stores object visibility, hidden status, instantiation information, etc.

Custom Properties

Supports user-defined metadata (such as material ID, grouping tags, simulation parameters, etc.).

Pros

Efficient and lightweight: only cache information is recorded, not stored frame by frame, which greatly reduces the file size and is suitable for complex scenes.
Cross-software compatibility: open source features support data exchange between different 3D software and improve collaboration efficiency.
Performance optimization: improve project loading speed and fluency, especially suitable for real-time rendering needs.

Cons

Functional limitations: animation details (such as textures and materials) are not supported and must be used in combination with other formats (such as FBX).
Modification limitations: external Alembic files cannot be modified after being referenced by the project, otherwise it may cause a crash.

Application Scenario

Alembic has a wide range of application scenarios in GIS software. In the field of urban planning, it can be used to integrate urban building models from different modeling software, and integrate building details, textures, and animation effects into the city’s 3D geographic information model, so that planners can more intuitively evaluate the rationality of building layouts and design plans, and conduct simulations such as sunlight analysis and sight analysis.

Example

Open the file in Alembic.

Export Alembic file.