Console tool for exporting Instanced 3D Models (i3dm's or glb's with EXT_mesh_gpu_instancing), i3dm composites (cmpt), subtree files and tileset.json from PostGIS table.
The input table contains instance information like location (epsg:4326), binary glTF model (glb), scale, yaw/pitch/roll (or legacy rotation) and instance attributes.
The 3D tiles created by this tool are tested in Cesium JS.
Sample of trees in Cesium viewer using instanced 3D Tiles in Lyon:
For instanced 3D Model (i3dm) specs see https://github.com/CesiumGS/3d-tiles/tree/master/specification/TileFormats/Instanced3DModel
For composite tile (cmpt) specs see https://github.com/CesiumGS/3d-tiles/blob/master/specification/TileFormats/Composite/README.md
Options:
1] Use pre-built binaries from release
2] Use .NET Tool
Prerequisite: .NET 8.0 SDK is installed https://dotnet.microsoft.com/download/dotnet/8.0
$ dotnet tool install -g i3dm.export
Or update
$ dotnet tool update -g i3dm.export
3] Use Docker
$ docker run geodan/i3dm.export
Trees sample with implicit tiling:
https://geodan.github.io/i3dm.export/samples/traffic_lights/cesium/
Input database table contains following columns:
. geom - geometry with Point or PointZ for instance positions;
. scale - double with instance scale (all directions);
. yaw - double with yaw/heading in degrees (clockwise-positive); . pitch - double with pitch in degrees; . roll - double with roll in degrees;
Non-GPU (i3dm) mode supports yaw/pitch/roll. For backwards compatibility, if yaw/pitch/roll columns are missing the tool will fall back to legacy rotation (deprecated) and print a warning (rotation is treated as yaw; pitch/roll = 0).
. tags - json with instance attribute information;
. model - byte[] or string column with glb or name of binary glTF model per instance. Should be valid path on tool runtime or valid uri on display in client;
. (optional) scale_non_uniform - double precision[3] - for scale per instance in 3 directions.
See testdata/create_testdata.sql for script creating sample table.
Tool parameters:
-c: (required) connection string to PostGIS database
-t: (required) table with instance positions
-g: (optional - Default: 1000) Geometric error
-o: (optional - Default: ./tiles) Output directory, will be created if not exists
-q: (optional - Default: "") Query to add to the where clauses (for example: -q "id<5460019"). Be sure to check indexes when using this option.
--use_scale_non_uniform: (optional - default false) Use column scale_non_uniform for scaling instances
--max_features_per_tile (optional - default 1000). Maximum number of features/instances of tile
--geometrycolumn: (optional - default: geom) Geometry column name
--use_gpu_instancing (optional - default false) Use GPU instancing (only for Cesium)
--boundingvolume_heights (option - default: 0,10) - Tile boundingVolume heights (min, max) in meters. The heights will be added to the z_min and z_max values of the input geometries.
--tileset_version (optional - default "") - Tileset version
--use_i3dm (optional - default false) Use I3dm format - only first model will be processed (false creates Cmpt - Only when creating I3dm's)
--use_external_model: (optional - default false) Use external model instead of embedded model (Only when creating I3dm's)
--use_clustering: (optional - default false) If tile contains more than max_features_per_tile instances, its number of instances will be reduced to max_features_per_tile by clustering
--keep_projection: (optional - default false) Keep the original projection of the input table.
The input table can defined in
1] Global coordinates
WGS84 longitude, latitude in degrees + height in meters with ellipsoid as reference (EPSG:4979)
2] Local coordinates (for release 2.12.0 and higher)
Any projected coordinate system height in meters with geoid as reference
For example in the Netherlands use composite EPSG:7415 (Amersfoort / RD New (EPSG:28992) + NAP height in meters (EPSG:5709)).
On runtime the tool will reproject the instance positions to EPSG:4978 (ECEF coordinates) for creating the 3D tiles.
When option keep_projection is set to true, the original projection of the input table is preserved and used for creating the 3D tiles. Note that when using this option, the client application must support the original projection of the input table for correctly displaying the Instanced 3D Tiles, like 3DTilesRenderer/Giro3D/ITowns/QGIS Web Client (QWC).
See https://hub.docker.com/r/geodan/i3dm.export
To run in Docker mount drives:
-
/app/output: mount for the result tileset.json, subtree files and content files;
-
/glb: mount when using file based input glb's - remember to add the /glb path to the model in the database. For example '/glb/my_model.glb'.
Example:
$ docker run -it -v $(pwd)/output:/app/output -v $(pwd)/glb:/glb geodan/i3dm.export -c "database_connection_string" -t table
$ i3dm.export -c "Host=localhost;Username=postgres;Password=postgres;Database=test;Port=5432" -t public.trees
For getting started with i3dm.export tool see getting started.
For a detailed explanation of how instance transforms are computed (ECEF/ENU to glTF Y-up, handedness, matrix conventions, and GPU instancing TRS composition), see:
1] Benchmark on Daily Digital Obstacles files
Source: https://www.faa.gov/air_traffic/flight_info/aeronav/digital_products/dailydof/
588094 instances worldwide, Content tiles generated: 2345, Subtree files generated: 372
Time generating I3dm --use_gpu_instancing false: 0h 0m 43s 799ms
Time generating GLB --use_gpu_instancing true: 0h 0m 47s 879ms
By default, the instance model is embedded directly in the i3dm payload. In the i3dm header, the value gltfFormat is set to 1. In this case, the model must be provided as a valid file path to a binary glTF (.glb) file. Only the i3dm files need to be copied to the production server.
When the parameter use_external_model is set to true, the i3dm payload contains only the model name instead of the embedded binary glTF. In the i3dm header, the value gltfFormat is set to 0. In this case, the model must be specified as a valid absolute or relative URL pointing to a binary glTF (.glb) file. The client application is responsible for downloading the binary glTF files. Both the i3dm files and the referenced binary glTF files must be copied to the production server.
The use_external_model option is only available when --use_gpu_instancing is set to false.
Starting with release 2.0, every tile is generated as a composite tile (.cmpt), even if the tile contains only one model.
According to the OGC 3D Tiles specification (https://docs.opengeospatial.org/cs/18-053r2/18-053r2.html#249 ), a composite tile (cmpt) can contain multiple tile formats. In this implementation, each composite tile contains a collection of instanced 3D model tiles (i3dm).
For each unique model in a tile, one i3dm file is created. The resulting .cmpt file bundles all i3dm tiles for that tile. Even if there is only a single model, it is still wrapped inside a .cmpt file.
Multiple models are supported. You can specify different models in the model column (for example, a deciduous tree model and a conifer tree model). For each unique model, a separate i3dm tile is generated. If multiple models are present in the same tile, the composite tile (.cmpt) will contain multiple i3dm files, one for each unique model.
If the option --use_i3dm=true is set, only i3dm tiles are created and no composite (.cmpt) tile is generated. When multiple models are present in a tile and --use_i3dm=true is used, only the first model is processed.
Starting release 2.0, tiles are generated according to the 3D Tiles 1.1 Implicit Tiling technique. Tiles are generated in a quadtree, maximum number of features/instances is defined by parameter 'implicit_tiling_max_features'.
Content tiles will be generated in output folder 'content', subtree files will be created in folder 'subtrees'. In the root output folder file 'tileset.json' will be created.
To add batch info to instanced tiles fill the 'tags' type json column in the input table.
For example:
[{"customer" : "John Doe"}, {"id" : 5454577}]
Note:
. all instance records per tile should have the same properties (in the above case 'customer' and 'id'). The list of properties is determined from the first instance in the tile;
. only key - value is supported, not more complex structures.
Sample to update the json column in PostgreSQL:
postgres=# update i3dm.my_table set tags = json_build_array(json_build_object('customer','John Doe'), json_build_object('id',id));
The batch table information in the i3dm tile is stored as follows (for 2 instances):
{"customer":["John Doe","John Doe2"], "id": [5454577, 5454579]}
The root bounding volume in Tileset.json is calculated from the input table in 3 dimensions (xmin, ymin, xmax, ymax, zmin, zmax).
-
The values for the boundingbox (xmin, ymin, xmax, ymax) are increased by 10%;
-
The height values (zmin, zmax) are increased by the value of setting 'boundingvolume_heights' (default 0,10).
Note: Positions outside xmin, ymin, xmax, ymax -180, -90, 180, 90 in wgs84 are not supported.
When the instance model should be scaled in three directions (x, y, z) use the --use_scale_non_uniform option (default false)
When using this option, the column 'scale_non_uniform' will be used for scaling instances.
Column 'scale_non_uniform' must be of type 'double precision[3]'.
Sample queries to create/fill this column:
Create column:
postgres=# ALTER TABLE traffic_signs_instances
postgres=# ADD COLUMN scale_non_uniform double precision[3]
Fill column:
postgres=# update traffic_signs_instances set scale_non_uniform = '{10.0, 20.0, 30.0}'
When using large tables create a spatial index on the geometry column:
psql> CREATE INDEX ON m_table USING gist(geom)
In 3D Tiles 1.1, GPU instancing is supported. This means that the same model can be used for multiple instances within a glTF (using EXT_mesh_gpu_instancing - https://github.com/KhronosGroup/glTF/blob/main/extensions/2.0/Vendor/EXT_mesh_gpu_instancing/README.md). Files like I3dm/cmpt are no longer created.
Attribute information can be added to the instances using glTF 2.0 extensions
-
EXT_instance_features - https://github.com/CesiumGS/glTF/tree/3d-tiles-next/extensions/2.0/Vendor/EXT_instance_features
-
EXT_structural_metadata - https://github.com/CesiumGS/glTF/tree/3d-tiles-next/extensions/2.0/Vendor/EXT_structural_metadata
There is an experimental option to create 3D Tiles 1.1 using GPU instancing: --use_gpu_instancing (default false).
This option is currently in development.
Live demo trees in Grenoble with GPU instancing and metadata:
https://bertt.github.io/cesium_3dtiles_samples/samples/1.1/grenoble_trees/
The following features should work:
-
Attribute information from tags;
-
Positioning, Rotation (roll, pitch, yaw) and Scaling of instances.
To use this option, the input table should contain columns 'roll', 'pitch' and 'yaw'.
Sql script to add the columns (and migrate legacy rotation if present):
alter table instances add column if not exists yaw double precision default 0;
alter table instances add column if not exists pitch double precision default 0;
alter table instances add column if not exists roll double precision default 0;
-- rotation was historically used as heading/yaw
update instances set yaw = rotation where rotation is not null;
-- optional cleanup (breaking):
-- alter table instances drop column if exists rotation;
When the input model (GLB/GLTF) references external image textures (for example *.png), exported tiles keep those textures external in both modes:
- GPU instancing (
--use_gpu_instancing=true) - non-GPU instancing (
--use_gpu_instancing=false) when using embedded model payloads (--use_external_model=false)
On export, textures are written once to:
output/content/textures/<modelName>/<textureFile>
and each generated tile payload references them via a relative URI:
textures/<modelName>/<textureFile>
This significantly reduces dataset size when many tiles share the same model + textures.
If the input model has embedded images, they remain embedded in each exported tile.
-
When using GPU instancing, for the attributes the 'string' type is used (so no support for other types yet);
-
No support for multiple meshes/nodes in the input model;
-
composite tiles (formerly known as cmpt). Support is added for multiple models in a tile (like multiple models in a composite cmpt file). There is a known issue with showing the attribute information in Cesium. See CesiumGS/cesium#11683
Warning: When the input glTF model has transformations, the model will be transformed twice: once in the glTF and once for the instance translations. In some cases it's better to remove the transformations from the input model. For example tool 'gltf-tansform' - function clearNodeTransform (https://gltf-transform.dev/modules/functions/functions/clearNodeTransform) can be used to clear local transformations.
- Getting attributes in Cesium does not work when there are multiple input models https://community.cesium.com/t/upgrade-3d-tileset-with-composite-cmpt-tile-to-1-1-attribute-data-missing/33177/2
There is an experimental option to create 3D Tiles using clustering: --use_clustering (default false).
When this option is off, dense tiles with number of instances exceeding max_features_per_tile aren't rendered. With this option such tiles are rendered with number of instances that is exactly equal to max_features_per_tile. Number of instances is reduced in the following way:
- tile instances are clustered with MiniBatchKMeans algorithm with number of clusters equal to
max_features_per_tile; - from each cluster single instance is picked randomly.
number of instances: 2500
max_features_per_tile: 100
tileset generation time:
- without clustering : 0h 0m 0s 539ms
- with clustering: 0h 0m 1s 238ms
Run from source code:
$ git clone https://github.com/Geodan/i3dm.export.git
$ cd i3dm.export/src
$ dotnet run -- -c "Host=myserver;Username=postgres;Password=postgres;Database=test;Port=5432" -t public.trees
To develop in Visual Studio Code, open .vscode/launch.json and adjust the 'args' parameter to your environment
"args": ["-c" ,"Host=myserver;Username=postgres;Database=test;Port=5432", "-t", "my_table"],
Press F5 to start debugging.
2026-02-19: release 2.16.0: add support for yaw, roll, pitch rotations in no GPU instancing mode (legacy rotation is deprecated but will be treated as yaw)
2026-02-17: release 2.15.0: improve gpu instancing picking for multi node model and fix for pitch, roll, yaw rotations
2026-02-13: release 2.14.1: fix for keep_projection option
2026-02-13: release 2.14.0: add support for keep_projection and add support for external textures when using GPU instancing
2026-02-05: release 2.13.0: fix clustering status messages
2024-10-30: release 2.12.0: add support for cartesian projected input coordinates
2024-12-20: release 2.11.0: add clustering + change ellipsoid
2024-10-31: release 2.10.0: add multiple mesh support in input model + gpu instancing tags null checking + vertical precision
2024-10-15: release 2.9.0: add tileset version option
2024-08-01: release 2.8.3: fix release
2024-08-01: release 2.8.2: fix for I3dm using rtc_center for high precision positions
2024-07-22: release 2.8.1: fix release
2024-07-22: release 2.8.0: to .NET 8.0
2024-06-20: release 2.7.4: fix for composite tiles when using GPU instancing
2024-06-13: release 2.7.3: add support for other input source EPSG codes than 4326
2024-06-10: release 2.7.2: fix gpu instancing yaw, pitch, roll, remove mapbox code (parameter -f --format)
2024-06-08: release 2.7.1: fix for disappearing instances
2023-03-28: release 2.7.0: add support for EXT_structural_metadata
2023-11-08: release 2.6.0: Add support for GPU instancing (experimental), removed option -r RTC_CENTER
2023-10-18: release 2.5.0: Improved root bounding volume calculation, improved batch table handling
2023-09-27: release 2.4.5: Get boundingvolume z from input table + option boundingvolume_heights removed
2023-09-27: release 2.4.4 change default -r (relative positions) from false to true
2023-06-20: release 2.4.3 fix for generating 1 tile
2023-02-21: release 2.4.1 fix version number
2023-02-21: release 2.4 split root subtree file in multiple subtree files
2023-01-30: release 2.3.2 improve spatial index performance
2022-10-05: release 2.3.1 bug fix for showing all instances per tile
2022-10-05: release 2.3 add support for byte[] type column (in addition to string) for glb's from database
2022-08-31: release 2.2 renamed parameter 'implicit_tiling_max_features' to 'max_features_per_tile', fix skewed bounding volumes
2022-08-09: release 2.1 use 1 geometric error as input parameter
2022-08-08: release 2.0 adding 3D Tiles 1.1 Implicit Tiling.
Breaking change:
Parameters removed: -e and -s (extent tile and super extent tile)
Parameters added: implicit_tiling_max_features (default 1000)
2021-10-04: release 1.9 adding Cesium support
2020-11-12: release 1.8 add external tileset support
2020-11-12: release 1.72. to .NET 5.0
2020-11-05: release 1.7.1 with bug fix wrong instances per i3dm when multiple models used.
2020-11-05: release 1.7 add support for composite tiles (cmpt). Breaking change: parameter -m --model is removed. Model can now be defined per instance in the input table.
2020-10-28: release 1.6 add scale_non_uniform support
2020-10-21: release 1.5 add query, use_external_model parameters
2020-10-20: release 1.4 add batch info support
2020-10-20: release 1.3 adding instance rotation + rtc_Center support
2020-10-19: release 1.2 with instance scale support
2020-10-19: add support for uri references to external glTF's.
2020-10-15: Initial coding