Modular Building [UE Plugin]

1. Design architecture parametrically using Rhino3D and Grasshopper

tip

You may use any 3D modeling software, such as Blender, as long as the final exported model includes an .fbx 3D model file and a corresponding data file containing the bounding box vertex data for each geometric object (see below). This will allow for automatic assembly in UE.

Download Parametric Design Models and Code (Rhino3D + Grasshopper)

Download Rhino3D Custom Plugin RH4UE (used for exporting model data)

Download the exported .fbx files and .csv datasets

Download the parametric design (Grasshopper) plugin Moths from food4rhino

A-Node-based programming (Graph) in Grasshopper

The graph code can be obtained directly from the downloaded file. If you are using another 3D modeling software for your design, you may ignore this part and refer directly to the exported .fbx model and the corresponding .csv data file format.

B-Use the developed RH4UE plugin (Rhino3D) to assist in exporting the data file of the 3D model

tip

Obtain the RH4UE plugin from the downloaded file mentioned above.

This is the plugin of the developed RH For UE Toolset, which includes two main functions: object renaming and CSV export of positioning data.

Renaming Function:

The program iterates through the objects currently selected by the user in Rhino and automatically assigns each a unique new name based on its layer. The naming rules can be configured to either "start numbering from 0" or "continue from the maximum number already used on that layer." By parsing existing names using regular expressions and maintaining a set of used numbers and the current maximum, the program ensures no duplicates are generated. This enables standardized and conflict-free batch naming within each layer.

CSV Export Function:

The program reads the selected objects’ attribute names (or uses their IDs as a fallback), calculates their axis-aligned bounding boxes (AABB) in the world coordinate system, and retrieves the coordinates of all eight corner points. It then writes each object’s data to the CSV file line by line, including the identifier and the 3D coordinates of each vertex. Standard CSV escaping rules are applied, ensuring compatibility with downstream data analysis or external spatial positioning workflows.

The exported .fbx 3D model and the corresponding .csv format data. You can export the .fbx model and the corresponding .csv geometric data either by unit or based on any set of geometric objects intended for assembly.

RowName	MeshName	Corner0_X	Corner0_Y	Corner0_Z	Corner1_X	Corner1_Y	Corner1_Z	Corner2_X	Corner2_Y	Corner2_Z	Corner3_X	Corner3_Y	Corner3_Z	Corner4_X	Corner4_Y	Corner4_Z	Corner5_X	Corner5_Y	Corner5_Z	Corner6_X	Corner6_Y	Corner6_Z	Corner7_X	Corner7_Y	Corner7_Z
apparatus_0	apparatus_0	95.988	2358.8	1115.54	1216.34	2358.8	1115.54	1216.34	2533.79	1115.54	95.988	2533.79	1115.54	95.988	2358.8	1908.01	1216.34	2358.8	1908.01	1216.34	2533.79	1908.01	95.988	2533.79	1908.01
stairs_glasses_4	stairs_glasses_4	312.729	3274.07	0	312.729	3274.07	0	312.729	4310.98	0	312.729	4310.98	0	312.729	3274.07	590	312.729	3274.07	590	312.729	4310.98	590	312.729	4310.98	590
stairs_glasses_7	stairs_glasses_7	162.729	3274.07	0	162.729	3274.07	0	162.729	4310.98	0	162.729	4310.98	0	162.729	3274.07	590	162.729	3274.07	590	162.729	4310.98	590	162.729	4310.98	590
stairs_railings_18	stairs_railings_18	307.729	4310.98	590	317.729	4310.98	590	317.729	4328.99	590	307.729	4328.99	590	307.729	4310.98	608.687	317.729	4310.98	608.687	317.729	4328.99	608.687	307.729	4328.99	608.687
stairs_railings_21	stairs_railings_21	307.729	3274.07	90	317.729	3274.07	90	317.729	4315.48	90	307.729	4315.48	90	307.729	3274.07	602.172	317.729	3274.07	602.172	317.729	4315.48	602.172	307.729	4315.48	602.172

2. Import and assemble the building using the Modular Building plugin in Unreal Engine – User Manual

After installing the ModularBuilding plugin, a "EUW Modular Building Toolset" button will appear under the Tools menu. Click it to launch the plugin.

The Modular Building Plugin provides a suite of productivity tools inside Unreal Engine Editor Utility Widgets (EUWs) to speed up the handling of modular assets, from folder management to building assembly.

This manual explains the workflow and details each of the seven functional modules, helping designers and technical artists streamline asset preparation, data integration, and automated assembly.

Modular Building - V1.1

Modular Building - V1.2

---

1. Generate Folder

Purpose: Quickly create standardized folder structures in your project’s Content Browser for organizing modular building assets.

How to Use:

• Launch the EUW for the plugin.
• Click Generate Folder.
• A dialog will appear (powered by open_directory_dialog.py) for you to choose a base path.
• The system will auto-generate subfolders (e.g., Meshes, Materials, Blueprints, DataTables) for consistent asset organization.

Benefit: Ensures all team members follow a unified directory structure, reducing confusion and manual setup time.

---

2. One-click Add Collision

Purpose: Automatically generate convex collision meshes for selected Static Mesh assets.

How to Use:

• In the Content Browser, select one or multiple Static Mesh assets.
• Click One-click Add Collision in the EUW.
• The script (generate_kinetic_convex_collision.py) runs EditorStaticMeshLibrary.generate_kinetic_convex_collision.
• The selected meshes are updated with convex collision and marked dirty for saving.

Benefit: Eliminates repetitive manual collision setup and ensures assets are game-ready with one click.

---

3. Assign Material by Prefix

Purpose: Assign materials to static meshes based on naming prefixes or DataTable whitelist.

How to Use:

• Select a root folder, a set of Static Meshes, or a DataTable containing mesh names.

• Provide:

  • Prefix Filter (e.g., Blocks, Windows*)
  • Material Asset Path

• Run Assign Material by Prefix.

• The script (assign_material_by_prefix.py) matches meshes against the prefix or DataTable and assigns the chosen material.

Benefit: Ensures consistent material assignment for large asset sets, following naming conventions or structured data.

---

4. Harvest and Reparent

Purpose: Extract and reorganize components from existing Blueprints while preserving hierarchy and reparenting relationships.

How to Use:

• Select Blueprint assets in the Content Browser or Blueprint actors in the Level.

• Click Harvest and Reparent.

• The system (harvest_blueprint.py) will:

  • Safely duplicate components without name collisions.
  • Copy transform, materials, and key properties.
  • Reattach components to maintain hierarchy.
  • Save a new “_harvest” Blueprint to the specified folder.

Benefit: Creates clean, reusable modular Blueprints from existing assets or actors, preserving structure and avoiding duplicated names.

---

5. Group & (Optional) Axis

Purpose: Group meshes by distance or other rules and optionally create virtual axis helpers for alignment.

How to Use:

• In the Level Editor, select actors or meshes.
• Activate Group & Axis.
• The system groups meshes and creates SceneComponent-based axes (when enabled) as parents.

Benefit: Simplifies modular hierarchy setup (e.g., doors → door handles), keeps pivots aligned, and allows optional axis parenting for animation or control.

---

6. Import CSV → DataTable

Purpose: Convert CSV files into Unreal DataTables based on a row struct definition.

How to Use:

• Prepare a CSV file (columns must match FBuildingMeshData from BuildingMeshData.h, e.g., MeshName, Corner0_X, …).

• In the EUW, choose Import CSV → DataTable.

• Provide:

  • CSV path
  • Destination folder (must start with /Game/...)
  • Row Struct (usually FBuildingMeshData)

• Script (import_csv_to_datatable.py) will create or overwrite a DataTable.

Benefit: Bridges external design data (e.g., Rhino/Grasshopper exported CSVs) into Unreal Engine for direct use in modular assembly workflows.

---

7. Assemble Building

Purpose: Automatically assemble building blocks into a complete modular building inside Unreal Engine using data-driven workflows.

How to Use:

• Prepare a DataTable (from step 6) with mesh names and placement data.
• In EUW, select Assemble Building.
• The system spawns actors or Blueprints according to DataTable entries and groups them under a master building actor.

Benefit: Reduces manual drag-and-drop work, enables repeatable parametric-like building assembly directly in Unreal Engine.

---

8. Merge Components → StaticMesh

Purpose: Convert selected Blueprint components or placed actors into standalone Static Mesh assets for optimization, reuse, archiving, or Nanite conversion in Unreal Engine.

How to Use:

• Select one or more Blueprints (in Content Browser) and/or Actors (in the Level).
• Open the Modular Building EUW and choose Merge Components → StaticMesh.
• Specify a target folder (e.g., /Game/MergedAssets/BuildingParts/).
• (Optional) Enable Nanite.
• Click Run Merge — system auto-spawns temp preview actors (for BP), collects visible StaticMeshComponents, merges them, builds & saves StaticMesh, and syncs to Content Browser.

Benefit: Transforms modular Blueprint assemblies or placed building elements into single StaticMesh assets. Greatly improves performance, ease of reuse, LOD/Nanite workflows, and supports asset export pipelines for large projects or procedural generation results.

---

The Modular Building Plugin integrates asset management, collision setup, material assignment, Blueprint harvesting, grouping, data import, and automated assembly into a single workflow.

By leveraging these seven tools, teams can drastically reduce manual repetitive tasks, ensure consistency across assets, and enable data-driven design-to-engine pipelines.

This plugin is particularly suited for workflows involving parametric modeling, digital construction, and AR/VR simulation, making Unreal Engine a hub for both design iteration and final deployment.

---

info

Using the Modular Building plugin, a complex architectural structure consisting of 25 units was imported and assembled.