# Creating A Child Model From Parent Model In collaborative bridge design, splitting a project into a **parent model** and one or more **child models** lets engineers work on different parts of the structure independently while keeping control over when and how changes are merged. The **parent model** (or **master model**) is the authoritative source — it reflects the final design decisions. Engineers create child models from the parent to work on specific components (superstructure, substructure, foundation, etc.) without immediately affecting the rest of the project. This is particularly useful when several engineers or teams collaborate. For example, one engineer can iterate on superstructure options in one child model while another focuses on foundation details in another. When iterations are complete, changes can be synced back into the parent model in a controlled way. Conversely, all child models can be refreshed from the latest parent at any time. This parent-child structure in OpenBrIM provides: * Clear separation of responsibilities across teams or disciplines. * Flexible iteration without prematurely overwriting shared data. * Centralized control over the final integration. The result is a scalable, organized workflow that scales well to large or complex bridge projects. ## Prepare the Master Project 1. **Add users.** Open the master project. Each engineer who will work on a child model must be added here — otherwise they cannot see the master and cannot create a child model from it. Assign permissions: * **Read-Only** — view only, no changes. * **Write** — edit shared data. * **Admin** — full control, including managing users and settings. See the screenshots for the menu locations. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-195837.png?api=v2) ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-195909.png?api=v2) ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-195919.png?api=v2) ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-201345.png?api=v2) 2. **Configure shared objects.** In the master project, navigate to the **Shared Objects** section. This defines which objects are shared with the child projects. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194204.png?api=v2) 3. In a typical master/child workflow you'll want to share **all** project objects so child models have everything they need. Click **Set to All Project Objects**. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194227.png?api=v2) ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194241.png?api=v2) ## Create a Child Model 1. Now create a child model so engineers can work on individual components. For example, one engineer can create a child model dedicated to **substructure piers** while another refines **plate girder dimensions** in a separate child model. To keep this guide simple, the example uses the **All-in-One Bridge** workflow. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194326.png?api=v2) 2. If you are not using the All-in-One Bridge workflow, import the **External References** workflow with the **Import New Workflow** button. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194827.png?api=v2) ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194841.png?api=v2) 3. Open the model, click the **Settings** icon to switch workflow, then choose **External References**. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194410.png?api=v2) 4. You can pull data from multiple models into a single working model. For example, store all project alignments in one model and all bridge data for a single continuous unit in another. Adding multiple rows under **External References** links these sources together so the consolidated data is available in the working model. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194423.png?api=v2) 5. Click the three-dot menu and choose **Add Projects**. The dialog lists all your available projects. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194440.png?api=v2) 6. Type the project name in the search box to filter. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194459.png?api=v2) ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194517.png?api=v2) 7. Click **Sync Project** to import all shared objects from the master model. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194542.png?api=v2) 8. Click **Zoom Extents** to view the full model. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194605.png?api=v2) ## Mark Local Objects to Protect Your Changes 1. Switch back to your active workflow and identify which objects you are working on so they aren't overwritten on the next sync. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194621.png?api=v2) 2. In the tree view, the objects synced from the parent appear with **sync** active. Each future sync will overwrite the local data for those objects with whatever the master model contains. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194632.png?api=v2) 3. For example, if you are working on plate girders and want to protect your changes, click **Disable Sync**. Future syncs will leave those objects untouched. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194658.png?api=v2) 4. Disabled-sync objects show a distinct purple color with an unlock icon in each row. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194715.png?api=v2) 5. When another engineer (e.g. the substructure designer) updates the master model and notifies you, return to **Sync** to pull their changes into your model and see whether they affect your results. ![](https://openbrim.atlassian.net/wiki/download/attachments/3238133773/image-20250808-194735.png?api=v2) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.openbrim.org/quick-guides/creating-a-child-model-from-parent-model.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. 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