Place Voids is a Revit Assistant extension that helps you automatically place opening voids in a host model based on linked models. It is designed for engineers and architects who need to coordinate penetrations for ducts, pipes, cables, or other elements passing through walls, slabs, and similar building elements.
The extension reads provisions for openings from linked models, places matching void families in the active Revit model, and optionally combines multiple layers into a single opening where appropriate.
The configuration is presented in the Assistant UI when you add the Place Voids task to a workflow. Each setting maps directly to a property in the configuration (PlaceVoidsArgs).
When the extension runs, it performs the following main steps:
- Checks that there is an active Revit document. If not, it stops and reports that no active document is available.
- Collects and prepares the void families that will be used for the openings (round and rectangular opening families). If these families are not already present in the project, the extension will automatically download and load them into the model.
- Starts a Revit transaction group called "Place Voids Command" so that all changes are grouped as one operation.
- Prompts you to select provisions for openings from linked Revit models. You pick the linked elements (for example, openings or reserved spaces) that should become voids in the host model.
- Reads information about previously created voids stored in the model so that it can track and coordinate with existing openings.
- Builds a request that includes:
- The active document
- The linked elements you selected
- The available void families (round and rectangular)
- The host elements to cut (from the
Elements to cut setting)
- Existing stored data about previously created voids
- The
Combine Different Layers setting
- Calls the internal void creation service, which calculates where and how to place void families, which hosts to cut, and how to handle combined layers based on your configuration.
- Commits the transaction group. If anything fails during this process, the transaction is rolled back and you get an error message.
- Shows a final message summarizing how many provisions were processed, how many failed, and details for each failure or processed opening.
If no elements are successfully processed, or if any elements fail, a failure message is returned so that you know the run did not complete as expected.
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Prepare your models
- Open the host Revit model where you want the voids to be placed.
- Link in the model(s) that contain provisions for openings (for example, MEP or coordination models) and ensure they are up to date.
- Make sure you are working in an appropriate view for selecting linked elements (3D view is recommended).
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Configure the task in Assistant
- Add the
Place Voids extension as a task in your Assistant workflow.
- In the configuration panel:
- Set Elements to cut to include the walls, slabs, or other host elements that should be cut by the voids. Ensure it uses the active document only.
- Choose whether to enable Combine Different Layers depending on whether you want combined openings across multiple layers.
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Run the extension
- Start the workflow that contains the
Place Voids task.
- When prompted in Revit, select the linked elements that represent provisions for openings. These are usually elements in a linked MEP or coordination model.
- Confirm your selection. The extension will then calculate and place the void families in the host model.
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Verify the results
- Inspect the host model in 3D and relevant plan/section views.
- Check that voids are placed at the correct locations and that the expected host elements are being cut.
- If you enabled Combine Different Layers, verify that multi-layer situations are represented by a single clean opening where appropriate.
- Causes: The extension was started when no Revit project was open, or a dialog took focus without an active document.
- Solution: Open the Revit project where you want to place voids, make sure it is the active document, and run the workflow again.
- Resources: Revit help on managing projects and views.
- Causes:
- The selected linked elements do not contain valid provision data.
- The Elements to cut filter does not include the host elements actually intersecting the provisions.
- The required void families could not be loaded.
- Solution:
- Verify that you selected the correct linked elements (provisions for openings, not other geometry).
- Check and adjust the Elements to cut configuration so it includes the relevant walls, slabs, or structural members.
- Ensure you have an internet connection so families can be downloaded if missing. If your network blocks the download, ask your IT or tools administrator.
- Resources: Internal coordination guidelines for provisions for openings and host element categories.
- Causes: Network restrictions, missing access to the Azure DevOps repository, or file permission issues in the temporary folder.
- Solution:
- Confirm you have network access to your organization's Azure DevOps.
- Try running Revit with appropriate permissions.
- If problems persist, request that the families
CW Opening Round.rfa and CW Opening Rectangular.rfa be provided and loaded manually into the project.
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Q: When should I use the Place Voids extension?
- A: Use Place Voids when you receive models with provisions for openings (for example, from MEP engineers) and need to place coordinated openings (voids) in your architectural or structural Revit model.
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Q: Does the extension support multiple Revit documents at once?
- A: No. The configuration for Elements to cut is set to use only the active document and does not support multiple documents in one run.
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Q: What if I already have voids in the model?
- A: The extension reads stored data about previously created voids and uses that information to coordinate with new provisions. However, you should still visually inspect existing openings to ensure they match current requirements.
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Q: Are there any view requirements?
- A: You must be in a view that allows you to select the linked elements representing provisions for openings. A 3D view is usually the most reliable.