> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ideatura.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# External Wall Dimensions

> Build an automation that follows the external façade perimeter and places three dimension strings around the building.

Build an automation that follows the external façade perimeter and places dimensions around the building. Define what each string measures, how far it sits from the façade and which plans to process.

## 1. Start with your own plan

Open a floor plan in Revit and save your work. Start with one representative plan containing external walls, openings and building grids.

Think through the building’s outline. A rectangular building, a stepped façade and several separate wings need different treatment. The automation should identify the perimeter and work along each façade side, placing dimensions outside the building.

This starting plan includes **1** straight façades and **2** angled corners. The red dimensions inside the plan come from the separate internal-wall example.

![Starting Revit plan with a straight façade marked 1 and an angled corner marked 2.](https://mintcdn.com/ideatura/5D9AI98lSNtfmB6z/images/external-wall-dimensions/perimeter.svg?fit=max\&auto=format\&n=5D9AI98lSNtfmB6z\&q=85\&s=d2928409bade91cfb7f3b118db20de70)

## 2. Describe the automation you want

Open a new chat in Ideatura and explain the drawing you want to produce. For example:

> Create an automation for external wall dimensions in selected floor plans. Follow the building’s façade perimeter and place three dimension strings outside each side, parallel to that façade.
>
> The closest string should capture wall ends, door and window openings, and curtain grids. The second should locate the host-model building grids between the façade endpoints. The third should show the overall length of that façade side.
>
> Add controls for the plans, excluded wall types, dimension style and three offsets in millimetres. Include options to move dimension numbers and display the detected perimeter for checking. Show me the controls before running.

The generated card below includes **1 Run with parameters**.

**Following the perimeter is the key instruction.** Explain how dimensions should turn with the façade, respond to recesses and remain associated with the correct building or wing.

![Generated exterior-wall automation with Run with parameters marked 1.](https://mintcdn.com/ideatura/5D9AI98lSNtfmB6z/images/external-wall-dimensions/automation.svg?fit=max\&auto=format\&n=5D9AI98lSNtfmB6z\&q=85\&s=9d709a37192e14ce0bd60a317180e617)

## 3. Define the three strings

Separate detailed setting-out information from grid positions and overall dimensions.

| String | What it measures | Example offset |
| - | - | - |
| First — closest | Wall ends, door and window openings, and curtain grids | 1,500 mm |
| Second — middle | Façade endpoints and host-model building grids within that span | 2,000 mm |
| Third — outermost | Overall length of the façade side | 2,500 mm |

These offsets are starting values. Adjust them to suit the drawing scale, surrounding annotations and available space.

At corners, check that the dimensions reference the intended façade ends. At openings, confirm that the references correspond to the edges you want to measure.

![Actual façade detail: opening and curtain-grid string, building-grid string and overall length.](https://mintcdn.com/ideatura/5D9AI98lSNtfmB6z/images/external-wall-dimensions/strings.svg?fit=max\&auto=format\&n=5D9AI98lSNtfmB6z\&q=85\&s=fee6c61f453d56a79b011942d8540fb0)

## 4. Build the controls

Ask Ideatura to expose the choices you will need when reusing the automation.

| Control | How to use it |
| - | - |
| **Floor plans** | Select one floor plan for the first test, then extend to other plans. |
| **Excluded wall types** | Exclude wall types that should not contribute to the perimeter or its dimensions. |
| **Linear dimension style** | Choose the project’s required linear dimension style. |
| **Closest, Middle and Outermost offset (mm)** | Set each string’s distance from the façade in millimetres. |
| **Move dimension numbers** | Enable text adjustment where dimension values need more space. |
| **Draw perimeter lines** | Display the detected perimeter and placement guides to help inspect the result. |

The form below shows **1** plans, **2** style, **3** the three offsets and **4 Run**. Optional perimeter lines help inspect the outline during testing.

![Exterior dimension controls with plans, style, offsets and Run numbered.](https://mintcdn.com/ideatura/5D9AI98lSNtfmB6z/images/external-wall-dimensions/controls.svg?fit=max\&auto=format\&n=5D9AI98lSNtfmB6z\&q=85\&s=9496c197b4291407f681a0a2798ec47b)

## 5. Test the perimeter and refine the result

Run the automation on one plan. Read the report, then inspect the dimensions in Revit. This example created 27 exterior strings and skipped duplicates on a repeat run.

**Check the view’s cut plane.** Here, the low entrance storefront sits below it, so the entrance recess remains undimensioned. Resolve the relevant model or view condition before asking the automation to complete that area.

Check that the perimeter follows the intended façade, the strings sit outside it and each string measures the correct references. Inspect corners, recesses, openings and curtain-wall bays closely.

For stepped façades, angled walls, separate buildings or courtyards, describe the required treatment explicitly and test a representative area. Curved façades need their own dimensioning rules.

Give a focused correction when something is wrong:

> At the recessed entrance, follow the two returns and the recessed façade. Keep each dimension string outside its corresponding face. Leave the dimensions on the other façades unchanged.

Before rerunning, decide how to handle dimensions already created so the test does not leave duplicates. Once satisfied, save the automation with a clear name and description, then test it on another plan before using it more widely.

![Revit plan after the exterior dimension run, including angled corners.](https://mintcdn.com/ideatura/5D9AI98lSNtfmB6z/images/external-wall-dimensions/result.svg?fit=max\&auto=format\&n=5D9AI98lSNtfmB6z\&q=85\&s=99cdf90138f32ad8666ffbf1e9a429b1)


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