When working on architectural designs and Building Information Modeling (BIM) projects in Revit, it is crucial to effectively communicate the spatial relationships and dimensions of the building elements. While adding dimensions in a 2D floor plan or elevation view is common, adding dimensions in a 3D view can provide a more comprehensive understanding of the design. Here are the steps to add dimensions in a 3D view in Revit:

1. Open the 3D view: Start by opening the 3D view in Revit where you want to add dimensions. This can be a perspective view, axonometric view, or any other 3D representation of your design.

2. Use the 'Temporary Dimensions' tool: In the 3D view, select the 'Temporary Dimensions' tool from the ribbon. This tool allows you to add dimensions directly to the 3D elements without altering the model's actual dimensions.

3. Place dimensions on 3D elements: Click on the edge, face, or corner of the 3D element where you want to add a dimension. Revit will automatically display the temporary dimension measurement. Click to place the dimension in the desired location.

4. Adjust dimension styles: You can modify the appearance and style of the dimensions in the 3D view to suit your project requirements. Navigate to the 'Annotate' tab and access the 'Dimension Styles' to customize the dimension text, line style, and other properties.

5. Add temporary annotations: In addition to dimensions, you can also add temporary annotations such as spot elevations or detail lines in the 3D view to further enhance the communication of design intent.

By adding dimensions in a 3D view in Revit, you can create a more immersive and informative presentation of your architectural design. This not only aids in the visualization of the project but also helps in coordinating with other disciplines involved in the construction process. Make sure to leverage the 3D dimensioning tools in Revit to effectively convey the spatial relationships and measurements of your building elements in the 3D environment.