To change the height of an eave in Revit, the primary method involves adjusting the "Offset From Roof Base" or "Plate Offset From Base" parameter for the slope-defining boundary lines while the roof is in sketch mode.
Understanding Eave Height Control in Revit
An eave is the part of a roof that projects beyond the face of a wall. In Revit, the vertical position of an eave is determined by the roof's overall base height (its reference level and offset) and the slope defined by its boundary lines in the roof's footprint sketch. To individually modify an eave's height, you essentially change the relative height of its corresponding sketch line.
Key Concepts:
- Roof Sketch Mode: This is the environment where you define the roof's shape using magenta boundary lines.
- Slope-Defining Boundary Lines: These are the lines in the roof sketch that have the "Defines Slope" checkbox enabled in the Properties palette. They are crucial as they dictate the roof's pitch and, consequently, the eave's height at that edge.
- Offset Parameters: These values are applied to individual sketch lines to raise or lower that specific edge relative to the main roof base.
Step-by-Step Guide to Adjusting Eave Height
There are two main approaches to modify eave heights in Revit: adjusting individual boundary line offsets for precise control over specific eaves, or uniformly moving the entire roof's base.
Method 1: Adjusting Boundary Line Offsets (Recommended for Individual Eave Control)
This method allows for fine-tuning the height of specific eave edges, creating varied rooflines or accommodating specific design requirements.
- Select the Roof: In a floor plan view or a 3D view, select the roof element you wish to modify.
- Enter Sketch Mode: On the Modify | Roofs tab, locate and click the "Edit Footprint" button (for footprint-based roofs) or "Edit Profile" (for extrusion roofs). This action will switch the view to the roof's sketch mode, displaying the magenta boundary lines.
- Select a Slope-Defining Boundary Line: While in sketch mode, select one of the boundary lines that define the roof's slope. These lines typically show a slope arrow or have the "Defines Slope" property checked in the Properties palette.
- Adjust the Offset Parameter: With the slope-defining boundary line selected, navigate to the Properties palette. Here, you will find parameters related to the line's elevation.
- Locate either "Offset From Roof Base" or "Plate Offset From Base".
- Specify a positive or negative numerical value for the chosen offset parameter.
- "Offset From Roof Base": This is the most commonly used parameter. A positive value (e.g.,
1'-0") will lift the bottom edge of the roof (where it meets the wall plate) at that specific boundary line above the roof's overall base level. This effectively raises the eave height. Conversely, a negative value will lower it. - "Plate Offset From Base": This parameter appears when the "Rafter Cut" property for the roof type is set to "Plumb Cut" (or similar options) and specifically relates to the top of the wall plate. It serves a similar function to "Offset From Roof Base" but is specific to certain rafter cut configurations.
- "Offset From Roof Base": This is the most commonly used parameter. A positive value (e.g.,
- Repeat as Necessary: If multiple eave edges require different heights, select each relevant slope-defining boundary line and apply the desired offset value.
- Finish Edit Mode: Once all your adjustments are complete, click the green checkmark (Finish Edit Mode) on the contextual ribbon to apply the changes and exit the roof sketch mode.
- Practical Insight: Using "Offset From Roof Base" on a slope-defining line allows you to create varied eave heights around the perimeter of a single roof, which is essential for complex roof designs or matching existing conditions.
Method 2: Adjusting the Overall Roof's Base (For Uniform Eave Changes)
This method affects the entire roof structure, including all its eaves, by uniformly moving it up or down.
- Select the Roof: In any appropriate view (plan, section, 3D), select the roof element.
- Modify Base Parameters: In the Properties palette, under the "Constraints" section, adjust the following:
- Base Level: Change the reference level to a different floor or level in your project.
- Base Offset From Level: Enter a positive or negative numerical value. A positive value will move the entire roof and all its associated eaves upward from the selected Base Level, while a negative value will move them downward.
This method is ideal for global adjustments when the entire roof needs to be repositioned, rather than just individual eave edges.
Key Parameters for Eave Height Control
Understanding the specific parameters is crucial for effective roof modeling in Revit.
| Parameter | Description | When to Use |
|---|---|---|
| Offset From Roof Base | Adjusts the relative height of a specific slope-defining boundary line from the roof's overall base. | To achieve different eave heights on various sides of a roof, or to create stepped/split roof plates at the perimeter. This directly affects the vertical position of the eave at that line. |
| Plate Offset From Base | Similar to "Offset From Roof Base," but specific to the top of the wall plate for "Plumb Cut" rafter types. | When your roof type's rafter cut property is set to "Plumb Cut" (or similar), this parameter offers a precise way to control the plate height, which in turn defines the eave height for those specific roof constructions. |
| Base Offset From Level | Shifts the entire roof element (and all its eaves) up or down uniformly from its assigned Base Level. | For global height adjustments of the entire roof. If you need to raise or lower the whole roof structure, this is the most efficient method, as it maintains the relative eave heights and slopes. |
| Base Level | Sets the reference level (e.g., Floor 2, Roof Level) from which the roof's height is primarily calculated. | To anchor the roof to a specific storey or construction level within your building model. Changing this will move the entire roof (and its eaves) to align with the new reference level's elevation. |
For further detailed information and visual examples, you can refer to official Autodesk Revit documentation on creating and modifying roofs.
