Building and Storey Structure in ARCHLine.XP

Overview

One of the fundamental organizational units of an ARCHLine.XP BIM model is the Building.

A project can contain one or more buildings. Each building has its own independent storey structure, which defines the vertical organization of the building.

The storey management system in ARCHLine.XP follows the physical structure of real buildings: a building consists of storeys arranged one above another, and each storey has a defined starting elevation and vertical extent.

Therefore, storeys are not independent elevation reference planes but interconnected parts of a continuous building structure.

This approach makes the modeling of multi-storey buildings simpler and more consistent and helps prevent elevation inconsistencies between storeys.

1. A Project Can Contain Multiple Buildings

ARCHLine.XP supports managing multiple independent buildings within a single project.

This is particularly useful when designing residential complexes, institutional facilities consisting of several buildings, industrial facilities, or building wings with different heights.

Each building can have:

• its own number of storeys and storey names,
• independent storey heights,
• different starting elevations,
• its own floor plan structure.

For example, a project may contain Building A with four storeys and Building B with two storeys. The storeys of the two buildings do not necessarily have to be located at the same elevations.

Users can switch between buildings and storeys using the Project Navigator.

2. Building Storeys Are Physically Connected

ARCHLine.XP uses a vertically connected storey structure within each building.

Each storey has two fundamental elevation parameters:

Bottom Elevation

The elevation of the lower reference plane of the storey within the project coordinate system.

Storey Height

The vertical extent of the storey, which determines the starting elevation of the next storey.

The bottom elevation of the next storey is calculated as the sum of the bottom elevation and height of the previous storey.

E(n+1) = E(n) + H(n)

Where:

• E(n) is the bottom elevation of the current storey,
• H(n) is the height of the current storey,
• E(n+1) is the bottom elevation of the next storey.

Example: A Three-Storey Building

In this example, the First Floor begins exactly at the upper boundary of the Ground Floor.

If the Ground Floor height is changed from 3.20 m to 3.50 m, the bottom elevations of the storeys above it change accordingly.

This ensures the continuity of the building's storey structure.

3. Internal Level Offset – Mezzanine / Split Level

In real buildings, floor levels may occur that do not coincide with the main building storeys.

Typical examples include:

• split-level residential buildings,
• mezzanine floors,
• intermediate landings,
• rooms with different floor elevations.

ARCHLine.XP handles these situations using the Split Level Height feature.

A split level height defines an additional elevation reference within an existing building storey, allowing architectural elements to be placed at a different height.

Importantly, a split level height does not create a new, independent building storey.

Elements placed using a split level height still belong to the original building storey; they are simply positioned at a different elevation.

Example

Consider a Ground Floor with a bottom elevation of ±0.00 m and a storey height of 3.60 m.

We want to create a mezzanine at an elevation of +1.50 m within the Ground Floor.

To achieve this, we can define a split level height of 1.50 m.

The mezzanine slab and its associated elements can then be placed at an elevation of +1.50 m while remaining part of the Ground Floor.

The next independent building storey still begins at +3.60 m.

Therefore, a split level height does not modify the main storey structure of the building.

For more information, see Special structures such as half-stories, mezzanines.

4. Storey-Related Architectural Elements

The storey management system in ARCHLine.XP not only determines the vertical arrangement of storeys but also controls the elevation relationships of architectural elements.

The elevation parameters of walls, slabs, and other architectural elements can be linked to reference elevations associated with the building storeys.

These references may include:

• Finish Floor (FF),
• Top of Structure (TS),
• Bottom of Structure (BS),
• False Ceiling (CE).

By using the appropriate elevation relationships, elements linked to these references can automatically adapt when the storey height is modified.

This reduces the need for manual adjustments and improves the consistency of the BIM model.

For more information, see Storey (level bounded) parameters.

5. Differences Between ARCHLine.XP and Revit Storey Management

Different BIM applications may use different approaches to organizing the vertical structure of a building.

One important conceptual difference between ARCHLine.XP and Autodesk Revit lies in how building storeys and elevation references are defined.

In ARCHLine.XP, building storeys form a continuous, physically connected structure, with each storey positioned directly above the previous one.

Revit, on the other hand, uses freely positioned elevation reference levels, called Levels. These levels do not necessarily represent independent architectural storeys.

For example, a Revit Level may define an intermediate structural elevation or another important elevation reference plane.

Comparison

The difference between these two systems does not mean that one approach is universally better than the other. They represent different modeling concepts.

The ARCHLine.XP approach is particularly well suited to design tasks where the goal is to model the actual storeys of a building directly and clearly.

Revit's more flexible level management provides greater freedom in defining independent elevation reference planes.

6. When Should You Create a New Storey and When Should You Use a Split Level Height?

A new building storey should be created when you need to model a new, independent floor of the building with its own floor plan editing environment.

A split level height should be used when certain elements need to be placed at a different elevation within an existing building storey, without creating a new independent floor.

For example, a three-storey residential building can be modeled using three main storeys, even if the Ground Floor contains an intermediate mezzanine.

However, if a section of the building has its own distinct storey structure, it may be appropriate to manage that section as a separate building within the same project.

Summary

The ARCHLine.XP BIM model is organized around buildings, each consisting of independent but vertically connected storeys.

This storey structure follows the physical organization of a real building and ensures consistent elevation relationships between storeys.

The Split Level Height feature allows intermediate floor elevations to be managed without creating additional building storeys.

This approach supports both straightforward modeling of multi-storey buildings and the creation of more complex building structures with different internal elevations.