Allplan BIM Workflow: From 2D Drawings to 3D Building Models and IFC Export

Allplan BIM Workflow: From 2D Drawings to 3D Building Models and IFC Export

I started using Allplan on a project in Munich about four years ago, and what impressed me was how smoothly it handles the transition from 2D drafting to 3D BIM. You don't have to commit to full BIM from the start — you can begin with 2D plans and progressively build up the 3D model. That flexibility is rare in BIM software. Let me walk you through the workflow from 2D drawings to IFC export.

Project Setup

Creating a New Project

1. File > New > Project
2. Set project name and location
3. Configure coordinate system:
   • Local: For standalone projects
   • Global/Gauss-Krueger: For surveying integration
4. Set units: millimeters (metric) or feet/inches (imperial)
5. Set floor structure:
   • Define building stories (e.g., Basement, Ground Floor, Floor 1, Floor 2, Roof)
   • Set elevation for each story (e.g., Basement: -3.000m, Ground: 0.000m, Floor 1: +3.500m)

Layer and Pen Setup

Allplan uses a pen-based system combined with layers:

1. Format > Pen Settings
2. Configure standard pens:
   • Pen 1: 0.35mm (walls, structure)
   • Pen 3: 0.25mm (secondary elements)
   • Pen 5: 0.15mm (annotations, dimensions)
   • Pen 7: 0.10mm (hatching, details)
3. Format > Layer Settings
4. Create standard layers following a naming convention (e.g., A-WALL, A-DOOR, A-WIND)

2D Drawing Preparation

Importing Existing DWG/DXF

1. File > Import > DWG/DXF
2. Select the file
3. Set import options:
   • Layers: Map to Allplan layers
   • Pens: Map to Allplan pen numbers
   • Scale: Verify 1:1 import
4. Clean up imported geometry:
   • Use Modify > Clean Up to remove duplicates
   • Join fragmented lines with Modify > Join
   • Verify all walls are closed polylines

Drawing 2D Plans from Scratch

1. Set the current floor (e.g., Ground Floor)
2. Draw walls using Design > Wall:
   • Click start point and end point
   • Or trace over imported 2D geometry
3. Add doors and windows using Design > Opening
4. Add columns, beams, and slabs as needed

3D Building Model Creation

Converting 2D to 3D

Allplan's 2D-to-3D workflow is straightforward:

1. Walls: Select 2D wall lines > Design > Wall > Convert to 3D Wall
   • Specify wall thickness, height, and material
   • Allplan generates the 3D wall solid
2. Slabs: Select 2D slab outline > Design > Slab > Create
   • Specify thickness and elevation
3. Openings: Already placed doors/windows in 2D automatically cut 3D wall geometry

Parametric Building Elements

Allplan building elements are parametric:

• Walls: Adjust thickness, height, material, layer composition after creation
• Slabs: Adjust thickness, elevation, openings
• Columns: Rectangular, circular, or custom cross-section
• Beams: Rectangular or custom profile
• Roofs: Pitched, flat, or custom with parametric adjustment

Editing 3D Elements

1. Select the element in 3D view
2. The Properties palette shows all parameters
3. Change any value (height, thickness, material) and the element updates
4. Use Modify > Stretch to adjust multiple elements simultaneously

Reinforcement Modeling (Allplan Engineering)

Adding Reinforcement to Concrete Elements

1. Switch to Engineering module (if licensed)
2. Select a concrete element (slab, wall, beam, column)
3. Design > Reinforcement > Bar
4. Specify:
   • Bar diameter: 8mm, 10mm, 12mm, 16mm, 20mm, 25mm
   • Bar shape: Straight, L-shaped, U-shaped, stirrup, custom
   • Cover: Concrete cover (typically 25-40mm)
   • Spacing: Center-to-center distance
5. Allplan generates 3D reinforcement bars within the concrete element

Reinforcement Schedules

1. Design > Reinforcement > Schedule
2. Select all reinforcement in an element or area
3. Allplan generates a bending schedule with:
   • Bar mark number
   • Shape code
   • Diameter
   • Length
   • Quantity
   • Bending dimensions
4. Export to CSV or PDF for the rebar fabricator

Quantity Takeoff

Generating Quantities

1. Tools > Quantity Takeoff
2. Select elements to include (or entire building)
3. Allplan calculates:
   • Concrete volume: Per element type (walls, slabs, columns, beams)
   • Formwork area: Surface area of concrete elements
   • Reinforcement weight: Total steel weight by diameter
   • Wall area: By material and thickness
   • Door/window count: By type and size
4. Export to Excel or PDF

Quantity by Layer

For cost estimation by building section:

1. Assign elements to building sections (e.g., Wing A, Wing B)
2. Run quantity takeoff per section
3. Compare costs across sections

IFC Export

Configuring IFC Export

1. File > Export > IFC
2. Set IFC version:
   • IFC 2x3: Maximum compatibility (recommended)
   • IFC 4: Advanced features (for modern BIM tools)
3. Set Model View Definition (MVD):
   • Coordination View: Standard for clash detection and coordination
   • Reference View: For visual reference in other tools
   • Design Transfer View: Full model transfer with properties
4. Select elements to export (all or filtered by layer/type)
5. Set property sets:
   • Pset_WallCommon: Fire rating, thermal transmittance, load-bearing
   • Pset_DoorCommon: Fire rating, security rating, glazing
   • Custom property sets as needed

IFC Export Checklist

Before exporting, verify:

• [ ] All building elements are classified (wall, slab, column, etc.)
• [ ] Materials are assigned to all elements
• [ ] Building stories are correctly defined with elevations
• [ ] Coordinates match the project survey point
• [ ] Property sets are populated with relevant data
• [ ] No duplicate or overlapping elements
• [ ] File size is reasonable (< 500MB for coordination)

Importing IFC into Revit

1. In Revit: Insert > Link IFC
2. Select the Allplan-exported IFC file
3. The model appears with element classifications preserved
4. Use Revit's Coordination Settings to map IFC categories to Revit categories

Views and Drawing Generation

Creating Floor Plans

1. Views > Floor Plan
2. Select the floor/story
3. Set display options:
   • Visible elements: Walls, doors, windows, dimensions, annotations
   • Hidden elements: 3D-only elements like roof structure
4. The floor plan is generated from the 3D model
5. Add dimensions, annotations, and text

Creating Sections

1. Views > Section
2. Draw the section line on a floor plan
3. Specify viewing direction and depth
4. Allplan generates the section view from the 3D model
5. Add section annotations and dimensions

Creating Elevations

1. Views > Elevation
2. Select the building face (North, South, East, West, or custom)
3. Allplan generates the elevation from the 3D model
4. Add elevation annotations

Layout and Plotting

1. Layouts > New Layout
2. Set paper size (A3, A2, A1, A0)
3. Insert views: drag floor plans, sections, elevations onto the layout
4. Set scale for each view (1:50, 1:100, etc.)
5. Add title block and north arrow
6. File > Plot to print or export to PDF

Wrapping Up

Allplan's 2D-to-3D workflow is one of the things that drew me to the software. Not every project needs full BIM from day one, and the ability to start with 2D and progressively build up the 3D model is invaluable. The IFC export is reliable, the quantity takeoffs are accurate, and the reinforcement tools are excellent. My tip: set up your project template carefully — layers, lineweights, title blocks, and default materials. A good template saves you hours on every project.