IFC to LandXML Surface Extraction
Turn the parts of an IFC design you need into LandXML surfaces for civil review and CAD. Select elements, classes or property groups, then extract each course separately or merge a selection into one top surface. The new layers appear in your project next to the IFC and the survey, ready to inspect and download.
- Input
- IFC model layer
- Select by
- Element tree, IFC class or property
- Output
- Derived LandXML TIN in metres
Example
A road design delivered only as IFC
A contractor receives a road design as an IFC model. Each pavement course is a set of elements carrying a property with the course name, but the model tree is organised in a way that makes the courses hard to pick out. The site team needs a LandXML surface for each course to compare with the survey of that layer.
The engineer groups the elements by the course property and runs Export LandXML, merging each group into one top surface. Each group runs as its own job, so four courses give four LandXML layers in the project. Before comparing them with the survey, the engineer checks each surface against the IFC, paying particular attention to kerbs, retaining walls and places where courses overlap. Any surface intended for machine control is also checked in the receiving system.
- Input
- IFC road model
- Grouped by
- Course name property
- Output
- One LandXML surface per course
Choosing which IFC elements to export
Open Export LandXML on an IFC layer (you need editor rights on the project) and scope the export in one of three ways.
Element tree
Pick elements or whole branches from the model hierarchy. Quickest when the model is already organised the way you think about it.
IFC class
Take every element of a class, such as slabs or pavement courses, when the class alone tells you what you need.
Property groups
Group elements by the values of a property, such as a course or layer name. Each group becomes its own export job and its own LandXML file.
What ends up in the LandXML surface
SkyGIS looks for the exposed upper parts of the selected geometry, removes vertical and near-vertical faces and discards lower faces hidden underneath. Shared points and duplicate geometry are cleaned up before the result is written as a triangulated surface in metres.
Choose per-element output when each element needs its own surface, or merge a selection into one top surface. Where merged elements overlap in plan, the upper surface wins. Export stacked pavement courses separately so a higher course doesn't hide a lower one.
The LandXML is added to the project as a layer so you can inspect it alongside the IFC and survey before using it in a comparison. You can also check the downloaded file in the CAD or machine-control software that will use it.
From IFC selection to civil surface
Select the geometry
Choose elements, classes or property groups and name each output. Keep separate pavement courses in their own groups.
Extract and inspect
Run the export and review the LandXML layer alongside the IFC and survey. Check position, levels and the edges of the selected course.
Download for the next step
Download the surface for CAD, quantities or machine control, and confirm its units and placement in the receiving software.
Questions
What if the design only arrives as an IFC model?
SkyGIS Pro extracts selected upper surfaces as LandXML TINs for road courses and earthworks workflows. Choose the elements or group them by course, then review the generated surfaces in the project.
Can I use the extracted LandXML for machine control?
Yes, after checking the extracted surface in your receiving system. Confirm the design level, boundaries, coordinates and units before using it for machine control or setting out.
What happens at vertical walls or overhangs?
The extraction keeps the upper exposed surface and leaves vertical and near-vertical faces out. Review edges around walls and overhangs, where a terrain surface may need adjustment or a different selection.
Does IFC to LandXML keep the solids and properties?
No. The output is a derived top surface. Solids, vertical faces, hidden lower geometry and IFC properties don't carry over.
Can I export several pavement courses at once?
Yes. Group the elements by a property such as the course name, and each group runs as its own export job. Keep different courses in separate groups: merging them together keeps the upper surface where they overlap.
Extract surfaces from your own IFC
Bring an IFC design to a 30-minute walkthrough. We'll select the courses you need, extract their surfaces and review the results together.