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Webinar Recap: VICUS Buildings in 30 Minutes
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Stephan Hirth On 23 April 2026, Christoph Morbitzer and Dirk Weiß walked through the key features of VICUS Buildings in 30 minutes as part of our release campaign. The recording is now available on YouTube.
Watch the recording
What was covered
In about 30 minutes the core feature areas of VICUS Buildings were demonstrated live in the tool:
- Geometry input via IFC import and direct modelling in the 3D editor
- Zoning and usage profiles based on DIN V 18599 and custom templates
- Constructions and material database
- Shading with an interactive sun-path diagram
- Dynamic annual simulation with hourly results
- Evaluation of heating and cooling loads, energy demand and thermal comfort
Questions from the audience
The chat received a number of technical questions during the webinar. The original questions are reproduced below (translated from German, typos silently corrected) and grouped by topic, with our answers.
Modelling and geometry
Which plan formats can be imported?
Supported formats are IFC, DXF, Shape and PDF. PDF and raster images can be placed as background plans, on top of which walls and rooms are then captured semi-automatically. Importing E-CAD models is possible indirectly by exporting an IFC file from E-CAD and importing that into VICUS Buildings.
Can existing plans (PDF, ideally) be imported automatically?
PDF plans are embedded as background images. Fully automatic vectorisation is not part of VICUS Buildings — capture is done semi-automatically in the editor.
E-CAD import?
There is no dedicated E-CAD import. The typical path is via DXF.
Does the IFC model need to be cleaned beforehand?
Not strictly. VICUS Buildings ships with an integrated IFC reader that detects and visualises typical inconsistencies (overlapping walls, missing spaces, invalid geometries). Clean model quality nevertheless improves results noticeably.
How are zones defined?
Zones can be inherited from IFC spaces, created manually in the 3D editor, or derived from storeys and room groups. Several rooms can be merged into one thermal zone.
Is IFC export possible?
The current focus is on import.
Building physics and constructions
What are the differences between the current version of VICUS Buildings and the old, free SIM-VICUS?
VICUS Buildings originated from SIM-VICUS but has by now substantially diverged from it — the VICUS Buildings codebase is roughly twice the size today. Additions include professional support, continuous maintenance, significantly extended IFC and plan import, expanded building services (beta), the interactive sun-path diagram, an FMI 2.0 interface, and a thoroughly reworked user interface. VICUS Buildings is free for teaching — students can obtain a free license on request, including for thesis work.
Can databases from other software be imported, e.g. ZUB Helena?
VICUS Buildings has its own construction and material database. A direct import from ZUB Helena is not implemented. Wall assemblies can, however, be imported via the open XML format — also automatically or via scripting.
Hobbyist-friendly interfaces would be interesting, e.g. generating wall assemblies with AI and integrating them into the database — XML import for wall assemblies?
Exactly the use case for the XML format. Wall assemblies, constructions or load profiles can be generated externally — with AI agents, scripts or custom tools — and imported cleanly into the project database via XML.
Can VICUS Buildings also simulate multi-dimensional heat flow / thermal bridges?
Thermal bridges are currently not modelled in VICUS Buildings. For detailed 2D/3D-coupled simulation of individual thermal bridges, the sister product DELPHIN is available — sharing the same TU Dresden background.
Interior insulation with moisture?
Hygrothermal simulation of individual components (interior insulation, moisture protection, mould risk) is the domain of DELPHIN. VICUS Buildings itself runs purely thermal simulations.
Wow, the shading and sun-path diagram is very impressive. But vegetation isn't included …?
Vegetation is not modelled as a dedicated object class. Trees and hedges can, however, be modelled as shading geometries (blocks) and are then taken into account by the interactive sun-path diagram.
Building services
Can VICUS Buildings simulate the interaction of PV systems and heat pumps?
Heat pumps and PV systems can already be modelled directly in VICUS Buildings — building services are currently in beta / test phase. In addition, VICUS Buildings exposes the building's load curve and net energy demand as an interface, so that for example final energy demand can be derived via an estimated heat-pump COP.
Is DHW (domestic hot water) accounted for?
Domestic hot water is part of the building services modelling, which is currently in beta / test phase.
Can custom system models be created?
Building services can already be modelled directly in VICUS Buildings — this functionality is currently in beta. In addition, external models can be coupled in fully via the FMI 2.0 interface, for example plant and control models from Modelica/Dymola.
Climate and weather data
Are Austrian climate datasets planned?
Climate data for Austria (Test Reference Years and station data) can be imported in EPW format.
Climate-change scenarios as well? (in the data import context)
Yes, by importing climate projection datasets (e.g. future Test Reference Years).
How is air infiltration handled in your tool?
Through zone-wise air change rates, either constant or time-dependent.
Simulation and validation
Which thermal simulation model is used under the hood?
A numerical multi-zone model with transient heat balance across wall layers and room air, plus radiation/convection splitting.
What about validation?
The software has been thoroughly validated through the SimQuality project, funded by the German Federal Ministry of Economic Affairs (BMWi). BESTEST validation is close to completion; remaining deviations are marginal. More on this in our article on validation standards.
As an energy consultant, I'm interested in building simulation for realistic energy demand estimation. The steady-state balance method (DIN 18599) commonly used in energy consulting regularly overestimates energy demand by a factor of 2 or more. Is building simulation better here? (residential, single-family / multi-family houses)
Generally, yes. The steady-state balance method works with normative boundary conditions and very conservative assumptions. Dynamic simulation with real weather, usage and system data at hourly resolution achieves much better agreement with measured consumption — especially for retrofits and residential buildings with individual occupant behaviour. See steady-state vs. dynamic.
So detailed dynamic heating-load calculation is possible?
Yes. Design days and selected cold weeks can be computed dynamically so that heating and cooling loads are derived under realistic load superposition — complementing static calculation according to EN 12831.
Certification and scope
Can usage profiles be imported or reused from DIN V 18599?
Yes. DIN V 18599 profiles (residential, office, school etc.) are bundled. Custom profiles can be loaded via CSV or XML.
Is the program authorised to produce certifications?
VICUS Buildings is primarily a simulation and planning tool, not a balance-method tool according to DIN V 18599. Dedicated balance-method tools are still required for GEG certification.
iSfP print application for residential buildings? / Is producing energy performance certificates possible?
No, since VICUS Buildings is not a balance-method tool according to DIN V 18599.
Interfaces and extensibility
Are FMI interfaces supported?
Yes — the FMI 2.0 standard is fully supported. Every input and output variable of the building model can be exposed through the FMI interface and coupled with external models, for example plant and control models from Modelica/Dymola.
Are there prompt templates for custom AI agents — i.e. how they should generate things?
Since the input format is fully open XML, wall assemblies, constructions or load profiles can be generated with external scripts or LLM agents and then imported. There is no integrated prompt interface today — but we are working on example prompts and templates for common tasks.
Next steps
- Try VICUS Buildings free for 30 days
- Book a personal demo with our team
- Learn more about VICUS Buildings features
If you have a question that was not answered during the webinar, feel free to reach out via our contact form — we usually reply within one working day.
Ready to try it yourself?
Experience VICUS Software live — in a personal demo or download it right away. Sustainable planning starts here.