Based on the specialist plans. The advantage of this solution is that the building is virtually built using the actual plans’ content, therefore possible deficiencies may be discovered (for e.g.: an opening has different dimensions or positions on structural layout and on formwork plans; content of the vertical mechanical pipe plans differs from layout; not every item shown on the architectural plans has a connection to the network, etc.). Therefore we rebuild the model using the plans, regardless of which specialists build their own model. This is only way for us to determine gaps and anomalies, and this is how the model will be suitable for creating the bill of quantities at construction stage.

We work above LOD 300 level (Level of Detail/Level of Development). So LOD 300 refers to our model’s level of details, while the RevBIM 3D model is broader, has more detail than a LOD 300 model, and is used for collision detection. The RevBIM 3D model is detailed enough for the junctions (naturally not down to every thread), therefore the models can be used to determine the quantities that are usually precisely defined at the junctions, for e.g. the necessary plaster on the window and door openings, extra facade insulations (2-5-8 cm thick), and so on.

Our colleagues have built BIM models for more than 1.000.000 m2 of buildings.

Data content of the model for collision detection and bill of quantities is around LOI 200 (Level of Information). If requested by the client, this can be increased to LOI 300, however, it is unnecessary for the purpose of collision detection and bill of quantities

Structural design: Modelling cast-in-place structures and formworks. Quantities in line with the bill of quantities’ details. (Steel rods are not modelled and quantified.)

Architecture: Modelling to the level of junctions. Quantities in line with the bill of quantities’ details.

Building mechanics: Cables, air vents, pipes, fittings, devices. Quantities in line with the bill of quantities’ details

Electric: Cable tray, switch box, transformer, floor box, luminaires, fire alarms and other fittings. Quantities can be modelled in line with the bill of quantities’ details. (Cables and automation are not modelled and quantified.)

The structural part is built first along with the formworks, followed by expanding the model with the architectural, mechanical, electrical and other (landscape/utility/road) elements.

A different sequence is possible, but we recommend to have the structural part created as a first step, and then compare the building mechanics and penetrations with the architecture. In general, if the client wishes to advance the tendering phase on a certain building part (for e.g. masonry), than we will adapt as much as possible during modelling and advance the bill of quantities of the requested area.

The model may be built parallel to the construction plans, or a bit lagging behind based on interim plans. In this case, the starting point is the first large package of plans. We call this continuous building and collision detection.
The other possibility is modelling from the entire planning documentation, at once. In this case the model is built based on the plans submitted to the client for approval, and then the designers make amendments to these plans based on client remarks and the collision detection.

We need the specialist plans in .dwg/.pla format.

It is easiest to have all plans that are included in the plan submission; this way we can note if a plan is missing, that is necessary for modelling.

JBased on the past few years’ of experience, the designers are not up to building such a detailed model at the moment. Designers do build models, they also sometimes call it BIM modelling, however, the details of these (for example the architect model’s) are only enough to facilitate creating the facade plans and cross sections for construction phase. Junctions and detail drawings are still prepared in 2D by the designers, therefore this data content can’t be included in the model, which therefore is only sufficient for determining quantities to a limited extent. Building mechanical models are usually limited to main pipe lines, if there is any modelling at all. Branches and connections are nearly never part of the building mechanical model, therefore the feasibility of the pipe layout with all connections shown on the 2D plan is not verifiable, and also can’t be used for determining quantities.

Determining the quantities becomes questionable if a model is “expanded” by a designer. We do not determine quantities base on a model that was prepared by some else, because that might not be in line with our model building standards. In this case we can’t check the data content of the plans, or verify the differences between the received model and the plans. For example: Mechanical designer models the main specialists at first, but does not follow up the amendments.

The one who prepares the budget call (usually the subcontractor of the specialist or of the principal designer) does that to the best of his or her abilities. But since this call is based on calculations and derivations, with possible guidance from the engineering chamber, it contains significant extra quantities (for e.g.: plaster quantity equals to the wall surface multiplied by a factor). On top of this, the call also contains some waste quantity for certain material types. As a result, the call does not contain the accurate material quantity in the building but still, the designer can’t be held accountable for that. Quantities derived from BIM modelling are always the realistic amounts built in.

The price of BIM design, including the above mentioned deficiencies, is generally higher than normal design fees. It is an accepted tendency in many countries in the world, that BIM modelling and hiring BIM management is mandatory for state investments, with a separate budget, who are responsible for detecting collisions and having the designers do the necessary amendments. In other words, it is acknowledged, that generally the designs will include collisions due to the complexity of the buildings (may those be architectural solutions, mechanical requirements, or else).

In case of building mechanics, all pipes are modelled in their entire length, in other words, not only the main pipelines are modelled, but the branches too, up to sanitary units / fittings.

We continuously share our remarks during model building in an Excel sheet including relevant specialists, plans, floors, etc. A remark remains open until the related plan is modified, ensuring that all necessary amendments are done. Then we revise our model with the new input and see if any other collisions or remarks were created.

Collision detection is performed manually during model building, and automatically at certain intervals.

This highly depends on the building dimensions and the design’s details, but an average of 80-120 remarks are usually made for a building of ~15-25.000 m2 floor area. It is important that the 80-120 remarks only refer to those that can actually cause a problem during construction. Automatic collision detection, depending on its setup, can also show collisions that are normally dealt with during construction. An example would be the collision of small diameter pipes, that are usually manually bended on site during installation, but is highlighted by the automated collision detection, and can use up designer resources from the significant problems.

The bill of quantities is always tailored to the client’s needs, even if it deviates from the principal call (for e.g., apartment divider, utility barrier, facade, corridor and partition walls can be listed separately, along with their surfacing, which enables a quick change in building material if needed).

It is possible to list the quantities on the bill of quantities’ level per building or per floor, even using different filters, based on the model that we built as per the offer’s data content. Therefore it is suitable for cost-controlling during construction.

The model is always built using the latest ArchiCAD available at beginning. As a contractual partner of Graphisoft, our license is continually tracked and renewed, which guarantees the latest and most state-of-the-art software framework.

The model is submitted in IFC format in line with international standards, and/or in BIMx format, which is Graphisoft’s own free format. The principal and specialist designers also receive the model, and therefore can check if the model corresponds to the planning. The data content of the model is the responsibility of the specialist designers. Upon request, the model can be submitted in ArchiCAD format, too.

Naturally, training is possible. It also depends on the software the client uses. At the moment the entire BIM model is created in the latest ArchiCAD.

The overall saving is made up of recognizing and correcting the collisions at the early design stages, and of using the construction level bill of quantities during tendering and ex-post clearing. These two can add up to even 5-10%-a of the total investment cost.

The model can be suitable as an input model for facility management systems with further data upload. For this we need to know what kind of the system the client wants, and what type of data would be uploaded.

You can find residential buildings, residential parts, hotels, malls, multifunctional buildings, factories and even warehouses among our references. On top of our Hungarian references, we also have references from Slovakia and the Czech Republic. At the moment are ongoing projects contain buildings of above 140.000 m2 total floor area.