Capitalize on the Collaboration between Architectural and Structural Software for Complex Projects

Transcription

1 Capitalize on the Collaboration between Architectural and Structural Software for Complex Projects Paul Boireau - former employee of Boll und Partner, now director of BIM Solutions Centre Jochen Tanger - Autodesk SE2880 In this class, you will learn how to manage a high-profile project where the collaboration between the architect and the structural engineer is essential. We will show the key features for successfully creating an Autodesk Revit Structure model from a Rhinoceros architectural model using free forms. Special emphasis will be placed on meeting the challenges of creating high-quality documentation with non-standard Revit 3D elements. We will present tips and tricks to show how it is possible to simplify the design and its documentation thanks to the extensions for Revit Structure and the BIM tools developed by SOFiSTiK. Learning Objectives At the end of this class, you will be able to: Understand how to manage a project with Revit Structure, Rhinoceros, and Sofistik Overcome the key issues that occur when modeling complex geometries Ensure that your deliverables meet your quality standards Analyze your project for the structural analysis with Sofistik Automate time-consuming tasks thanks to the BIMtools from Sofistik About the Speaker Paul Boireau: With experience working with BIM technology since 2005, Paul has acquired high technical skills to help companies develop their BIM capabilities. Thanks to this knowledge, he is now director of BIM Solutions Centre and is looking at developing the BIM business in Europe and the Middle East. He earned a master s degree from the ESTP in Paris (France), and a master of science from the Newcastle University (U.K.). Paul worked as a BIM implementation specialist in the South Asia Pacific region before moving back to Europe when he was then employed by the engineering structural company Boll und Partner and worked on the Leuphana project. paul.boireau@bimsolutionscentre.com Jochen Tanger: based in Munich, Germany, Jochen has been working at Autodesk as Technical Sales Engineer for more than eight years. Since Autodesk decided to market Revit Architecture in Central Europe in 2004, he presents, sells, trains and supports it to resellers and customers. Today he is also responsible for Revit Structure, QTO and all other BIM solutions. Jochen holds a Master s Degree in structural engineering from the University of Lüneburg. jochen.tanger@autodesk.com Notice: all references to the Leuphana project in this document are the sole intellectual property of either Studio Daniel Libeskind or Boll und Partner.

2 Introduction: The project International collaboration Designed in 2008 by world-famous architect Daniel Libeskind, the Leuphana University is a high-profile project due to its innovative and futuristic design. The project is located in Lüneburg, north of Germany and consists of four structurally challenging buildings that provide state-ofthe-art facilities to students. The Chrystal building is at the center of the building and connects to the other parts of the university center: Auditorium, Student Center, and Arts Center. All buildings have a rather unusual geometry that was designed by Studio Daniel Libeskind in New York. The main challenge on the project came from its unusual geometry, having the main structural elements slanted in most parts of the buildings. Reese Lubic Woehrlin Architects in Berlin were contracted to develop the overall design drawings while the structural engineering company Boll und Partner in Stuttgart are responsible for the structural design and its documentation. Right from the start, challenges arose from the international aspect of the project. The working language was set to English but the final documentation had to be in German to comply with local standards. Several pieces of software While communication between partners was an issue, coordinating the relevant information also proved to be challenging, having each partner use a different piece of software for their design and documentation. When Studio Daniel Libeskind used Rhinoceros to design the envelope of the buildings and create their main components, RLW Architects were using Archicad and Autocad to develop their documentation. Boll und Partner decided from the start to use Autodesk Revit Structure to model and document their structural design. The structural engineer s point of view When Boll und Partner first stepped into the project, they were still one of the few companies using Autodesk Revit Structure in Germany. They benefited from the technical expertise from their local Autodesk reseller Hafner s Büro and the project soon attracted Autodesk s attention. It was then selected to be a customer success story in Since then Boll und Partner and Autodesk have kept an ever closer relationship to identify what key issues arose when modeling such a complex structure with Autodesk Revit Structure to improve the software in the future. The following presentation features a summary of the Leuphana project that is still under completion by Boll und Partner. They are now in the detailed design phase for a final completion of the design works expected mid next year. BIM Solution Centre supports Boll und Partner in all BIM related issues during the project. 2

3 Model from Rhinoceros with Autodesk Revit Structure Complex Geometry Four different buildings had to be modeled at the same time. Each of them has challenging structures, the Arts Center being the most difficult one to design with its cantilevered structural steel construction. Most main structural elements are slanted in all buildings to the exception of the core walls. This meant particularly difficult calculations for the Chystal building, which also had to be modeled in 3D in the analysis software Sofistik. Four different Buildings Chrystal Arts Center Student Center Auditorium 3

4 Model Elements How do you model in Revit, without access to an IFC file, or without a Revit file? Well we soon realized we would need a copy of the architect s model to be able to export part or the entire model ourselves in the format we wanted. After a few tries exporting the Rhino model to different formats (DWG, DXF, DGN, SAT and SKP), we came to the conclusion that the SAT format was the one giving us the best result. Facade walls Since they are structural and slanted, Revit wall elements could not be used. It is indeed not possible at the moment to create a wall with an angle in Revit. The only option was to model walls as in-place extrusions. This choice had a lot of negative consequences later on during the project, when an exploitable model for the structural analysis was requested. Slabs Because of the slanted walls, some slab edges had to be slanted too. There were three options to obtain a satisfying result: Slab with connected geometry (cannot be too wide) Slab with in-place extrusion (time-consuming) In-place slab (exact geometry, but need right layouts) The in-place element option was again selected, because it gave us more control on the geometry. 4

5 Columns Slanted columns are possible in Revit and were used in this case. Beams There are a few beams in the project, mostly for the roof construction of each building. Roofs No architectural roof was requested in the model, but the structural walls had to be cut in the right way to reflect the architect s special design. Foundations Foundations were modeled with in-place elements mainly because of the in-place walls and columns, but also because of their unusual geometry. Stairs Stairs were also modeled with in-place elements. Model Consistency and coordination Worksets In this project, worksets were used for several purposes. First, it is useful to use them to reduce the file size. Worksets have proved to save a fraction of a normal project file. They also allow you to have different users working at the same time on the same project. In this case we divided the worksets into two types, first the ones that are linked to the different buildings: Chrystal, Auditorium, Student Center, and Arts Center. We then used a second type of worksets for our project-specific needs. A functionality that we used was the ability to hide a workset by default in all project views. Thus having to display it only in the views where it is really requested. For example we used a workset to store the cylinders that cut the walls in the roof area since we do not need to see them in every view. This feature was really useful when it came to display the 3D linked model from the architect. Since we did not receive an IFC file, we could not control the visibility of elements through categories. Displaying the 3D model would have been a hassle without the ability to hide it by default in all views but to leave it visible in the 3D views we really needed. Otherwise we would have had to keep turning it on and off not only in 3D views but also in 2D floor plans. View Organization Having to work with an architectural model and a set of architectural drawings incurs creating a lot of views. Without a proper management of those views, the project browser can quickly become a nightmare to navigate through. We made sure we named them properly, and also separated working views from the ones ending up on a drawing. This significantly reduced the time spent browsing through the views since we knew what our working session was aimed at. We could then decide to reduce the field allocated for one of both categories. 5

6 Create a model for the Structural Analysis Not all parts of the project needed to be modeled in Revit and exported to the Analysis Software Sofistik. Only the Chrystal building needed to be exported because of its complex geometry. Preliminary design Revit 2010 At the time the interface between Revit and Sofistik was allowing us to export Revit elements like walls, slabs, columns and beams. But this was only possible if those elements were standard ones. This did not work in our case because we used in-place elements to create our façade walls and slabs. Those elements are only geometrical forms and do not contain any analytical information that is useful for a calculation program. Revit gives you nonetheless the ability to add analytical lines to any form by simply drawing them wherever needed. The interface exporting the model to the Analysis package would just have to recognize this information and pass it on. This was unfortunately not the case at the time with Revit 2010 and the corresponding version of Sofistik. This meant that we could not use walls and slabs as they were in this state. We could have decided to export the model to a simple DWG format and then read it directly in Sofistik but the adequacy of the model was too approximate in some parts at a fine level. We then took a step back and reconsidered what we wanted to do in Sofistik. In this software, walls and slabs are actually the same kind of elements, they are considered as panels. Modeling a wall or a slab does not really matter that much. Knowing that slabs can have angles in Revit, we made the most of this functionality and recreated all walls with slabs. There are then two ways to obtain the right slope: either by amending edges or end points of elements manually in height, or by using a sloping arrow. When amending manually the slab edges or corners, it is possible to obtain the right geometrical result, but the analytical information is somehow stuck to a specific level in Revit. This is why we had to use sloping arrows to get our angled slabs. There was still one problem left: because we cannot control the accuracy of the angle to a high level (Revit allows 4 decimals for the angle input), this process still left inadequacies where elements where joining. This problem was thankfully solved by the tolerance in Sofistik. Even though we could see elements not joining perfectly in Revit, they would actually be fine in Sofistik. Having the right geometrical information, we could then analyze our model and design all walls. Detailed design Revit 2011 For this phase, the new version of the interface between Revit and Sofistik was tested. Substantial improvements had been made to the API program dealing with the exchange process. It then allowed us to draw additional analytical lines on top of our in-place walls. The same procedure was then applied to slabs. The model creation was extremely faster than during the preliminary design. 6

7 Integrate SOFiSTiK and its BiMTOOLS The SOFiSTiK BiMTOOLS are a set of free Revit Structure plugins that help being more efficient when producing drawings (especially formwork drawings). The workflow efficiency can be increased by up to 50%. At the moment the BiMTOOLS are only available for the German version of Revit Structure. More Information is at: Templates Customization of templates for the German Market (DACH) Substitution of Font Type This tool will change the font properties of any 2D annotation (notes, dimensions, wall tags, beam tags, column tags, etc.) in a Revit project either for all annotations or part of them thanks to selection filters. Positioning of Elements Family Creator With this tool you can apply a position number to elements of the same category. It is possible to select a prefix for each category and define the numbering order. The format of positioning is flexible. You can for example add the level information to the position number. With the family creator you can create custom families for beams, braces and columns. These families allow a better integration with other Sofistik products. With this tool, the shape and material for each family can be chosen. 7

8 Automatic Dimensioning With this tool you can apply dimensions to elements in a very efficient way. The function creates several dimensions at the same time. It avoids having to manually measure elements one by one, saving the Revit user a substantial amount of time. Create Views of Elements With this function you can create specific views in a simple way for any element in Revit regardless of its orientation. First you define the orientation of the view and the tool creates then a specific view and places it on a sheet. Read out of Insertion Points This tool will create a list of insertion points for specific elements. With this information you can mark the insertion points directly for use on the construction site. The user can select in which coordinate system the data should be exported. After this step it is possible to use this data with additional systems (e.g. measurements). 8

9 Control the quality of the deliverables Deliverables For this project, we had to produce a set of preliminary drawings that would describe the structure. Quantities In order to obtain the quantities from the model, we had to make sure that elements were attributed to the right category. Revit does not give you the ability to create a schedule of generic models. Since most walls and slabs were in-place elements, we had to control that they were modeled as such and not as generic models. We then split elements to have different schedules. A good way of making sure we had the right elements in the relevant schedule was to create a 3D view for each schedule. 9

10 Phasing To describe the construction, we used a set of colors to differentiate every phase of the process. All elements had therefore to be modeled as they would be built or assembled on site. This meant that walls and columns had to be split per level. 10

11 Specific German standards In a lot of countries, drawings are produced looking down to the structure. In Germany, and in Europe in general, drawings are produced looking up to the slab above the current level. Both levels and bearing elements need to be shown and differentiated on drawings. To obtain such a result it is possible to display elements that are not in range with different colors and linetypes thanks to the object style command. Unfortunately this is only valid for lines and not for hatching. Since we need to apply a different hatching pattern to elements on top of the current level, this is not a viable option. To solve this issue, we create different views for various purposes that we then set on top of each other on the relevant drawing. To make sure we obtain the right results, only one view can be shown with the hidden lines property. The other views on top need to be displayed as wireframe so that they do not hide the main view. This enables us to get the right results but also creates unexpected problems. Revit was indeed originally designed for countries adapting a looking down approach. Once you change the view setting to looking up, some elements do not display as they usually would. Conclusion Thanks to the link existing between different pieces of software, it is possible to go faster and more accurately in the design of complex structures. The exchange of information is neither smooth nor error-free, but the advantages of reusing the same information for different purposes along the life the project certainly has its advantages in terms of precision and time savings. 11