Entrant details
Role or Job Title on the Project
Head of BIM Innovation
Employer
Compendium BIM+Kybernetik GmbH & CO. KG, Frankfurt am Main, Germany
Employer Role
Other
Are you or your employer a member of buildingSMART?
No
Submission details
Submitting Party Company Name
Compendium BIM+Kybernetik GmbH & Co. KG
Submitting Party Company Location
Frankfurt am Main, Germany
Submitting Party Role on Project
own Software Development Project, BIM Manager/Coordinator
Submitting Party Company Website
Full Project Name
GUIDfix: fixing GUIDs in HVAC models during openBIM process
Project Location (Country)
Germany
Project Objectives
The aim of the project is to make it possible to trace identical models with GUIDs that are constantly changing in the openBIM process on the basis of internal program functions of HVAC CAD systems.
openBIM Achievements
Models of different quality and geometric representation were transferred into an orderly openBIM process by using GUIDfix to enable consistent tracking of GUIDs.
Without this procedure, the project listed here as an example would only have been possible with considerably more effort (time and manpower) and the associated substantially higher costs.
openBIM used
IFC 2x3, BCF
Software used
GUIDfix, Solibri Office, BIMcollab ZOOM Pro, Simple BIM, C.A.T.S, plancal nova, DDS-Cad, MicroStation TriCAD, Revit, AutoCAD Linear, Nextcloud (CDE), collaboration platform BIMcollab
Highlights
- The specially developed software made the coordination of the HVAC models possible in the first place.
- In addition to the savings achieved by the openBIM process, GUIDfix has enabled a further 15% reduction in working time.
- After a planning delay of about 5 years preceding the openBIM process, almost collision-free models are available after only 5 months thanks to openBIM and the use of GUIDfix.
Project and Stakeholder Logos (compiled into one .ppt/pptx file for upload)
Project Address
Due to NDA agreements there is no further information possible.
Project Type
(Other)
Size of Project
example project with GUIDfix in use: 64.200 m2 BGF, up to 3 lower levels and 11 upper levels
Detailed description of the project
Background
In the course of a openBIM process we receive successive data drops from specialized engineers. Each of these data drops contains a collection of IFC models representing the current state of a project. On these models we conduct collision detection and attach issue markers to colliding components or other technical issues.
Our customers import and export IFC models with diverse software tools. Some changes to the model, e.g. in response to detected issues, lead to re-computation of (parts of) the model which in turn leads to the replacemet of GUIDs of certain components.
When GUIDs are changed between datadrops, attached issue markers from the previous datadrop are lost because they cannot be mapped to components anymore, hence they cannot be used for the most recent models and for further issue management. However, we want to preserve and monitor issues throughout the entire timeline of a project. Therefore we developed GUIDfix as a tool which allows us to keep GUIDs consistent over the entire data drop history. GUIDfix scans the models of two both data drops (previous and current) for those components that have not been changed geometrically.
For each pair of geometrically identical components the GUID is transferred from the model in the previous datadrop to the corresponding model in the succeeding datadrop. Thereby we ensure that geometrically unchanged components do not change GUIDs between datadrops and issue markers attached to components are preserved. GUIDfix enables consistent and reliable issue tracking and the usage of collaborative tools within the openBIM process.
At each datadrop we need to process two large collections of IFC models in order to automatically map corresponding model pairs and within those models find all geometric objects that have been unchanged between datadrops. All those geometric matches are checked for GUID consistency and if needed the GUID is transferred from the older model to the current one in order to preserve GUIDs for unchanged objects throughout the entire history of datadrops. As shown by Fig. 1 („GUIDfix Log Statistics“) in the attachments the amount of geometrically unchanged objects represent the major portion of geometric objects in the IFC models we processed. Given the size of our models and the frequency of data drops we could not solve the problem by pairwise comparison of geometries in both models, since this would obviously result in a runtime complexity which would make the tool practically unusable. Hence, we developed an algorithm which maps geometrical shapes to numbers. Based on those numbers we are able to determine whether geometries have changed. Component identification, mapping and GUID transfer between models is then based on global placement and geometric identity within certain bounds.
Potential for further development
User Interface and different usage scenarios
We plan to develop more sophisticated user interfaces and usage scenarios for GUIDfix and also to develop the tool as a network based service in order to fit individual needs of users. Both desktop applications, plugins for third party software systems and server client based solutions could be feasible.
Geometry Diff
In perspective, we implemented a tool that scans a pair IFC models for their geometrical difference. On top of this, a more sophisticated viewer for geometric difference of models and even a custom version control system can be implemented. Further analytic tools could possibly be attached to this.
Clearing redundant geometries
A significant number of entities appear with redundant geometric representation in input models.
In this case we cannot deduce which GUIDs in the old model correspond to which geometry representation in the new model. We see the need to clear such redundancies from IFC models in the future.
Detailed description of openBIM on the project
The existing building was digitally recorded by the surveyor and re-modelled. The IFC model derived from this has its origin in the georeferenced location. The files of the planners are referenced with their zero point to the original 2D planning. This zero point discrepancy between the architectural model and the building services models meant that the existing building had to be rotated and moved in the inspection software (SimpleBIM). In order to check the exact positional accuracy after the shifting, 3 test objects were created, which refer to the zero point of the planning models and are each oriented to a building corner on the roof. If the test objects lie directly on these corners after the displacement, the positional accuracy of the existing model is verified.
The building services models are also checked for positional correctness. For this purpose, COMPENDIUM creates a zero point component (also coordination component). This object consists of eight fitting pieces, in whose contact point the project zero component with coordinates (x, y, z) is located.
The zero point component is classified and made available to the object planner as an IFC file with craft-specific fitting components. COMPENDIUM loads the complete zero point component as inspection elements. The planners' fitting components must fit completely into the zero point component. This ensures that the models are positioned correctly. This is checked as the first rule in Solibri.
Due to the size of the project (approx. 3,6 GB data exery cycle), the building parts were set up and checked in Solibri in separate files. In addition to the 4 buildings, an extra file was created for the technical centres. Each of these files contains the HVAC models, the as-built model and the model of the test components.
Overlaps between the individual building parts are again checked in separate files with simple rules.
Every second week the IFC models are stored on the Nextcloud (CDE) by all planners. The files are given a new extension that refers to the current datadrop and after COMPENDIUM has checked for completeness, a GUIDfix is performed for all models. These fixed files end up on the platform and are the basis for checking in Solibri and tracking in BIMcollab.
In Solibri, the old files are first replaced with the current, fixed files. The fixed GUIDs make it possible to track the existing issues and comment on or close them in Solibri or BIMcollab.
To enable the planners to edit the issues, COMPENDIUM has set up a BIMcollab zoom file, similar to the Solibri files, in which all the respective models are linked. These bcp files are accessible on the Nextcloud (CDE) for all planners. With the GUIDfix it is possible to locate issues from older datadrops there and edit them in the native programs.
Software ecosystem map
openBIM Supporting Evidence
Benefits from using openBIM
In the course of the large renovation project, the planning was initially carried out in the conventional way. Due to the great complexity of the building complex, particularly with regard to the technical equipment, there was a planning delay of approx. 5 years and constantly increasing cost forecasts at the time of implementation of the openBIM process by COMPENDIUM. Some shafts were occupied several times. The planning of the various disciplines collided both with the existing structure and with each other in numerous areas. The numerous collision points were hardly manageable in the classic way.
The various HVAC disciplines were available as 3D planning, not BIM, in a total of approx. 500 models from 5 different software systems. Within 4 weeks a special openBIM process was developed, tested and implemented. The CAD systems used in the project change the element GUID after processing the individual components. However, a consistent GUID is required to uniquely identify each object and to connect it to the relevant errors. In order to track issues and speed up the process, GUIDfix was developed and deployed within 2 weeks. The result is an almost collision-free model after only 5 months of BIM.
"We were able to innovate using openBIM."
By using GUIDfix, HVAC disciplines can be reliably coordinated with each other. This leads to an acceleration of coordination processes, reduction of planning effort and reliable issue tracking.
"We were able to identify where we need openBIM to develop further."
The element GUIDs, which are constantly reassigned after components have been changed and recalculated in CAD systems for HVAC, severely impede the openBIM process. Since the preservation of element GUIDs throughout the entire process is currently not guaranteed by the authoring software, special software solutions such as GUIDfix are required to ensure a proper openBIM process.
BIM Uses were defined on the project
I agree to be contacted about the project BIM uses outside of this awards program.
Stakeholders
COMPENDIUM BIM+Kybernetik GmbH & CO. KG, Frankfurt am Main, Germany,
https://www.linkedin.com/company/compendium-bim-kybernetik/, BIM Manager / Coordinator / Software Developer, Torben Wadlinger
