By Povilas Sindriūnas, AGACAD Architectural Engineer & BIM Application Engineer
Project success largely depends on thorough BIM model management. The response from industry professionals has made it clear that regular model maintenance can help improve efficiency, reduce loading time, and minimize time spent chasing loose ends. In part I we discussed how to keep good model health in check using Revit's Inbuilt Warning System and Audit Tool. In part II we’ll look at other no-less important aspects of model management and efficiency.
Helpful Revit Modelling Techniques
To make the most out of collaboration-enabled projects, each team member should be familiar with the following modelling techniques to help reduce unnecessary clutter in Revit project files.
In-place family use
- In-place families are designed for elements that can’t be modelled without project context and are not intended for general modelling.
- Making copies of an in-place family to create a slatted wall, for example, creates new family types, in turn bloating the model. This can be done by creating a simple curtain wall instead.
- Content left over from previous options/designs bloats the model.
- Regular purging of model to reduce file size and increase model performance.
- Removing obsolete families from the model also helps performance.
- Purging will remove unused views, families, and other objects from the project, thereby reducing file size.
- If the project is workset-enabled, all worksets must be open to use this tool.
- Remove obsolete design options.
- Make sure unused and obsolete design options are not set to primary.
Room and space volume calculations
- Model performance severely affected for larger projects.
- Switch off volume calculation from Revit settings until it is required for exporting the information.
- Model and view performance are affected for larger projects. It is commonly caused by importing DWG files with line styles, layers, hatches, and subcategories into the model.
- Best practice is to link DWG files.
- It is best to import to current view only and not in all views.
- Try to keep exploding of DWG files to a minimum and only when necessary.
- Remove obsolete DWG files from the project.
- Worksets are a mechanism to subdivide your model by grouping elements based on a particular function or area within your model rather than categories. Subdivisions of model can be horizontal or vertical.
- Worksets form a part of the collaboration tools within Revit. They can improve performance, data handling and sharing.
- Utilize worksets for greater visibility, control and faster performance.
- Turn off worksets that aren’t required for the modelling task at a given time.
- Revit already has one way of managing object visibility and classification. It’s done by categories – Visibility/Graphics Overrides window.
- Worksets can also be used for linking other models to your central file and gaining more control over the link.
- Too many levels make modelling harder.
- Only use the minimum number of levels and offset all elements from levels.
- If a level is deleted, all elements hosted on that level will be deleted without warning.
- An excessive number of groups affects model performance, especially with room separation lines included and walls that need to interact outside the groups.
- Instead, consider linking larger groups or creating super-families.
- Grouped arrays of elements badly affect model performance.
- Raster images are embedded within the project file and can slow load times; this applies especially to title blocks.
- Purge if not required or change DPI to an appropriate value.
- Views not placed on sheets affect model performance negatively.
- Use “Not on Sheets” browser organization to gather free views in one place.
- Delete unnecessary views regularly.
When modelling, people tend to take shortcuts for the short-term benefits. However, it’s worth spending the extra time and effort to implement good methods and practices. Establishing clear guidelines and providing your staff with support will increase productivity and efficiency both in solo and team-based projects. It will help reduce errors when exporting information or sharing models with other consultants, clients, contractors, or asset managers.
In Part III of this series on Revit Model Management, we will overview the most important factors that can result in a faulty BIM model and will share additional ways to up your Revit game.