REVIT MODELING INDIA Best Practices of Revit Family Creation Author: Premal Kayasth BIM Evangelist
Introduction: The white paper aims at defining best practices and procedures to be considered at the time of Revit families creation in all the three disciplines i.e. Revit Architecture, Revit MEP, and Revit Structure. The best practices covered in this document are lessons learned by our BIM experts over the period of time, outlining ways to achieve portability and performance within your Revit families, during the process of its creation. Parametric components of the Autodesk Revit which are also called families provide an environment which facilitates users in design making and by giving a practical approach. Its features allow an ease in the changes and any change in any element will alter the whole model of the infrastructure accordingly and automatically. There can be various forms of a family such as a door, a window, a wall or a table; hence anything which is needed to be portrayed in the project can be a part of the family. The families that are included in Revit are predefined. In spite of availing various family options, users sometimes need to create their own customised parametric components which can be achieved with the help of the family editor that is available in the software. No programming language is needed to be learned, the creation of a family can be done through the template which is provided to initiate the families. The parameters remain unchanged once they are created and any edition can be done within the project. There is also an option for creating a nested family in the Revit family which simply means that n number of cofamilies can be created in the Revit family. Before creating a family, users need to review various considerations like the size of the family, different layouts of the family, the detail that will be needed to be integrated, the requirement of the origin point of the family and much more. Types of Revit Families: After the completion of the above queries, the user is all set to go ahead and create a family. Autodesk Revit contains three types of families which are detailed below: System Families: These families consist of the basic component of any infrastructure like the ceilings, walls, floors. By making amendments in the properties of the original version, the users can make their own duplicate ones. 2018 Revit Modeling India 2
In-place Families: The components that comprise these families are one of a kind and are not supposed to be reused in the further projects as their dimensions and properties differ from one project to another one. Standard Component Families: These are of a common type of families that are provided in the Autodesk Revit software. The one who has got experience in handling the software can create perfect and practical families which can range from the electrical to rendering using the parametric models like the dimensions and properties. The parameters control the families which define the geometry. For instance, how many materials in how much quantity, can be easily shaped by inserting the parameters in the software. Rendering tool allows users to make an authentic graphic of the model which in other cases may look like a pictorial one. The smooth functioning of the software enables the users to keep a track record of the 3D effect of the model by incorporating the 2D inputs in the form of raw data. Autodesk Revit is furnished with a unique feature that authorizes the users to make changes in any element which will result in the automatic alteration in the whole model accordingly. 2018 Revit Modeling India 3
Points to be considered before Revit Family Creation: While we create the Revit family the determined use of this family in the particular defined project environment helps in determining to what extent it is designed. You are allowed to develop and design the families in order to include numerous representations which can be used in different project phases and project views. The Uses of the Family: Before one initiates the creation of the Family it is important to consider a few of the primary questions like: In the particular family defined on specified manufacturer s content or is it a generic family? What are parameters which the family would need? Which template should be used? What are the real purpose and intent behind creating a family? What is the level of detailing required? If we add certain unnecessary parameters then there are chances of increased size of model and decreased level of performance. Level of Detail: The level of details helps in determining which of the piece of the family geometry shows different kind of views to the project. When you create a Revit element and add it to the view of the project then this current level of view helps in displaying the appropriate and complete family geometry. While you decide what are required level of details to be displayed, you may use these recommendations: Do not design the geometry which isn t visible after the family is inserted into the building model. 2018 Revit Modeling India 4
Like, in case of table family which is inclusive of the drawer you need to just present the face of the drawer and not the whole of it with its content. Try not to duplicate geometry which may be put to use at other level of details. Element Visibility: To be specific, the geometry defined for each element which had been created by family will keep on changing based on the present view of the project. The setting in regards to visibility of the family helps in determining that which of the project view elements designed using family shall be on the display. Nesting Families: A nested family is known to be the one which are loaded in other family. In few of the cases it is quite easy to present the few of the parts of the nested family differently from the main model of the family. Recommendation for the nesting family: In place of nesting try to create all the important geometry in family. Try to utilise reference labels and lines in order to lock the geometry at its place. Try limiting nesting to just two levels: The depth to which the family is nested defines the longevity of the time while updating the project file. Try to nest only content having high value and which can be used in case of numerous different families like door handles. Take precautions while you change in nesting component which has been shared by more than a family. While you will reload the components it will help in updating all the other families in file who shares same nested families. You can control the step by removing the tick on the shared button which is displayed in category and parameter dialogues. Make sure that maximum six nested families are nested in one family. Category 5 32 200, Sub category 80 Category 65 40 200, Sub category 90L 2018 Revit Modeling India 5
Family Size: It has been seen that number of large Revit families can have major impact on the performance related to BIM. So it is suggested to audit and purge the families before finally uploading them, also try keeping nesting to minimum, and also make sure all the nested objects have been audited and purged. Make sure a limited amount of bitmaps and custom materials are utilised. Try and model which is necessary to defined level of details. Avoid the usage of any CAD or images when you are building the component and make sure you never explore CAD into the family. 8 Steps for Creating Revit families: The procedure for creating a Revit family can be very easily explained in the following below points: 1. Choice of the Best Family Template: It defines the type of family that the user wants to create in Revit environment which depends on the category that the user wants to choose with reference to the parameters. 2018 Revit Modeling India 6
2. General Layout of the Family: Different families have different parameters depending on the requirement and the templates are selected accordingly. 3. While working on the software, users have to be cautious regarding the correct view, elevation, and floor. If the reference view is modelled in a plane view, it can be viewed in the related elevation view. After doing this, the origin of the family is decided. By integrating these two planes, other reference planes will be created through which the control structure of the family will be decided. 4. Creation and Association of Parameters: By creating parameters the users will get the estimate of the family but the parameters should not be complex. There are different ways of relating the parameter to the main element of the family. 5. Extrusions, blends, revolves, sweep, swept blend and equivalent void forms are the tools that are offered by Revit for geometry generation. These tools can be applied only when the reference plane is selected. 6. Checking the Family: For testing the accuracy of the parameter, whether they are working right or not, the value of the parameter should be changed in order to see if the value so filled is adapted automatically. 7. Formulas and Arrays: It is one of the powerful aspects which is used to control the families in various ways. Linear and circular arrays are possible due to the Revit array tool. 8. Saving the Family: When all the important and possible additions are done in the Revit family, it is ready to be operated, it will be saved with a suitable name and in an easy to find location. 2018 Revit Modeling India 7
Best Practices to Use While Creating Revit Families: Stay Minimal: It is suggested to have the detailed levels for elevations and plan representation and also have certain display options available on visibility settings. Bring to use the symbolic lines and also masking regions in place of geometry. Also try to stay minimal while you model geometry with the help of the defined visibility settings. Do Not Over Model: While creating assemblies make sure you have limited the creation of assemblies and parts in order to avoid the overloading of the model with all kinds of unneeded details. Make sure you only consider the important assemblies. Limit Usage of Nested, Detailed and Parameterized Families: It is important to understand the importance of parameters in terms of Revit families. With the correct usage of parameters and nested families there are huge chances of success while customising and building the families. But it is important that the usage of nested and parameterized families is only to the point it is necessary, as any overloading can lead to complexity which may make the product limiting and frustrating. Use Families in Place of Group: To a fact families are considered to be lighter than groups. Thus, it is suggested to use families in place of groups as much as possible. 2018 Revit Modeling India 8
Another reason of considering families over group is that even though groups are much powerful than families but it takes time to update all groups at instance which affects the efficiency of the project and design. Avoid Over-usage of Voids: Voids can be considered to be of great use when they are utilised sparingly but they may impose penalties in terms of performance if they are used improperly or are overused. Many a time voids present the only way to model the elements accurately. However, it is suggested if possible try building the elements using solids instead of voids. Avoid Formula and Array: The extensive usage of Formula and Arrays can add to the overall size of the families and thus it may affect their performance at the project level. Also if arrays are used sparingly in one family and the family is copied numerous times in the project the performance will still be impacted. Use Masking Regions and Symbolic Lines: In order to reduce the model size and keep a check on the complexity of the project it is suggested to use masking regions and symbolic lines in place of complex 3D geometry. It helps in giving a detailed show and that to with more than one view like 3D views and elevation and still reduce the complexity of the project and its size as well. All Families Need Not be Parametric: It is important to plan parametric relations and then create the family skeleton which is able to feature the major parametric relations. But it is important to ensure that you build only that parametric family behaviour which is required to avoid over-hampering of the model. Thus, all families are not required to be parametric. Use Family Component Rather Than In-place Families: In case the components are required to be used repeatedly it is important to make sure that you create family component in place of using in-place families. While you copy any in-place families a completely new entity is generated every time in place of just referencing the information available from the initial instance. This increase the workload and complexity of the project. 2018 Revit Modeling India 9
Revit Families Enhance Revit performance: Never Explode CAD Drawing into the Families: In Revit it is suggested never to explode any AutoCAD file. Even when they are deleted every XREF will be treated like an imported symbol which will only add data to the file and also reduce the performance of the project. If you wish to explode any file make sure you purge XREFs first and also make sure you use the purge unused in Revit in order to avoid extraneous files. Try to utilise CASEs like import from File tool in order to import it to the separate Revit file and also make sure you remove?rogue?rogue? style of lines with the help of program s tool known as change and replace linestyle in order to purge the families and then you can finally load this into the active project. Eliminating the Unused Families: It sounds more like any mafia act. Revit families that are no more the part of the model may still be contributing to the size of the file. To order to increase the performance purge use the families often as it makes it easier to remember which one shall go with the defined situation. Also make 2018 Revit Modeling India 10
sure you remove only the families without touching the types as it may be hard to introduce them again once they had been erased. Try Avoiding Extreme 3D Model Detail: In case of Revit family if it becomes too detailed there can be an impact on the model display performance especially in terms of large projects. In case highly defined models are needed try creating low and high detail version of required families. Try using the family type parameters while you switch between such versions based on the type of output required. The low detail version is expected to be quite simple (only a bounding box which depicts size and shape) with the visibility parameter staying turned off, whereas, the high detail version are allowed to be switched off temporarily for the purpose of exporting and visualization. 2018 Revit Modeling India 11
Author: Premal Kayasth a BIM Evangelist who earned a Diploma in electrical engineering from Polytechnic Engineering College - Ahmedabad, Gujarat. Premal holds an overall experience of 12 years within the construction industry and from last 8 years he is explicitly involved on BIM projects with renowned names in industry. References: 1. https://knowledge.autodesk.com/support/revit-products/troubleshooting/caas/ sfdcarticles/sfdcarticles/best-practices-for-families-modeling.html 2. https://revitmep.blogspot.in/2007/07/best-practices-for-autodesk-revit.html 3. https://redstack.com.au/revit-modeling-best-practices.aspx 4. https://storage.googleapis.com/bimstore-uploads/uk/uploads/software/bimstorebible-v14-published.pdf 5. https://knowledge.autodesk.com/support/revit-products/learn-explore/caas/ CloudHelp/cloudhelp/2018/ENU/Revit-DocumentPresent/files/GUID-31DECCD6-54B4-408D-A579-3E67A1F59E6E-htm.html 6. Image courtesy: http://bimobject.com/en/product 2018 Revit Modeling India 12
About Revit Modeling India: Revit Modeling India (RMI) is a BIM technology specialist for AEC and Design/ build industry. With years of practice and experience in Building information modelling, RMI offers BIM related solutions covering 3D BIM modelling, Clash detection, 4D scheduling and simulation up to 5D cost estimation services and Facilities Management. We are extensively using Revit as a BIM process supporting application and are profound with all methodologies and functionalities of Revit as a BIM tool. Our consultative approach and customer first attitude has earned the company accolades from its customers and an impressive rate of customer retention. We have a strong team of 30+ BIM technology experts, who accompany great exposure in serving different industries on various projects such as Residential, Commercial, Educational, Healthcare, Hospitality, Workplaces and Retail. To learn more on our BIM solutions or for any question related to this white paper, write to our BIM Experts on info@revitmodelingindia.com. 2018 Revit Modeling India 13