BIM families are the building blocks of any Revit project. Well-crafted families can dramatically improve project efficiency, while poorly made families can cause performance issues, coordination problems, and endless frustration. This comprehensive guide covers everything you need to know to create professional, high-quality BIM families.
Family Planning and Structure
Before you start modeling, proper planning is essential. Consider the family's purpose, how it will be used, and what variations are needed. A well-planned family structure makes the modeling process smoother and results in a more flexible, reusable component.
Key Planning Questions
- • What is the family's primary function?
- • What parameters need to be variable?
- • Will it be hosted or stand-alone?
- • What level of detail is required?
- • How will it be scheduled?
Parameter Strategy
Parameters are what make families flexible and powerful. Use shared parameters for values that need to appear in schedules. Create instance parameters for values that vary per placement, and type parameters for values that define family types.
Best practices for parameters:
- Use consistent naming conventions across all families
- Group related parameters logically
- Add formulas to automate calculations where possible
- Include material parameters for proper rendering and scheduling
Geometry Best Practices
The geometry you create should be clean, efficient, and appropriate for the view scale. Use symbolic lines for 2D representations in plan views, and model geometry only where necessary. This approach keeps families lightweight and improves project performance.
Level of Detail
Create appropriate geometry for Coarse, Medium, and Fine detail levels. Use visibility settings to control what appears at each level.
Symbolic Lines
Use symbolic lines for plan representations. They're much lighter than 3D geometry and provide better control over appearance.
Nested Families
Break complex families into nested components. This improves flexibility and makes updates easier.
Performance Optimization
Performance is critical, especially in large projects. Optimize your families by:
- Minimizing the number of faces and edges in geometry
- Using simple extrusions instead of complex blends where possible
- Avoiding unnecessary detail that won't be visible at typical view scales
- Testing family performance in a project environment before deployment
Quality Control Checklist
Before deploying a family, verify:
- All parameters are properly named and organized
- Geometry appears correctly at all detail levels
- Materials are assigned and render correctly
- Family works in all required host types (if hosted)
- Schedules include all necessary parameters
Conclusion
Creating high-quality BIM families is both an art and a science. It requires understanding Revit's capabilities, planning ahead, and attention to detail. Well-crafted families become valuable assets that improve project efficiency and quality. Invest time in learning these principles, and your families will serve you well across countless projects.