By Dennis Collin
Revit does have a few fill styles with its out of the box template files, but inevitably for certain disciplines there will be a need to add to this default list. Some grainy wood or perhaps some hexagonal hatch for some insulation. Complex fill patterns can be defined as a simple text file and are described as effectively a series of lines drawn at an angle and length which can then be applied as repeatable pattern.
The most complicated bit is in deriving the rules for the hatch pattern. It is important to remember that Revit has two different pattern types MODEL and DRAFTING, and they work in a completely different manner within Revit. Model patterns are defined at a fixed size and often used to represent elements like wall or floor tiles, e.g. Tiles in an octagonal, square arrangement. Whereas drafting fills resize with the drawing scale e.g. Concrete sectional fills in a wall or floor slab.
Some sample fill patterns or a pattern generator routine can be located from here:
The fill pattern text file needs to have the correct header for importing into Revit. With the correct indicator for Revit to determine if the definition a Model Hatch, or a Drafting Hatch type.
For Model fills the header should look something like this:
For Drafting fills the header should look something like this:
The header specifies the units used with the hatch type specified as Model or Drafting.
The numbers separated by commas relate to the angle drawn, origin, offsets and whether a line or a space should be drawn. It is sometimes useful to draw out the cell to repeat in AutoCAD or similar to visualise how the pat file is to be defined.
This simple text file should be renamed as a ‘.PAT’ file before importing into Revit. The next process is straightforward.
- Go to the Manage Tab>Additional Settings>Fill Patterns.
- Create a new Drafting or Model fill as appropriate.
- Give the new fill pattern a name and browse to your desired hatch file
The hatch pattern should appear in the preview and can now be applied to materials as desired.
If an error message displays upon import, then it is often an error in how the hatch pattern text file is defined, too few or too many commas or an incorrect header, but hopefully the pattern will import as desired.
In many instances users already have bespoke hatch patterns defined within AutoCAD. In a future post I will show how we can bring these many hatch patterns into Revit, without having to edit or convert AutoCAD ‘PAT’ files to the Revit standard.