Create a Hatched Clearance for Revit Families

Create a Hatched Clearance for Revit Families
A friend came to me today with an interesting Revit task: She needed to show the ADA
clearance on a refrigerator, but needed to be able to have it visible in one view, while
suppressed in others. Additionally, she wanted to show the clearance areas with a hatch pattern
in plan view.
There are a few steps to getting this right.
1. I created a clearance family, that nests into the
host family (so I can use it over in other
2. You need to make a new subcategory
3. You need to make a new material
4. You don’t NEED to make a new fill pattern, but
I recommend it (for more control)
If you don’t use a new fill pattern, this would be the
scale of your hatch lines, should you plot at ⅛”=1’0”
Create the Clearance Area Family:
Start a new family, using the “Generic Model” family
template. Create a set of reference planes with dimensions
as illustrated.
Elevation View
Assign the 3 dimensions to labels
(Instance type parameters)
Create an extrusion object, and lock it to your
reference planes
Our next task is to assign
“Labels” to our dimensions. This
allows us to control the
geometry in the family by
properties dialog.
To assign a dimension to a
label, select the dimension ==>
pull down the label control on
the toolbar, and select <add
new parameter>. Do this for length, width and height.
Make sure you select instance parameter type for each one!
THIS IS VERY IMPORTANT!!! - Since we started with
a generic model template, we have not assigned a
category to this object. we must assign the category,
before we assign a sub-category - or else your sub
category will be in the wrong place!
So - which category? - Since this is being designed as a
nested reference, we need to match the category on
this guy, with the category of the family we’re going to
put it into. Huh??
We’re putting this into a Refrigerator - which was
designated by my Architect friend as “Specialty
Equipment”. So - we change the category in this family,
to also be “Specialty Equipment”.
Finally - In order to accommodate our needs, we must
be able to control the visibility of this object from one
view to another, independent of other objects that will be in this family. This is where
subcategories come in. We are going to create a subcategory of “Specialty Equipment”, called
ADA clearance, then assign or extrusion to that category.
Press the object styles button on your ribbon interface, then create the new subcategory.
Go back to your model, select your extrusion. In the properties pallete, go to subcategories
parameter, pull down and assign your newly created ADAClearance to the object. You should
see your color change on your extrusion object.
Halfway home! - Create a new material
Now you have your control that will be used in your project’s visibilty graphics to isolate this
component. What we don’t have, is a nice hatch pattern for our ADA plan view.
Typically if you hear the word “Hatch Pattern” in Revit, you think detail component family. But,
that won’t work in this case, as detail components cannot be assigned to subcategories inside
families. (Autodesk - are you listening??! wish list item, perhaps?)
Instead, we’re going to assign a material to our extrusion, and use the surface/cut patterns in
the material definition to show a nice hatch in our plan view. (It’s easier than it sounds).
Go to Manage Tab ==> Materials Button. I duplicated the “Glass” material, Called it
ADAClearance, and applied the following properties (at first)...
Now, you have to assign this material to the extrusion object as well. (similar to assigning the
Go to your model, pick the extrusion, and assign the newly created material to the object.
NOTE: I have not been intermittently testing this family as I build it (which is unusual when
building parametric families, you should frequently test, or “FLEX”, your family in a project). The
reason is, when I load this family into a project, it’s going to load my custom material,
subcategory and as I am about to show, custom fill pattern. If that happens, and you change
any of those items, you have to transfer project standards from the family to the project, or
modify them manually, in all locations ... in short, it can get a little tricky.
Until now, I have been designing my
family with the scaling factor ½” - 1’0”. However, most of the time, plans
are drawn at ⅛” scale. When I change
the scale for the view, I see the
impact it has on my hatch pattern.
The lines aren’t wide enough for my
liking using the default diagonal up fill
To fix this, we will create our own fill
pattern, with a tighter line spacing.
To create a new fill pattern,
Create a new (drafting
type) fill pattern.
For the fill pattern, I used the default, named it
“ADAClearance” and changed the spacing to 1/16”. That’s it.
Finally, go back and Re-Assign your materials surface and cut patterns (see above if you need
a refresher) to use the new ADAClearance style.
Save your ClearanceArea Family.
Nesting your clearance family to the refrigerator family
Since we already have our clearance family
open, all you need to do is open the refrigerator
family. go back to the ClearanceArea family, and
press the “load into project” button, if you only
have one other project open, it will load
automatically. If you have more than one, you’ll
get a dialog like this. Obviously, we want to load
to our refrigerator project
Once the ClearanceArea family is loaded,
place an instance of it in your plan view of
your refrigerator family. Align and lock the
family to the reference planes shown.
Next, you need to “Map” your parameters from the ClearanceArea family to parameters in your
host family. (Refrigerator.rfa). Start by selecting your Clearance Area Family. You will see your
Clearance Parameters you made earlier (as long as you made them instance parameters!) in
the properties palette. There’s a tiny button next to them - which is what you will push to assign,
or “MAP” those parameters to new parameters in the current host family.
A picture is worth a thousand words... so here ya go...
I like to assign my adjustable parameters to the constraints category, so the appear at the top of
the properties list for end users. Keeps them from having to hunt for them - or change
parameters they shouldn’t!
Repeat this for all three parameters. When finished, your family types dialog should look like
I also assigned the ADAClearanceHeight to be equal to whatever the height was for the
refrigerator type.
Load to a project, and test.
3D Clearance (works with clash
Floor plan with ADA clearance override off
Floor Plan Showing ADAClearance
Using the visibilty graphic override to change visibility on different views of the same project.