Join Paul F. Aubin for an in-depth discussion in this video Using reference planes, parameters, and constraints, part of Revit 2018: Essential Training for Architecture (Imperial).
- [Instructor] In this movie we're going to look at reference planes, constraints, and parameters. Now reference planes are how you add structure to your families, and constraints and parameters are how you add smarts. So I'm in my file, and I've got four windows tiled, and you don't have to keep all four windows tiled but I think it's a pretty good idea. And I'm working here in the Floor Plan: Ref. Level initially. Now there are two reference planes already in this file. So if I select this one right here, you'll see it's named Center FrontBack and it's pinned, and then I'll select this one and it's named Center LeftRight and it's also pinned.
And the reason that those two are pinned is because they represent the insertion point of this family. So what I want to do is add additional reference planes to find the size of my pool table and I want to make sure that that size always stays centered on this insertion point. So to do that, I'm going to go to my Create tab here, and on the Datum panel I'm gonna click the Reference Plane button. The shortcut is RP, and make sure that you're choosing Reference Plane and not Reference Line, because there is a big difference between those two.
Now I'm going to start just above the horizontal reference plane and drag to the left and click a second point. A dimension will appear, and I'm just going to make that a nice round number of two. Press enter. Then I'm going to create another one that starts over here, click a point and click straight down, making that one go vertically and I'll set that to four, and then I'll click the Modify tool to cancel out. Now I'm going to fine tune the lengths of these just slightly here, because I want them to overlap one another just a little bit.
Then I'm going to take this reference plane and mirror it around the center, and this other one and mirror it around the center, and then let's just pan slightly to clean up the window, and let me just adjust the lengths of these slightly. So I now have these four new reference planes, which mark the overall size of my pool table. So at the moment, if you were to grab one of these and move them, they would move completely freely anywhere you want. So I'm going to undo that. Now, you may recall that the reference planes that we started with had names, but the ones that we've created, they don't currently have names yet.
Well, notice that there's this small Click to name control handle on the reference plane. Well, if you click right on there, you can give this a name. So I'm just going to call this right edge. I'll call this left edge. Front edge. And back edge. And it's a pretty good idea to get in the habit of naming your reference planes. It helps you keep everything all straight. Now the next step is to control their behavior.
You saw that I was able to move it freely. I want to add some dimensions. So I'm going to use my Aligned Dimension tool, DI is the shortcut, and I'm going to add a dimension that goes from my left edge to the center to the right edge. I'll place that up here, remember to click an empty space. Then I'll go from left to right only, skipping the center. Place that one above. And I'll repeat in this direction. Like so. Cancel out of the command. Zoom in a little bit, but the numbers are still a little bit hard to read, so you can actually change the scale of this view.
And I'll make it quarter inch, and now when I zoom in I can actually read what's going on here. The lower dimension that's four feet four feet, I wanna select that and toggle on the equality. And I'll do the same thing with this one. Two feet two feet and toggle on the equality. That's a kind of constraint. So what's happening now is if you tried to drag this reference plane it would move the other one an equal and opposite amount. So I'm going to undo that. The other dimension, the two long dimensions, I want to turn those into labeled dimensions that are assigned to parameters.
So I'm selecting the eight foot dimension, and up on the ribbon, you're gonna see a Label Dimension panel. There's a drop down here, but I currently don't have any parameters to assign. So right next to that I have a Create Parameter icon. I'll click that, let's move this out of the way, just so that it doesn't cover up the window, and let's give this a name. Now, it's gonna be a Type parameter, as opposed to an Instance parameter. A type parameter means, like we've seen in many other examples, that if you change this value it will update all instances of this type.
Pool tables come in certain lengths, so a type parameter seems like an appropriate way to assign this value, so I'm going to leave that. I'm going to accept the defaults here of length and dimensions, but down here under Edit Tooltip, if you want you can actually select all of this text and delete it, and you can input something a little bit more descriptive. Now this is going to be useful for your end user, just in case they're not sure exactly what to type in here. Now I'm going to select all of that text, do Ctrl + C to copy it to my clipboard, I'll okay twice here, select the four foot dimension, create another new parameter for it, call it width, leave it a type parameter, edit the Tooltip, select all the text, and do Ctrl + V.
And now all I have to do is change this part of the Tooltip, and click okay, and then okay again. So what has that done for us? Well, we've now created two labeled dimensions that are setting the overall width and length of this pool table. On the Modify tab on the Properties panel, there's a Family Types button. We want to click that next, and that takes us to the Family Types window. Here's where we do a variety of things in our family, but one of the things that we're going to do here is flex the family.
Now, flex is the word that Revit uses for testing. So once we've created parameters that are adjustable, we want to adjust those parameters and make sure that they're working properly. So all we have to do is come in here and try some other value. So I'm going to put in nine here and click apply, and the object flexes. I'll set it back to eight, click apply. I'll try three here, click apply. The object flexes, that's great. Let's set it back to four, and click apply.
So as long as everything flexes and adjusts the way you want, then congratulations, you've created your first parametric family. Now granted, there's still plenty more for us to do, and there's a few more things I want to do in this Family Types dialogue before we close out of it. The first thing is, at the very top of the window it says Type name and there's nothing there yet. So the reason this is called Family Types is we can actually create the types for our family right here in this dialogue. So remember that every object in Revit has a category, furniture in this case, a family, pool table V1 in this case, and a type.
But we don't have any types yet. So we can use this small little icon right here to create a new type, and pool tables come in some standard sizes. So for this first size, I'm going to call it eight foot, and I'm going to click okay. Now, an eight foot pool table is actually 88 inches long, so I'm going to put in the inch symbol so that Revit knows I meant inches there, otherwise it's gonna be 88 feet, and then it's 44 inches wide, and again, don't forget the inch symbol, otherwise it's going to see that as feet.
Now I'm going to click apply, and you'll see it adjust slightly. So even though it's a eight foot pool table, it's actually seven foot four. Now let me click new again and create a seven foot pool table. So this is a little bit smaller size. Now, maybe I'm pulling these sizes off a cut sheet, and the cut sheet actually lists the width first and then the length next. So to keep myself from getting confused and putting the wrong number in the wrong order, I can actually select my width parameter here, and using the move up move down icons here, I can move it up, so that these values are in the same order that they appear on the cut sheet.
I think that makes a certain amount of sense. So the seven foot should be 39 inches wide, and the length should be 78 inches wide. Now to test out that new size, you just click apply again, and you'll see the size change. But more importantly, now we have the two sizes here on the list, so all I have to do is switch back to the original size, click apply, and it's much easier to flex my family now. So that's one of the huge benefits of going into Family Types early and creating a few sizes. Now, do you recall when we added the parameters, we gave them Tooltips? If you hover over the name of the parameter, it'll tell you the name, but then below that it'll show the text of that little Tooltip that you put in.
So that's where you'll see that further description if it's necessary. So let me go ahead and okay out of the Family Types dialogue, and as you can see the reference planes apply the overall structure to the family, but those reference planes are driven by a collection of dimensions. So you can apply constraints to those dimensions when you want to lock in the behavior, and you can apply parameters to those dimensions when you want to make the distance flexible. You use family types to flex those values, and that's how you create the framework for a parametric family.
First, get comfortable with the Revit environment, and learn to set up a project and add the grids, levels, and dimensions that will anchor your design. Then author Paul F. Aubin helps you dive into modeling: adding walls, doors, and windows; using joins and constraints; creating and mirroring groups; linking to external assets and DWG files; and modeling floors, roofs, and ceilings.
Paul also shows advanced techniques for modeling stairs and complex walls, adding rooms, and creating schedules. Finally, discover how to annotate your drawings so all the components are clearly understood, and learn how to output sheets to DWF, PDF, or AutoCAD.
- Understanding BIM and the Revit element hierarchy
- Navigating views
- Creating a new project from a template
- Adding walls, doors, and windows
- Adding plumbing fixtures and other components
- Linking AutoCAD DWG files
- Rotating and aligning Revit links
- Working with footprint and extrusion roofs
- Adding openings
- Adding railings and extensions to stairs
- Creating stacked and curtain walls
- Hiding and isolating objects
- Adding rooms
- Creating schedule views and tags
- Adding text and dimensions
- Creating new families
- Using reference planes, parameters, and constraints
- Plotting and creating a PDF