Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member
In this movie, we are going to look at reference planes, parameters, and constraints. We're in a file called Pool Table V1, and this was created from the Furniture family template, and we're creating our own piece of custom family content here. If you've been following along and you want to continue in your own file, you can do that, or you can open the one I've provided here: Pool Table V1. Now I've got my four windows tiled onscreen and if you want to learn how I did that, you can look at the previous movie again. And I've got the Floor Plan: Reference Level active, and that's where I'm going to start.
Over here on the Create tab, on the Datum panel, we have a Reference Plane button. Now there's also Reference Line, so make sure you are choosing Reference Plane. The shortcut is R+P. And what I want to do here is lay out four reference planes in the plan view to kind of describe a rectangular shape. So the first one I'm going to do right about here, parallel, running horizontally. You'll see a dimension appear, and it's a somewhat random number, so what I usually like to do with that is click in that number and just make it some sort of a whole value.
So I'm going to go with 2 feet here. I am going to do a second one running vertically off to the side, and same thing; it gives me just sort of random number here, so I'm just going to make that a nice whole number like 4 feet. And then I'm going to cancel out of the command. You can draw the other two, if you want to, using the reference plane, but I usually find it faster to select it, go to Mirror, and mirror it around this axis, and then select this one and go to mirror, and mirror it around that axis. So it doesn't really matter if you draw them or mirror them, as long as you end up with four surrounding that center point.
Now the two reference planes that were here already were part of the template, and they mark the center point of the family. If you were to select them, you would see they also have a pushpin icon, and that prevents them from being accidentally moved. So if we are going to use those reference planes as the insertion point of our family, then it's kind of important that they don't move on us. Now the ones we just created are not push-pinned. Those can move freely. I'm going to undo that. What we're going to be doing is, using parameters and constraints, we're actually going to control the behavior of those movements.
We don't want them to be able to just move anywhere. Now, it all starts with dimensions. So these are the same dimensions we used in the project environment. Here is my Aligned Dimension tool, or we can do D+I. And I need a total of four dimensions here in my floor plan. I want one that goes from this left side to the center and continues to the right, and I'm going to put that up here somewhere, and I want to click the Equality Toggle for that. That's going to make those two maintain an equal-equal relationship.
Then I'm going to do a second one that goes just from left to right, bypasses the center, and I'll put that one above it. And I want to do the same thing in the other direction: top to middle, to bottom, pull it over here somewhere, make it equal, and then top to bottom, pull it over here. Now let me cancel out of the command. I'm going to use the Modify tool. It's a little tough to see what I've got here. So the scale down here is set it to half-inch. You can change that anything you want. It doesn't really affect the family in any way.
So I'm going to make it quarter inch equals a foot and zoom in a touch so that we can get a better look at what we've got. So we now have an equal-equal running both horizontally and vertically, and then we have a 4-foot and an 8-foot dimension. Now, with the equal-equal, that is a kind of constraint. So what I mean by that is if I were to select one of these outside reference planes and start to drag it, notice that the one on the opposite side will drag the equal and opposite amount. Notice that the overall dimension will change as well.
So let me undo that. Okay, so that's a constraint. The constraint in this case is saying, keep these reference planes centered, and we're doing that in both directions. What we want to be able to do is have this dimension and this dimension become what we call a parameter. I want my end user to be able to put in a numerical value there and have that adjust the size of the family, and here is how we do that. So I select the dimension and I go to the Label dropdown here on the options bar.
It currently says None. I'm going to choose Add parameter, and in this dialog here I'm going to name that Length. I'm going to accept all the defaults, click OK, and the word Length will appear in front of that dimension. That is now a labeled dimension, or another way to say that is, it's a parameter. Let's do it again for the 4 feet. I'm going to go to Label. I want to add a second parameter, call that Width, click OK, and so we now have Width and Length.
Now comes the part where we test it out. The Revit word for this is flexing the model, and that comes from the fact we're creating a flexible family, and so every so often we should flex it to make sure it's behaving properly. We do that with this button here on the ribbon. It's called Family Types. So we are going to click on that, and I'm going to move it out of the way slightly so that we can see the reference planes here in the floor plan and in the two Elevations, and the way you flex is to simply click in the Value field and try a different number.
So for example, I could put in 3 feet for the Width and 7 feet for the Length. When I come down here and click the Apply button, all of the reference planes should move and adjust. Now, what we are actually witnessing there is a combination of the parameter and the constraint. Because we've changed the length to 7 feet and we've said that it's got to stay equal-equal, it adjusted a little bit on both sides. So I'm going to reset this back to 8 feet by 4 feet, click Apply. Everything seems to be working.
Now there's a reason why this is called the Family Types dialog. You can actually speed up the flexing process a little bit by coming over here and clicking New, and what we're creating new is a family type. So if you remember when we get to our project environment, we'll have a family and then each family has one or more types. Those types are actually created right here in this dialog. And all the type is doing is flexing all the values for you. So another way to think of a type is, a type is just a saved and named variation of your family.
Now, because we're making a pool table, I'm going to call this first type 8 foot, and it's going to have a Width of 44 inches--and when I click out of that field, Revit will convert that to feet and inches, so if you want to type in 3' 8", you can do that too--by 88 inches, and I'm going to apply that. And you'll see it change ever so slightly. Then I'm going to click New again, call this one 7 Foot for a slightly smaller pool table, put in different values here, so I'm going to put in 39 inches by 78 inches, and again, it converts it to feet and inches for me, Apply.
Now if I want to flex between the two, I just open up the list here and go to 8 foot, click Apply, and it changes both values. Go back to 7 feet. It would change both values, OK. So that's the essential process of laying down the reference planes, applying some constraints, applying some parameters, and then the final step of flexing. We added the additional step of adding the family types just to make the flexing a little bit more convenient in the future. In the next movie, we'll begin taking this framework and building upon that to start creating the geometry for our family.
Get unlimited access to all courses for just $25/month.Become a member
100 Video lessons · 12033 Viewers
56 Video lessons · 11445 Viewers
83 Video lessons · 9354 Viewers
109 Video lessons · 5218 Viewers
Access exercise files from a button right under the course name.
Search within course videos and transcripts, and jump right to the results.
Remove icons showing you already watched videos if you want to start over.
Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.
Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.
Your file was successfully uploaded.