Article

# Parametric Modeling of Vaults for Notre Dame in Revit – Part 4 of 6

## Part 4: Adding Parameters, Placing Vaults on Columns, and Modeling Ribs

At the end of Part 3, our 1 x 1 prototype of a four-part vault looked like this:

Here in Part 4, it's time to make the vault grow because we need to model ribs and arches with their actual size. If we inserted the vault now into a project, and put a person next to it, this is what we would see. Not very impressive yet.

There are different ways to control the size of the vault (or any family in the adaptive template).

### Method 1: Reference Planes, Dimensions and Parameters

In plan view, align and lock reference points to reference planes, in both directions x and y. Create dimensions to control the distance between reference planes, and convert dimensions into parameters for Width and Depth. The heights are already controlled by the nested families that we created before.

This is a six-part series. Click the links below to continue working.
Part 1
Part 2
Part 3
Part 4
Part 5
Part 6

### Method 2: Hosted Reference Points with Offsets

This has to be planned from the beginning. After creating reference point A, host a point B on a vertical plane of point A (the plane that is aligned with line A-D); then associate the Offset parameter of point B to a parameter for Depth. Then host a point D on a vertical plane of point A (the plane that is aligned to line A-B); then associate the Offset parameter of point D to a parameter for Width. Then host a point C on a vertical plane of point D (the plane that is aligned to line A-D); then associate the Offset parameter of point D to a parameter for Depth. This method does not use dimensions nor reference planes, only points.

### Method 3: Shape Handle Points

Select reference points A, B, C, D, and change their "Point" property to "Shape Handle Point (Adaptive)."

If you use this method, the vault will be inserted in the project at the same size it was modeled in the family, and if you need to change its size you need to move all four points to the desired dimension.

### Method 4: Adaptive Points

Select reference points A, B, C, D, and change their "Point" property to "Placement Point (Adaptive)."

If you use this method, the vault will be created only after you finish clicking points A, B, C, D, in the proper sequence, in a project or in another family. It's like executing a program by steps, 1, 2, 3, 4, done.

### Which Method Should We Use?

Method 1 is the same method we use in generic families. It is simple and practical for adaptive families that are simple, co-planar, like the host family of this square vault. For more complex families, I prefer Method 2. Method 3 is user friendly in the project, but it might be slow. Method 4 is necessary only if you need to adapt a family to multiple shapes and varying conditions, such as the vaults at the semicircular array in Notre Dame. You should choose the method that works better in each case. If you use Method 4 for a family that could be done easily with Method 1, probably you will end up complicating things.

To control the width and depth of the vault, I am going to use Method 1. The heights are already controlled by the nested families using Method 4, based on the distance between two points. Therefore, to control width and depth, I do this:

Now, in the project, our vault has its actual width, depth, and height, and we start getting a sense of its scale. Assuming that the vault is still on the floor, not on columns yet, it would be like this:

But only when we add the vertical dimension, that impressive vertical dimension of Gothic cathedrals, putting the vault on top of columns, 6.8 meters tall (approx. 22' 4"), the same vault creates now a totally different effect.

If that module of a vault on top of four columns is repeated over and over, we start feeling that effect of grandiosity. Look at the size of our man now in relation to the space created by just repeating columns and vaults:

Now that we have the actual size of the vault, let's model the ribs. That is what the builders had to build first, the ribs. Well, after the wooden scaffolding for the ribs was ready.

What was the profile of stones used for the ribs? According to some illustrations in Viollet Le-Duc's dictionary of French Architecture, the profile is something like this, below (the purple area represents the stone blocks of the vault in section).

What are the dimensions of the profile? I don't know exactly. Using Leica's panoramic images and measuring tools, when I measured that profile, I always obtain something similar to one foot wide, give or take. You can try this by yourself.

Therefore, I am going to assume that the profile is one foot wide, like this:

Other illustrations in Viollet Le-Duc's dictionary suggest that the profile has a central deeper section; something like this:

When I say "profile", speaking of a profile to be used in an adaptive family, I am referring to a generic model family, work-plane based, not always vertical, that contains a flat closed shape made with model lines.

To use my profile, I load the profile family into the vault family, then use reference > point, click on "Draw on face" (1), then put the point on the diagonal of the semicircular arc, then use the Set tool (2) and select a plane of that point as the current work plane (the plane that is perpendicular to the semicircular arc), and then place the profile family on that point, using the Tab key until the profile is oriented properly (highlighted below). Then select the profile family and set its Visible property to be off.

Then, select both the diagonal and the profile, and do Create Form. Now you should have one rib. Repeat the process for the other diagonal. Now you should have two ribs, like this:

If we turn on the surfaces and load the family again into a sample project, now we see the ribs, as shown below. And we realize that the top of the capitals needs to be bigger, to accommodate these ribs and the upcoming arches. The diameter at the top of the capital is now approx. 90 centimeters in diameter (some 3'), which is more or less what the Leica's panoramic images show. (These columns are just place holders and will be replaced later).

This is a six-part series. Click the links below to continue working.
Part 1
Part 2
Part 3
Part 4
Part 5
Part 6

Alfredo Medina is a very experienced and knowledgeable BIM / Revit professional with a background in architecture, high skills in training, troubleshooting, technical support, parametric modeling, extraction of quantities, definition of standards and best practices, clash detection, and coordination of large BIM projects. Alfredo has several years of experience and a reputation as an expert due to his participation in forums and international conferences.