Controlling the level of detail of elements in Revit: the rose windows of Notre Dame

Blog-Article-Alfredo-Medina-Revit-Notre-Dame-SubcategoriesRevit offers several methods for controlling level of detail, but, do these methods work if you want to control the appearance of a single element? Let’s do a quick review of these methods.

Using the Level of Detail Icon?

If you use Revit, you should be familiar with this “Level of Detail” option in the view control bar:3 options: Coarse, Medium, and Fine.

Level of Detail icon

Once an option is selected, the setting is applied to the entire view. Revit looks for visibility settings in each family to determine how to display each element. This is fine, but, what if you don’t want to do a change that applies to the entire view, but only one or certain elements?

Using Level of Detail by Category?

Another alternative is to use the Visibility Graphics window, find the Detail Level column, and assign a detail level (same Coarse, Medium, Fine) to a category. This is fine, but, what if you don’t want to assign a detail level to all the elements of a category?

Levels-of-Detail-by-category.png

Using Override Graphics by Element?

Maybe selecting the element, right click, Override graphics by Element? This dialog box shows many choices, but there is no way here to apply a detail level an element.

Override Graphics by Element

Using Visibility Parameters in Families?

If you create visibility (Yes/No) parameters in families, and associate parameters to elements, then in the project, can you show the family in one way in one view, and in a different way in another view, using the same type? Hmm… No. This works well to control the appearance of a family in one view, but once you select your choices for visibility parameters, the element will be presented in the same way in all the views. And if you change the type in the family to change the appearance, now the family will use that type everywhere.

Using Subcategories?

We’re running out of choices. Well, let’s see, using Subcategories we can control the appearance of elements, not entire views, nor categories.. With subcategories, one family can be presented in different ways in different views, without changing the type of family and without using visibility parameters.

I typically don’t use Subcategories, but I have found 2 cases in which Subcategories was the only solution or at least a good solution. The first case was when I made a set of families for residential elevators. The same family had to be shown differently on first floor and second floor. The only way to accomplish this was to create a subcategory for “lower floor”, another one for “upper floor”, and then set certain elements in the family to their correspondent subcategory. This solved the issue of presenting the elevator properly in both floors.

The second case is in the modelling of the rose windows for the Revit model of the Notre Dame cathedral, an initiative started by Andrew Milburn, in which I am happily collaborating. These are no ordinary windows. They are as tall as a 4-story building, a square of 12.90 meters side. That’s approximately 42 feet wide and tall. Very rich in detail on the exterior, and even more impressive in the interior where light creates a dramatic effect on the little colorful shapes of stained glass.

Why are Subcategories not popular? Maybe because they “can get messy”, as Paul Aubin said in our Slack chat group this week. It is true. It can be annoying to find a list of subcategories in our projects if we don’t know what they are for or how we are supposed to use them. However, I think, in this case of remote collaboration, we can agree on the usage and the names of these subcategories, so that it is not strange for any of us. So, instead of being an annoyance, this can be an useful feature to handle the level of graphical details in several elements in this model. This is not a typical project. Not everyday we work on the model of a Gothic cathedral. Therefore, if the system of “Coarse, Medium, Fine” is not enough in this case, and if there is another tool that solves a problem, let’s use it.

The rose windows need to show a simple geometry in the overall elevations at scale 1:250. And, more detail as necessary in partial elevations at 1:50. And, even more in enlarged views or details. On top of that, the highest level of detail is necessary for the interior renderings. Therefore, to solve all these requirements, I have created these 5 Subcategories:

Levels of Detail subcategories

 

 

 

 

The rose windows are of the Window category. But the small parts are nested generic model families. Therefore these subcategories apply to generic models, not windows. Using the same format, other families for other purposes, could control the visibility of their components with these same method and subcategories.

In the rose window families I have set elements to their correspondent Subcategories, like this:

Level of Detail 1

In addition to the main square and circle, this level of details shows the basic geometry of the windows. This is just fine for the overall elevations of the cathedral. More detail beyond this point will make the windows less legible. Therefore, for the overall elevation, only the Detail Level 1 is on.

South Rose Window                                                                            North Rose Window

Notre-Dame-Rose-Windows-Level of Detail 1, NerdyAlf blog, Alfredo Medina

Level of Detail 2

In this view, only Level of Detail 1 and 2 are on. We see now other figures, like that shape made of 3 arcs that goes in between each “petal” of the rose.  There are 12 of those shapes for the South window, and 16 in the North window. Also, we see now that other figure with 6 arcs, at each corner.

Notre-Dame-Rose-Windows-Level of Detail 2, NerdyAlf blog, Alfredo Medina

Level of Detail 3

In this view, only Level of Detail 1, 2 and 3 are on. We see now other figures in the perimeter, and in the corners. Also, the ring at the center.Notre-Dame-Rose-Windows-Level of Detail 3, NerdyAlf blog, Alfredo Medina

Level of Detail 4

In this view, Level of Detail 1, 2, 3, and 4 are on. We see now all the geometry, including all the black rings that are visible only at close distance. These would be good for  an enlarged detailed view of the window.

Notre-Dame-Rose-Windows-Level of Detail 4, NerdyAlf blog, Alfredo Medina

Level of Detail 5

Here, all the 5 levels of details are on. In addition to all the figures, now we have a divided surface, which represents the stained glass.

Notre-Dame-Rose-Windows-Level of Detail 5, NerdyAlf blog, Alfredo Medina

Level of Detail 5, in shaded mode

Here, all the 5 levels of details are on. In addition to all the figures and the divided surface, we have added a shaded mode to see the materials and the random colors of the stained glass.

Notre-Dame-Rose-Windows-Level of Detail 5 in shaded mode,

With the passing of light, the negative shapes of the geometry take precedence in the interior.

Notre-Dame-Rose-North-South-Window-Level-of-Detail-5-plus-render

 

In the overall elevation, despite of its size, the rose window is just another element, represented in the lowest level of detail, level 1:

Notre-Dame-Overall-South-Elevation.png

For this image, a rich texture is desired, therefore the level of detail of the window is raised to 4:

Notre-Dame-Rose-North-with-context

 

For interior renderings the Level of Detail 5 is needed to see the stained glass and all the geometry. This is the South Rose Window:

Notre-Dame-Rose-South-Window-Level-of-Detail-5-plus-render.

 

And this is the North Rose Window from the inside:

 

In conclusion, the addition of subcategories in this particular case, has given us control over the appearance of the rose windows in different views for different purposes. The same 5 subcategories (not necessarily all of them) could be used for controlling other elements of the same model.

Stay tuned for more blogs about these topics, and more stories about the Notre Dame model.

Alfredo Medina

 

1 Comment

  1. Alberto Luiz Lisbôa de Azevedo on July 10, 2019 at 11:53 pm

    🙂

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