This is the continuation of an article that was published by Autodesk in September of 2016, as part of their Expert Elite Highlight series. It is recommended to read that article for a better understanding of this one. Please refer to this link: http://autode.sk/2cISh9r
Continuing my journey through the theme park, I find more elements that I can use to explain other things you can do with the adaptive template in Revit: Tilted Walls, Slanted Columns, and Adaptive Repetitions.
Tilted Walls
So I found this cute little “house”. This is basically four tilted walls, a roof, and some openings. Revit does not have a tool specially designed to create tilted walls, therefore, this process takes some steps.
First, you need to create a form. The form can be created in 3 different methods or places: with the mass template, with the generic model adaptive template, or in the project as a model in-place element. Since we are talking about the adaptive template in this article, we will use that option. After creating the form, you need to use the Wall by Face tool to create walls on the tilted faces of the form.
In the generic model adaptive template, reference level view, we will create two squares (or rectangles), A and B, as shown below. Square A is hosted on the reference level. Square B is hosted on a reference plane (indicated as RP in the image); this reference plane has been created at a height that represents the top of walls, and has been named such as “top of walls”. Square B is larger than square A, so that we can create four tilted surfaces after merging the two squares into a form.
Select the two squares and use the Create Form tool. In the image below, one of the slanted faces has been labeled as F. Notice the cube says “Front”, but, to work on that elevation, in the Project Browser you need to select the “Back” view. (Don’t ask me why).
Go to the Back view. Now you draw a triangle with reference lines. Where? On face F. To make the reference lines stay aligned to face F, click on the tool called “Draw on Face” (shown below). Then draw the triangle with reference lines. For this example, I drew the 3 lines without using 3d snapping, and I used a slope of 35 degrees.
Turn the view to the opposite side, and repeat the steps, to create another similar triangle on the opposite slanted, using the Front view. Then select the two triangles, and use the Create Form tool. That will create the “gable roof” volume. Then use Join Geometry to join the two forms.
This is all we need to do in the family editor. Now save this family and load it into a project. Once in the project, we will create walls, roof, and openings. Let’s create the walls first. In the image below, on the left, you see just the form. Then use Massing and Site > Wall by Face on each of the four slanted faces of the form. On the right, you can see the new tilted walls. I hid the form, for clarity of the illustration.
The roof can be done by Extrusion. We could do it by Roof by Face, but I think in this case, a simple roof by extrusion is good enough, and it will be easy to edit. To do that, in plan view, create a reference plane with a name, as shown with “RP” in the image below.
From the South elevation (indicated above as S) set the named reference plane as the current workset, and use the Roof by Extrusion tool, drawing a sketch similar to the image above. Using other views of the cube, you can adjust the depth of the extrusion. The next image shows the front and right views.
Finally, to create the openings, you can use a simple family such as “Opening-Door”, which is in the Openings folder of the library of families. If necessary, load that family, and create a type that is wide enough for this example. Then, from the plan view, just insert the opening in the tilted walls.
That completes the basic modeling of this little house with four tilted walls, a roof, and two openings. Remember, this is for a theme park, so you may want to add some fun colors to the house.
Slanted Architectural Columns
Continuing my journey through the theme park, I found this other intriguing façade. And I thought that this could help me to explain, in a practical example, some topics that I explained in concept in Part 1 of this article.
If you read that Part 1, you might remember that I wrote that in the adaptive template we can use points: Reference Points, Shape Handle Points, and/or Adaptive Points (also known as Placement Points). I also talked about profiles (work-plane generic model families with flat, closed shapes, made of model lines).
These slanted columns could be a good application of points and profiles. Let’s look again at the image, and look at the columns as linear elements between two points, with some profiles that create the forms. There might be other intermediate points to host the profiles of the different parts
I know that Revit has a tool to create slanted columns, but that tool is meant to be used for structural elements, and that is different; that is usually a simple extrusion. In this case we are interested in the architectural column, which has several parts.
Using the properties of reference points that I explained in Part 1 of this article, in the adaptive template, on the Back elevation view, I create the base point of the column. Then I set the rotation parameter of that point to a “Tilt Angle” parameter. Then, I set the horizontal plane of that point as the base for another reference point, which will be the top of the column. Then I connect these two points with a reference line, using “3d snapping”.
The offset for that second point from the first point will be calculated with trigonometry as the Hypotenuse of the triangle that the slanted line forms with the vertical reference plane and with the base of the roof. The column should be able to rotate to different values of the Tilt Angle, still maintaining its length constrained between the floor and the roof. In the image below, the Tilt Angle of the first point has been set to 10 degrees, which is estimated from looking at the picture. The Hypotenuse adjusts to the available vertical distance, which has been estimated as 10 feet.
Then, using the picture as a reference, I draw reference planes that help me to locate approximately the points along the axis of the column where there are changes in the form. Then I create reference points, hosted on the slanted line, at the intersection of that line with the horizontal reference planes.
These points will get a numeric value, in a parameter called “Normalized Curved Parameter”. That number refers to the position of each point along the slanted line, from 0.0 (at the base or start point) to 1.0 (at the endpoint). This guarantees that these points keep their relative position along the line, even if the length of the line varies. For example, the bottom of the red piece that is at top of the yellow base will be always at 0.33 along the line, one third of its length.
Notice that some faces of the parts of the column are parallel to the ground, (indicated in red in the image below) and some other faces are perpendicular to the axis of the column (indicated in blue).
The points that are located in planes that are appendicular to the axis can be used to host profiles for the forms. The points that are located in planes that need to remain horizontal, will need to host another point with a rotation parameter, and that second point will host profiles for the forms.
Now we create 2 families that will serve as profiles to create the forms. These are generic model families, work-plane based, not always vertical. One as a square, with a “Side” instance parameter, and the other one a circle, with a “Diameter” instance parameter. Then, we place squares or circles at the correspondent places, looking at the picture or sketch of the column, putting the circle or the square on the plane of a point, one at a time.
Then I have to create all the forms, selecting 2 adjacent profiles, square or circle, using an approximated value for “Side” and/or “Diameter’, and using the Create Form tool. First, I make all the forms without worrying for the sizes, just to see if everything is making sense. I can adjust all the dimensions and proportions later.
Then, I overlay the picture (or sketch) with the geometry. This allows me to see which parameters need to be adjusted. This is just an approximation, of course, because the elevation view in the family is at its true dimension, and the photograph has the distortion of the perspective, and because the height from roof to floor was just an estimation.
After adjusting the proportions, I obtain something like this, below. Even if some dimensions are not correct yet, now the family is parametric and serves as a design tool to explore variations. Now all the properties can be adjusted by parameters: inclination, sides of squares, diameters of circles, vertical distance, and location of points along the slanted line.
Adaptive Repetitions
In Part 1 of this article I showed some exercises about repetitions; simple repetitions of identical elements. But now, continuing my journey through the theme park, I found a gate that is inspired in a “stegosaurus”, with multiple “bony plates” along his “body”. These elements help me to explain the topic of adaptive repetition, which is a repetition of similar elements that are modified at each instance, based on a certain pattern that is driven by a formula.
Notice that the bony plates seem to grow from the ends toward the center. That is the pattern of this repetition. The bony plate starts small at one end, grows gradually as it approaches the midpoint, and reduces its size as it gets far from the midpoint.
Also, we could imagine that the body of the stegosaurus is not skinny as shown in this gate, but that his body follows a similar pattern, fat at the center, and thinner towards the tale and head.
Adaptive repetitions require 2 adaptive families. One contains the repetition and the other one the repeater. Let´s work on the family that contains the repetition.
In a new family, adaptive, in the plan view, I begin by creating 3 reference points. Let’s say that the distance from the first point to the third is 18 feet.
Then I select the three points, and use the reference > spline tool, to create a spline that connects these 3 points:
Then, I select the spline and use Divide Path, to divide the spline into a number of nodes that will be the hosts for the repeaters.
Thinking of the gate, and thinking of leaving the ends of the body of the Stegosaurus/gate without a bony plate at the ends, I set up the number of divisions as 17, and I apply an indent of 1 foot at both ends.
The repetition family needs to have a control point, an adaptive point. Therefore, I create a reference point close to the middle of the spline, and use Make Adaptive, to convert it into an adaptive point.
Now that control point, now adaptive, looks like this:
Creating the repeater for the form of the body
The repeater for the body of the Stegosaurus is a circle. But not just any circle. It is a circle whose radius is controlled by a formula. The formula must be in relation to a distance from one adaptive point to another adaptive point.
In a new family with the adaptive generic template, we create a circle, two adaptive points, and two dimensions, one to control the radius of the circle, and another one between the adaptive points to create that “D” reporting parameter that I mentioned above.
Notice that the repeater for an adaptive repetition has at least 2 adaptive points. Point 1 will connect to each node of the divided path. Point 2 will connect to Point 1 in the repetition family. Since that distance varies at each instance, the circle varies its radius as per the formula.
The circle is like the cross section of the Stegosaurus, and we want that the bigger the distance from each node to the control point, (at the middle of the spline), the smaller the circle. That’s why in the formula, we use a value that reduces the radius as the value of D increases.
The orientation of the repeater is always a challenge, and it is difficult to predict the right combination of orientation of the object (the circle in this case) in the repeater family, and the orientation of the point that hosts the circle. This takes several attempts, as it is difficult to understand this relation. In this case, the combination that works is to draw the circle on the horizontal plane of the Point 1, set the orientation of the adaptive Point 1 to the “Host and Loop System” option, and set the repeater family as “always vertical”.
Then, when you load the repeater family into the repetition family, follow these steps:
- Place the repeater by the method of “Place on Face” on one of the nodes of the divided path. It does not really matter which node you chose, but for clarity, let’s use the middle node.
- Since the repeater family has 2 adaptive points, you must place that second point on top of the “control point” or adaptive point 1 in the repetition family, like this:
Then, select the repeater family (the circle), and use the Repeat tool, highlighted below:
- Then, select the repetition of circles
- Click on Remove Repeater,
- Click on Create Form
Then, find the “control” point (the adaptive point in the repetition family), and move it away from the center, to vary the shape of the body.
Or, find the reference point that we put in the middle of the spline, and move it up. You can also move the tail and the head (the endpoints of the spline) in different directions:
Creating the repeater for the bony plate
Following the same principles, and with more time and patience, one could create another repeater family to (roughly) represent the bony plate, something like a little parametric cone like this:
Which can be placed on the nodes of the same divided path, repeat, and move points, to play with something like this:
Conclusion
Well, that’s more than enough for this Part 2. That is a good amount of material to digest. Thank you for reading me again, if you got to this point, of course. If you did, now you have a good amount of things to do with the generic adaptive template in Revit, for the next time you are challenged to do something that cannot be done with the generic methods.
We have seen a lot, and I still didn’t have time to talk about the roller coaster! Then, I hope there is a next time. J
About the Author, Alfredo Medina
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BIM manager, Revit advocate, speaker, instructor, blogger, video author, family maker, problem solver. I participate in several forums about Revit. I have participated in the Autodesk forums since 1997 (If I remember correctly). I was born in Cali, Colombia. I studied architecture there. I came to the US in 1999 to work for an architectural firm in New Jersey. Some five years later I moved to Florida. At the moment, I work for Universal Creative in Orlando, Florida. I have been a speaker at some events such as Autodesk University in Las Vegas (virtual event, 3 times), and in the Revit Technology Conference (Auckland, New Zealand, in 2013, and Melbourne, Australia, 2014, and will be in Toronto 2017). I speak Spanish, English, and an intermediate Italian. I enjoy writing, drawing, teaching, solving geometrical problems, riding my bicycle, listening to classical music, and watching soccer games and cycling races.
Contact information: Email: info@planta1.com
Linkedin profile & résumé: https://www.linkedin.com/in/alfredo-medina-64357255
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