Arch 635 Projects: 2010

Parametric model and API – Ribbed Slab

This project was basically a continuation of project-1 which was a ribbed slab. In this parametric model every parameter was user driven. The ribs were created with the help of voids such that the ribbed slab could be manipulated to be pergolas.

The issue that was faced here was that when this parametric roof was a part of a project as a roof, the dimensions of the roof would not automatically change with the dimension of the room. By using Revit API programming, this can be achieved which is my second project.

parameters that can be manipulated in the ribbed slab parametric family

view of the parametric slab of project 1

The application also calculates the depth of the ribbed beam with respect to the breadth of the room by using the formula breadth/20. The program checks the new ribbed beam depth to the overall slab depth. Ribbed beams are part of the slab and cannot be deeper that the depth of the slab. If the new ribbed beam depth is greater than the overall slab depth a message pops up displaying the required ribbed beam depth for that particular span and the existing slab depth and the model is not updated else the ribbed slab gets updated according to the size of room and the current roof dimensions, ribbed beam depth and wall heights are displayed in a pop up window.

Since the walls are attached to the bottom of the slab and don’t update automatically when walls are moved, the application also updates the height of the wall with respect to the total slab depth.

Instructions to run the application:

The ribbed slab acting like pergolas for the room.

The ribbed slab thickness is set to zero so that it acts like pergolas

When the breadth of the room is initially changed the roof will stay the way it is.

view of the model when the room dimension is changed without running the API program

When the API program is run, the program calculates the new depth of the ribbed beam the roof gets adjusted to the size of the room and the depth of the ribbed beam is calculate with respect to the breadth of the room. It also returns the value of the new room size, depth of the ribbed beam and height of the wall. If the overall depth of the roof is changed in the parametric model, the wall heights get automatically adjusted.

view of the ribbed slab that is updated according to the dimension of the room

view of the slab when the model does not get updated if the ribbed beam depth is greater than the overall slab depth of the ribbed beam. A message box pops up with the values of the required ribbed beam depth and the existing overall slab depth.

My experience with Revit has been a struggle in a way. This is my first time using the software and I have had some issues that I struggled with but I feel that once you get the hang of it, it is a lot more comfortable. This model is schematic in way. Since the project is a little big I could not really get too much into the details due to time constraints.

Project Description

This is a model of a mixed use building situated in Fenway Park Boston and is my studio project from last semester. The building has four main uses namely commercial on the first two levels facing the Fenway park. The four levels of residential space share a common wall with the commercial space but face the existing apartment at the back. The third and the forth levels are designed as a Hotel for the visiting Baseball team and the office space is designed as a tower.

Process & Issues

I started off by creating the site using the site tools which was quite straightforward and did not have any issues with it. I brought in the .dwg file as an underlay to model on. Since the walls in my design were a different thickness than the default I created new wall type by duplicating the wall that closest matched my requirement. I did the same with the slabs as well. Since some of my walls and slabs are red, I had to make a different type for those. Building the slabs and walls were quite simple and once I figured out how to detach and attach wall to any given slab, the modeling process was a lot faster. The only other place that I got stuck was changing a panel in the curtain wall to a door. Revit would not allow me to load it directly and it took me a while figuring out how it worked. It was the same with columns. Though I have structural circular and square columns I could not load the column families under structural columns. I could only load then as architectural columns. There should be a more intuitive way to handle this situation where only the eligible families/component should be made available for loading into the project.

Another issue that I faced was when I tried to bring in a stetchup file with the site context it made the file extremely heavy and slowed down the system to the point that I just decided not to put in the context at this point. I am also not too comfortable with the rotate tool. Revit should allow us to pick the point of rotation as default similar to AutoCad and not assume it as the center.

On the whole learning how to model in revit has been a learning process and I am hoping that I will get comfortable working with it with time. Parametric modeling in Revit is quite fascinating, another first for me. The fact that you can get clean floor plans and a rendered model all in the same software is a welcome change from the software’s that I have used in the past.

Parametric Modeling

The parametric model that I have designed is a ribbed slab. I have used the concept of a nested family. This model allows for variation in slab thickness, different edge beam thickness and different spacing between the ribbed beams. This could also be used to create pergolas of different spacing and depth.

The idea behind this design was to use a series of voids at specific distance in a slab to create beams as a result.

1. I started off by creating a void family and locking the edges to reference plane so that the dimensions of the void could be controlled.

2. I created my main family using a generic template where I created a slab using the extrude tool. By aligning and locking the edges of the slab to reference plane defining the length and breadth of the slab, the dimension of the slab can be changed.

3. I fixed reference planes to mark the width of the edge beams and assigned parameter to it so that the width of the edge beams can be modified.

4. I loaded the void family into this slab family. By linking the length parameter of the void family to the effective width in the slab family the length of the void will be equivalent to the clear span of the ribbed beams.

5. The voids are arrayed to create the ribbed beams. The position of the first and the last void is locked with reference to the edge beam. The number of voids is calculated as shown in the figure.