A parametric model and script workflow to conduct daylighting simulations

 Description

In this project, a parametric model of a windcatcher within a generic building with a double-loaded corridor configuration was modeled within the Project environment in Revit. The model from Project 1 was used as the starting point. The model consists of a “Test Room”, which has a windcatcher attached to one of its sides, a hallway in the center, and another room on the opposite side.  The model was constructed using the Floor, Walls, and Roofs categories. Generic families of each category were used. Reference planes and dimensions were used to establish the different parametric relationships between the design parameters of interest. Several openings were modeled in the windcatcher and on the opposite side of the Test Room using the Opening families.

Using visual programming tools, a program was generated that enabled the user to easily manipulate the geometry of the model and conduct daylighting simulations. The RhinoInsideRevit plug-in was utilized to link the parametric model made in Revit to the daylighting simulation plug inside Rhino Grasshopper. The ClimateStudio (Solemma LLC) plug in was used and integrated into the algorithm to conduct the daylighting simulations. The result of the project is a parametric model prototype and Grasshopper script that enables the user to easily test the daylighting performance of different configurations.

The results of future research to be conducted with a more developed version of this prototype could potentially serve as guidelines to incorporate windcatchers in real buildings. Although this project was mainly intended for research purposes, ultimately it is also important to consider the aesthetic properties of this architectural component. For the last part of the project, the AI tool called Project Veras was used to explore different renderings to help visualize how this architectural element could be implemented in a real building design.

Different configurations of the parametric model.

 

 

Global Parameters

The initial model was generated using Revit. The parametric model is defined and manipulated using global parameters, as shown below.

·       Bmin Height: This parameter controls the minimum height of the roofs of the whole building.

·       BWidth: Controls the width of the whole building.

·       ExteriorOpeningHeight: Controls the height of the outlet openings in the Test Room

·       ExteriorOpeningWidth(report): Reports the width of the outlet openings (distance between reference planes). This parameter is linked to the Width parameter of the Opening family to make the opening width adjust to the Building Width.

·       HW Width: Controls the width of the hallway between the rooms.

·       TR Depth: Controls the depth of the Test Room.

·       TR Max Height: Controls the Height of the roof to generate a one-slope roof if needed.

·       TR RoofGrade: Calculates the grade(slope) of the Test Room roof. This parameter is linked to the Slope parameter of the roof, so it is adjusted automatically.

·       TR RoofSlope (report): Calculates the slope of the roof in degrees.

·       WC Depth: Controls the depth of the windcatcher.

·       WC Height: Controls the height of the windcatcher.

·       wc height: this parameter is the one that adjusts the reference planes, it is determined by a formula to be able to measure the windcatcher height from the roof level and not the interior ceiling level.

·       WC InletOpening Height: Controls the height of the windcatcher inlet opening.

·       WC InletOpening Width (report): Reports the width of the inlet openings (distance between reference planes). This parameter is linked to the Width parameter of the Opening family to make the opening width adjust to the windcatcher width.

·       wc inletopening height: This parameter controls the height of the windcatcher inlet opening. It responds to a formula that ensures that the height of the opening does not surpass the total height of the windcatcher.

·       WC OutletOpening Height: controls the height of the windcatcher outlet openings, which open in the Test Room.

·       wc outletopening height: controls the height of the windcatcher outlet openings, which open in the Test Room. This parameter adjusts the reference planes. Is determined by a formula to ensure the opening height does not surpass the roof height.

·       WC OutletOpening Width(report): Reports the width of the outlet openings (distance between reference planes). This parameter is linked to the Width parameter of the Opening family to make the opening width adjust to the windcatcher width.

·       WC RoofSlope (report): Reports the slope of the windcatcher roof.

·       WC Width: controls width of the windcatcher.

·       wc width: adjusts the distance between reference planes to control the width of the windcatcher. Is determined by a formula to ensure windcatcher width does not exceed the building width and leave space for access into the Test Room.

·       WWR Depth: controls the depth of the room on the opposite side.

·       WWR MaxHeight: Controls the Height of the roof to generate a one-slope roof if needed.

·       WWR RoofGrade: Calculates the grade(slope) of the Windward room roof. This parameter is linked to the Slope parameter of the roof, so it is adjusted automatically.

·       WWR RoofSlope (report): Calculates the slope of the roof in degrees.

 

 

Grasshopper Script and Daylighting Simulation

This image shows the entire script developed in Grasshopper to parametrically control the windcatcher configuration and conduct the daylighting simulations.

 

 

This is a typical module used to retrieve the geometry of the Revit model by categories. A Python script module is included to bake the geometry into Rhino if needed.

 

This group isolates the walls of the windcatcher from the rest of the walls that are retrieved from the Revit model under the same category. It is used to assign a different material to the interior of the windcatcher.

Lids were created for the Test Room exterior openings to be able to study the daylighting effect of the windcatcher. The lids adjust parametrically based on the geometry of the Revit model.

 

 

 

These two groups retrieve and update the roof slope parameters from the Revit model.

 

 

 

This group is used to assign material properties to the selected geometry. In this case different materials were assigned to the Roofs, Ceilings, Walls and Floors.

 

This part of the script generates the sensor grid within the room to conduct the simulation using the floor surface of the Test Room. A unit conversion node is used because the ClimateStudio plug-in operates in the metric system by default.

This group of nodes retrieves the global parameters from the Revit model and enables their adjustment through the use of an input value.

The final part of the script constructs the daylight model and runs the simulation. In this case, a point-in-time simulation was conducted. The nodes on the lower left enclosed in a group (purple rectangle) generate the date and time parameters required. The last nodes on the script retrieve the results and display the numerical results, such as the readings from every sensor and the mean and median values of illuminance.

 

 

 

Simulation results as seen from the Rhino window.

Limitations

Limitations in the proposed workflow were identified throughout the course of the development of the project that required workarounds and compromises. The initial idea was to control the parametric model using Dynamo. A significant obstacle was found in the “GlobalParameterSetValue” node. Apparently, this node is bugged, as it does not update the numerical value of the global parameters. After some tests, it was discovered that it does updates text-based global parameters. This limitation was resolved using the “Global Parameter” node from RhinoInsideRevit.

 

It was intended to incorporate optimization tools such as Galapagos into the Grasshopper script. This would have enabled the automatic optimization of the windcatcher. It was discovered that updating the parameter values within Grasshopper would automatically update the Revit model, but not the Rhino model. To update the Rhino model, it is necessary to manually click the “Recompute” button. With this limitation, running the automatic optimization process through Galapagos was not feasible, as it requires the Rhino model to be updated automatically.

 

Experiments with Project Veras

Below are some of the results of the experimentation with the tool. The “creativity” and “Style” parameters were set to 95 and 80 respectively. This was decided based on the simplicity of the model since it is representative of a generic building. The increased values allowed for the tool to come up with its own visualizations that better resemble real buildings. In the experiments, the following prompts were used:

 

#1: ornamental windcatcher, in a tropical setting, concrete building, concrete wind tower

#2: ornamental windcatcher, in a tropical setting, white concrete building, concrete wind tower, in the style of aires mateus

 

#3: ornamental windcatcher, in a tropical setting, white concrete building, concrete wind tower, in the style of alvaro siza

 

 

 

 

#4: ornamental windcatcher, in a tropical setting, white concrete building, concrete wind tower, in the style of frank lloyd wright

 

 

#5: ornamental windcatcher, in a tropical setting, white concrete building, concrete wind tower, in the style of louis kahn

#6: tropical building with shading devices, ornamental windcatcher, white concrete wind tower with big opening, horizontal openings

 

#7: futuristic wind tower, futuristic windcatcher, futuristic white tropical building, metallic wind tower

 

 

#8: ornamental windcatcher, in a tropical setting, beautiful white concrete building, concrete wind tower

 

#9: wind tower with louvers, windcatcher with louvers, wind tower with glazed openings, tropical architecture

 

#10: ornamental windcatcher for natural ventilation, in a tropical setting, beautiful concrete building

 

 

The initial attempts helped to calibrate the final values of the creativity and style parameters. Having the lower values did not produce the type of image that was desired due to the simplicity of the model. Research can be very valuable to inform the process of architectural design, but the aesthetic aspect of a building must also be taken with great consideration. A building’s performance can be very well studied, but that should not result in an aesthetically unpleasant building. This experiment was very interesting as it helped to visualize the aesthetic possibilities of the windcatcher. It was noted that for some of the prompts, the program was unable to recognize the windcatcher, as it did not generate an image with the specified characteristics, such as “wind tower with louvers”.