Stage 1 – Modeling a Parametric Structure (Figure 1)
For the definition of the controlling geometry, the designed form can be stretched in the X, Y, Z directions to make the structure longer, taller, and wider. There is also functionality to change the curvature of the structure’s arc ribs. Placement points are created along the controlling geometry consisting of the curves. These structural ribs support the shelter and the panel surfaces act as a protective skin for the shelter. The design is parametrically resizable and scalable such that the structure’s length, height, width as well as the curvature and length of the main controlling curves can be flexed with sliders. The base curve length and spacing definition are fed in as inputs to points for line definition. The point on curve is used to grab the reference point, followed by using the vector to move it. Sliders are also used to define the X, Y, Z components of the vector. Once the arc (curve) is defined for each of the eight specified ribs, these are inputs into the merge node to create the list of construction curves. The output of the merge node is divided into placement points as well as the loft surface with construction curves. The number of structural supporting ribs and the size/spacing of the panels on the shelter surface can also be flexed using sliders. The number of panels can be determined by adjusting the number of longitudinal and transverse segments. The surface is divided into a grid and panelized. For enhanced customizability, there are 3 options of panels (Quads, TriB, Squads) and a slider for scaling factor for the LunchBox paneling nodes. Rib placement curves (both transverse and longitudinal) are defined and used to create capped pipes. These capped pipes are then merged with the surface panels to form the resulting geometry shown in Figure 1.
Stage 2 – Transforming Your Geometry (Figure 2)
Extending upon the design proposed in Stage 1, the ribs serve as the structural foundation and can be dynamically changed to apply a mathematical transformation on the arc curves to become sine-wave based functions. The output from the arc curve node is fed into a block of nodes that evaluate the function and perform mathematical operations followed by moving the geometry and interpolating the curve; this is repeated for each of the original arc curves, The resulting sine-wave based curves are merged. Frequency and amplitude of these sine waves can be flexed using sliders to update the geometry’s form.
Reducing the wave frequency or amplitude to 0 returns the shape of the geometry to its original form. Maximizing amplitude increases the peak-to-peak height while minimizing amplitude decreases the peak-to-peak height. Increasing frequency of the sine wave leads to faster oscillation while decreasing the frequency leads to slower oscillation. The interval for wave amplitude was set to include negative and positive values but the interval set for frequency was set to only positive values (since negative values would reverse phase direction). The limits were adjusted for these parameters to stay within the specified interval to achieve the desired structural shape shown in Figure 2.
Stage 3 – Applying Your Form at Different Scales (Figures 3 (a, b, c))
The parametric logic of the design was updated to accommodate varied scales. In the grasshopper file, a new block of nodes was added to include a scaling factor that allows specification of a target length and current length of the base curve. The current length is used in the original base curve definition. The target length is used to accommodate the varied scales of the geometry. The ScaleNU node allows the entire structure to be re-scaled according to the scale factor and keep the same aspect ratios of the different components of the overall geometry.
Examples of the structure at small, medium, and large scale for a base curve length of 30, 150, 400 feet respectively are shown in Figure 3 (a, b, c). At a small scale, the structure can be used as a pedestrian shade canopy or bus stop where the panels mainly act as shade or enclosure from rain. At a medium scale, it can be used as a transit platform canopy or outdoor plaza. At a large scale, it can be used as an arena or concert hall. Depending on the desired application or scale, the sliders for various parameters (e.g., size or number of panels as well as the radius or number of ribs) can be flexed accordingly.
Creative bonus features shown in Figures 4 (a, b, c) (see file: 4units_StephanieChang_Module3_Stage3_creative_bonus_colored geometry_panel & frame options)
- Application of color to the final structure: Determined the list length of the output geometry from Scale NU node and fed this into a Series node. Nodes for bounds, domain, and deconstruction of domain are used. Values are also remapped to serve as the parameter for the color gradient range. Preview node is used to display the colored geometry.
- Multiple options available for panel shape (TriB, Quad, SQuad) or frame selection allow for high user-customizability of the geometry
- Unique shape for the parametric structure with high modifiability to flex multiple parameters (amplitude, frequency, number and size of ribs and panels, spacing between the ribs, positioning of ribs, color, etc.)