The animation illustrates how the Shape Optimizer automatically evaluates various shape modifications, within the imposed constraints of surface depth, width and motif, from a specified number of sources (x) to a specified number of observers (square). The first three lines (with the changing numbers) indicate the standard deviation from the desired performance in dB, including spatial penalty constraints. The standard deviations with no penalty are shown to the right. The last line indicates the number of solutions found thus far, the number of iterations and the time in seconds for each interative calculation. The three curves shown are the current shape (teal), the best shape found thus far (black) and the worst shape found thus far (orange).

Acoustics was an integral part of classical architecture. Columns, balastrades, balconies, statuary, and other forms of relief ornamentation satisfied both architectural and acoustical requirements. While these types of surfaces offered useful sound diffusion, by today’s standards they are far from ideal. With the advent of ever increasing computer processing power, we can now predict, measure, and optimize the scattering from potential diffusing surfaces. RPG® has taken this capability and developed a software tool to optimize the scattering from various surfaces to provide an expanded palette of complementary acoustical surfaces for contemporary architecture. This process is accomplished by combining multi dimensional optimization with accurate boundary element scattering prediction.

Problem
Architectural designs and acoustical requirements are often at odds which results in compromises between the two. Acoustical shape design software that simulatneusly addresses both needs would be desirable.

Solution
RPG® developed the Shape Optimizer™ to acoustically optimize the desired shape while maintaining the desired motif. RPG® offers this as a design service to the specifying community. The program combines powerful Boundary Element Method algorithms with multi dimensional optimization techniques in an iterative approach that minimizes the standard deviation of the scattered sound pressure level at all receivers from all sources over a specified bandwidth. The program requires source and receiver coordinates, desired shape function, symmetry and other constraints, and allowable width and depth. The program exports a .dxf file for CAD/CAM manufacture. The shape can be fabricated in wood, fiber reinforced gypsum, or concrete.

Shape Optimization
First, a desired surface shape is expressed mathematically.

Surface to be Optimized.
Next, the sound pressure scattered by this trial surface from any number of sources is calculated on a field mesh, which contains the locations of all of the receivers. The standard deviation of the scattered sound pressure is determined at one-third octaves over the desired bandwidth.


Calculated sound pressure on a field mesh of all receivers for one of the group of sources being modeled at 1KHz.
A plot of this average standard deviation from all of the sources versus frequency is called the Diffusion Spectrum.


Diffusion Spectrum monitors scattering performance.
Finally, the program evaluates hundreds or thousands of potential surface shapes, while maintaing the original motif, until it finds the shape with the lowest mean and standard deviation diffusion response.

Home: Products: CHAOS

The Collaborative Holistic Acoustical Optimization System