Green Light for Cathenge Installation at Patricia’s Green!!!

Last Wednesday, October 19th, the San Francisco Department of Recreation and Parks issued a one year permit for Cathenge to be installed and exhibited at Patricia’s Green Park (Octavia and Fell streets, Hayes Valley). This is the green light, the permission, Cathenge has been waiting for! By October 31st 2022 Cathenge will be all finished and ready to receive the public.

Needless to say, the whole Cathenge Crew of collaborators and I are very excited. We are in the home-stretch of production. Many final tasks and finishing touches are being completed. The “Holofelinity Sound-Light Sculpture” is being refined and perfected. The base is being decorated with laser cut space cat themed motifs and metallic gilding. The cats are being given their final clear-coat of iridescent hi-gloss finish. So many details being coordinated, a concerted collaborative effort of a dedicated team of artists and technicians, an elaborate and meticulous vision on a monumental scale is being realized.

It has also been a concerted effort of SF City Officials from different departments, as well as engineers, insurance agents and other professionals to work through and process all the regulations, civic and legal requirements to bring a sculpture like this to the public. It is easy to take public artworks for granted, but behind the scenes; the large amount of administrative work required to produce them cannot be underestimated.

Here are photos and videos documenting the latest efforts of Cathenge in progress.

Staging all six Catoliths in their correct position at David Normal’s studio in Stinson Beach, California
Final Concept Drawing of Cathenge for Patricia’s Green
“Holofelinity Light-Sound Sculpture” (Interactive Harmonic Purring)
Cathenge 3D printing studio
“Saucer Cat” laser cut Design for Cathenge side panels
Decorative laser cut facia speaker covers with “Saucer Cat” motif

Kittolith 2.0

In February we completed the “New Prototype Kittolith” and debuted it at the Space Cat Cavalcade. This 5′ tall Catolith was printed by Re3D in Houston, Texas. The sound and lights were created by Theremin Barney, Artur Pyrogovskyi, and Aaron Winette. In this video I am demonstrating the motion detection based sound/light interactivity that Barney engineered using passive infrared sensors. The cat itself is a speaker. A kind of transductive speaker is affixed to the perimeter wall of the cat statue and the entire plastic cat vibrates to produce the sound. The sounds are solfeggio tones that Artur programmed in a randomized cycle to be triggered by the voltage signal transmitted from Barney’s motion detection circuit. This is still a work in progress, but we are developing this system to be used in the ring of six Catoliths that will be installed at Patricia’s Green.

Blue Sparkle Kitten Print

Today I printed out a small version of “Thanata” the Catolith of Death in sparkly blue-green irridescent PLA plastic. This is the first version of the Catolith that I’ve modeled with decorative surface embellishment. I modeled this in the subdivision surface modeler “Sculpt” of Cimema 4D 3D software. My intention is to use these surface details as the basis for painted decoration of the big Catoliths. This small print is a useful experiment in painting technique that can be applied on a much larger scale.

Printing Test with Modified CR-10 S5

“Dipping your toe in the water”.  The saying is something like that, right?  Well, in this case it is a plastic cat toe.

I’ve been running test prints of just the toe of the cat.  First on the smaller Ender 3 printer with smaller size nozzle and now on the larger CR-10 S5 printer with correspondingly larger gauge of nozzle.  I’ve modified this printer with a direct drive extruder and an improved bed heater.  This is the first print I’ve done with the large printer.  I am testing all of the parameters and specifications in preparation for replicating this with another 6 printers.  There will be a total of seven printers dedicated to producing cathenge.  I reckon one will be devoted to each section of the six height segments of the Catolith and the seventh for printing the divider components.

3D Printing Catoliths 2022

These feet of a “Mini-Kittolith” are one of the very first things I printed since resolving to undertake on my own the printing of Cathenge for Patricia’s Green myself. 

I’ve opted to print Cathenge myself. It’s a big undertaking – typically people print something the size of an action figure, but it’s possible to do much larger things, and so I’m printing all 6 Catoliths. Doing the printing myself gives me the latitude to experiment with the design and the technique and that is essentially what artistic control is about.

I was able to source high quality yet inexpensive large format 3D printers (Creality CR-10 S5) which give me a 500*500*500 mm build space to work with. I am setting up seven of these printers at my studio in Stinson Beach. Using all seven printers at once I estimate I can produce one cat in 3 days. I’ll begin production of Catoliths by the second week of April and hazard to guess I’ll finish all six Catoliths within a month.

Of course, I get to keep the printers which opens up a whole new world of artistic possibilities for me. Building on my long experience in 3D modeling, I envision new “Crazyological” sculptures 3D printed and embellished with paint, lighting effects, interactivity and/or kinetics. It’s quite exciting!

Cathenge at Patricia’s Green, Hayes Valley, San Francisco (Completed Project – Now Exhibiting)

Cathenge is now completed and on display at Patricia’s Green in Hayes Valley, San Francisco. The culmination of over a year’s continuous work by artist David Normal, and intensive collaboration and coordination with a talented team of builders and technicians has brought Cathenge to life. Below are some photos of the newly erected installation.

Below is an 3D visualization of the Cathenge Installation for Patricia’s Green. ADA (American Disabilities Act) regulations required that the tips of the star shaped pedestal upon which the cats are standing be truncated. Not only did this provide a more equitable and accessible experience, but it also improved the design.

Below are some of the plans and drawings used in proposing and designing Cathenge. Basically, these are the design strategies in place that have been refined by RBHU Engineering (Structural Engineers).

Cathenge Prototype in David Normal Studio Spring 2019

This 3D printed Catolith prototype “Kittolith”. Printed by Christopher Christensen. This prototype features motion activated interactive purring by Theremin Barney. Ultimately, we settled on touch sensitivity through “Capacitive Sensing” as the mechanism of interactivity for the large Catoliths at Cathenge, Black Rock City 2019.

Catoliths and Interactive Solfeggio Sound Effects

The effect I’d like to achieve with the Catoliths is similar to a set of windchines. Motion detection creates the chiming of the Catoliths. Each cat has an infrared sensor mounted in its chin and facing downward. This creates a cone of interactivity wherein a visitor to Cathenge will hear the cats “intone” their respective notes. Additionally, triggering one cat will trigger notes in the other cats (ideally, this is a random or semi-random pattern).

Six Catoliths

Thanata = 396hz = DO = Tonic C = Saturn

Fortuna = 417hz = RE = D = Jupiter

Lyrata = 528hz = MI = E = Mars

Erotica = 639hz = FA = F = Earth

Lunata = 741 = SO = G = Venus

Solara = 852 = TI = A = Mercury

The above equivalencies connect each catolith to a specific solfeggio frequency. Above (396 – 852) is the solfeggio scale used in Gregorian chanting.

Gregorian Chant:

 Because planets with larger eccentricities have a greater variation in speed they produce more “notes.” Earth’s maximum and minimum speeds, for example, are in a ratio of roughly 16 to 15, or that of a semitone, whereas Venus’ orbit is nearly circular, and therefore only produces a singular note. Mercury, which has the largest eccentricity, has the largest interval, a minor tenth, or a ratio of 12 to 5. This range, as well as the relative speeds between the planets, led Kepler to conclude that the Solar System was composed of two basses (Saturn and Jupiter), a tenor (Mars), two altos (Venus and Earth), and a soprano (Mercury), which had sung in “perfect concord,” at the beginning of time, and could potentially arrange themselves to do so again.

Musica universalis (literally universal music), also called Music of the spheres or Harmony of the Spheres, is an ancient philosophical concept that regards proportions in the movements of celestial bodies—the Sun, Moon, and planets—as a form of musica (the Medieval Latin term for music). This “music” is not usually thought to be literally audible, but a harmonic, mathematical or religious concept.

The idea continued to appeal to thinkers about music until the end of the Renaissance, influencing scholars of many kinds, including humanists. Further scientific exploration has determined specific proportions in some orbital motion, described as orbital resonance. – Ref: Wikipedia



Sit, Jessica. Look how the floor of heaven
Is thick inlaid with patines of bright gold:
There’s not the smallest orb which thou behold’st
But in his motion like an angel sings,
Still quiring to the young-eyed cherubins;
Such harmony is in immortal souls;
But whilst this muddy vesture of decay
Doth grossly close it in, we cannot hear it.

– Shakespeare, “The Merchant of Venice