Designing Associativity - Assignment 317. February, 2010Joel Letkemann

The studio project is centred on the development of a CNC robot, which creates molds in sand, as an ecological alternative to standard molds used in making concrete wall panels and other building components.

void turn_right(){ digitalWrite(motor_left[0], HIGH); digitalWrite(motor_left[1], LOW);

digitalWrite(motor_right[0], LOW); digitalWrite(motor_right[1], HIGH);}

void motor_stop(){ digitalWrite(motor_left[0], LOW); digitalWrite(motor_left[1], LOW);

digitalWrite(motor_right[0], LOW); digitalWrite(motor_right[1], LOW); delay(25);}

void drive_forward(){ digitalWrite(motor_left[0], HIGH); digitalWrite(motor_left[1], LOW);

digitalWrite(motor_right[0], HIGH); digitalWrite(motor_right[1], LOW);}

The Sandbot is essentially scale-less; it is able to create molds of any size, constrained only by the size of the surface it is working on.

-17.015-28.827-35.59-25.855-33.868

-36.877-58.454-43.283-10.07-38.918

-58.129-60.503-78.236-72.861-67.231

-20.914-36.563-42.744-47.452-54.79

-56.803-55.497-44.282-29.166-30.2

-54.327-65.768-67.009-63.146-57.521

-5.98-19.076-35.244-48.211-49.821

-33.891-28.892-54.716-9.617-14.147

-16.257-14.406-11.982-15.273-33.798

I used Grasshopper, a plug-in for Rhino, in order to defi ne a ‘g-code’ for any surface i could wish to develop. This returned a set of z-coordinates, which were multiplied by the radius of the mechanism, in order to gain the rotation in degrees, which was fed into the code for the machine.

Interface with Cadenary

Active Statics Screenshot Cadenary Screenshot

Catanary Arch, on analogy with St. Louis’ Arch, with Grasshopper Defi nition

Because of the proposed material, concrete, which is good in compression, I investigated catanary geometry, specifi cally the programs Cadenary - developed by Axel Kilian - and Active Statics - developed by Simon Greenwold.

Cadenary geometry, returning a “chain” of 7

linksCadenary’s approximation

of a catenary curve

A different defi nition in Grasshopper. While not self-supporting in construction, this structure has a curved surface on one side, while still maintaining the constraints set for the project. This defi nition allows one to change the thickness of the membetrs, thicker at the bottom, while thinner where less material is needed.

Catanary Mesh, with One Planar Surface

The fi rst step is to divide the surface according to the desired number of ‘bricks’ in the dome. In order to make sure these were appropriately ‘tilted,’ I divided the original surface into 4 quarters, with the intention to rotate them again. These surfaces were then made into planar surfaces.

The fi rst step is to divide the surface according to the desired The fi rst step is to divide the surface according to the desired number of ‘bricks’ in the dome. In order to make sure these number of ‘bricks’ in the dome. In order to make sure these were appropriately ‘tilted,’ I divided the original surface into were appropriately ‘tilted,’ I divided the original surface into 4 quarters, with the intention to rotate them again. These 4 quarters, with the intention to rotate them again. These

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2

The edges of these 2 sets of surfaces, 9 on the original dome’s surface, and 9 planar surfaces at varying depths, were lofted, in order to create the sides of these bricks.

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The edges of these 2 sets of surfaces, 9 on the original dome’s surface, and 9 planar surfaces at varying depths, were lofted, in order to create the sides of these bricks.

3

These planar surfaces were offset according to their distance from the ‘ground,’ as a dome supports much less weight at the top than at the bottom. the corner points of the original 9 surfaces on the dome were projected to the center of the original surface, projected onto the ground plane. These intersections were used as the corner points of 9 new surfaces

Finally, the quarter of the dome was rotated, in order to complete the dome.

22 These planar surfaces were offset according to their distance These planar surfaces were offset according to their distance These planar surfaces were offset according to their distance

The edges of these 2 sets of surfaces, 9 on the original dome’s surface, and 9 planar surfaces at varying depths, were lofted, in order to create the sides of these bricks.

Finally, the quarter of the dome was rotated, in order to

This defi nition, then, returns the values for production, as a series of points on a contour. The logic trees for this defi nition are also adapted to

.csvExcel

This next iteration tried to accomplish the same logic with a more complex morphology. Instead of a single surface, this morphology was composed of several surfaces, as well as openings.

The mesh is fed into a function which remaps the value of certain verticies on the mesh, and their distance to the ground.

Those offsets which are greater than a specified number, provided by a slider, are closed entirely. These are, invariably, higher up in the structure, and thus are closed to provide a ‘roof.’

Those faces of the mesh that are less than that number are fed into Weaverbird’s triangulate mesh component, and then into the Weaverbird hole component, which is offset by the specified value.

As i was having trouble defining an offset for this definition; Grasshopper was having trouble with the many surfaces i added, I moved this mesh in the z-direction, and lofted the resulting wireframes.