TWISTED SCULPTURE | CAD

MAIN GOAL & INSPIRATION

The goal was to create a structure that is twisted in itself and varies through different parameters, resulting in a dynamic art piece. The structure was designed to be visually interesting while also having complexity and an interactivity by changing different input values. The outcome is a virtual artwork with an organic, parametric quality.

I got inspired by different fabrics and parametric sculptures:

TUTORIAL

STEP 1 – CREATING THE BASE

The first step was to create a base. I decided to make the shape a circle to have another twist and create an interesting dynamic. Therefore, I used an Arc, setting the plane at the XY origin, defining a radius, and specifying an opening Angle, as I didn’t want a closed circle.

Afterwards I used the Perp Frame command, to generates orthogonal coordinate systems along a curve, aligned at a right angle to the Arc. This allows to align objects along the Arc later.

STEP 2.1. – POSITIONING A LINE ON THE CURVE

In this step, a SDL-Line is positioned along the Arc that was previously created in, with its location and orientation determined by the frames generated in the earlier step using the Perp Frame command.

An Unit vector, Position on the Curve and a Length are given to define the direction of the line, control its length and define the line’s position on the Arc.

STEP 2.2. – REMAPPING

In this step, a Remapped numbers command is used. It scales the original values to fit within a new domain, adjusting the positions along the arc. This specify the distance and placement of objects along the curve.

The Frames generated earlier, using the Perp Frame command, align the objects perpendicular to the tangent of the arc. This alignment, combined with the remapped values, results in objects being placed in a curved, semi-circular pattern along the arc.

After connecting that to the radius of Arc, the outcome is the creation of semi-circles around the Arc.

By changing the number of the Points on Curve command, the position of the line changes, and with it, the entire structure. This is one of the parameters that can be adjusted later to change the shape of the art piece.

STEP 3 – POSITIONING A SECOND LINE ON THE CURVE & REMAPPING

In this step, a second SDL-Line is created to define the opening angle and control its orientation. The line’s position and length are adjusted using remapped values, similar to how the first line was positioned earlier but this time with a Radians command as the domains start and end.

STEP 4 – SERIES

In this step, a sequence is generated, which is used to create multiple repetitions of the lines around the arc.

The Series command generates a sequence of values based on the parameters Step and Count.

The Step here controls the angle, and the Count defines how many of these lines will be placed along the arc. This i connected to the number of Frames that was defined earlier.

After the circular lines are placed along the arc, the Rotate command is applied. This step is responsible for rotating each of the circular lines around a point with the Angle, given to the Series command. The Plane “input” of the Rotate command is again connected to the Frames that were defined earlier.

The rotation gives the design a more organic and dynamic appearance, as it transforms each line’s position and orientation around the Arc.

STEP 5 – LOFT

In this step, the Loft command is applied to the series of Arcs created before. The component generates a surface by connecting them.

By playing around with the different parameters, the shape of the sculpture can be adjusted:

INTERIM RESULT

As shown in this screenshot, the creation of the shape is done. The following step is used to change the surface of the structure to create the desired outcome.

STEP 6 – SURFACE

After the final loft is created, a Deconstruct Brep command is applied. This is done to allow modifications to individual parts of the loft, in this case the faces. These faces are then grafted and processed using the Divide Domain and IsoTrim commands to break the surface down into a shell-like structure. The V Count determines the number of divisions.

Next, another Deconstruct Brep command is applied to refine the surface using the Offset Surface command for better precision. This allows the final shape to be generated using the Ruled Surface command.

ISSUES

At the end, I tried to change some parameters to produce different shapes but that was quite demanding because it worked so slow. Looking at the Profiler, especially the last surface commands were the reason for that:

But because I wanted to keep the slim structure, I just disabled the last part to make my changes and enabled it after my changes again.

! BY THE WAY: TOOLBAR !

At this point, it’s also worth mentioning this toolbar. Here, you’ll find additional modes that can speed up or improve the display.

1. The display modes: There is even an option to not display the object in Rhino at all, which is useful for very complex geometry. Then, there are the Wired and Shaded options, which are similar to what we know from Rhino.

2. The preview modes: there are two modes related to the amount of display. The blue mode draws a preview boundary on the canvas to exclude objects. The green mode is a useful feature for tracking what your definition is doing at different stages of the process, without having to switch off all previews and manually turn individual ones back on as you go. The half-white/orange ball represents the document preview settings, where you can modify the colors – including transparency – that Grasshopper uses to display objects in the Rhino viewport.

3. The quality modes: Finally, the last light-blue symbol is the most interesting for this case. Here, you can adjust various quality settings and switch the entire document to a low-quality preview.

I used the Wired-Mode and the Low-Quality-Settings to make my geometry faster to adjust.

STEP 7 – COLORS & MATERIALS

The final step was adding colour and materiality to the geometry. I experimented with different approaches:

Simple Color → using the Custom Preview + Color Swatch
Rhino Material → using the Custom Preview + Panel (by simply copying the name of the Rhino-Material into a Panel in Grasshopper, the Material gets attached to the geometry)
Create Material → using the Custom Prewiev + Create Material (by adding the Create Material command, different parameters can be attached and changed: Diffuseness, Specularity, Emissiveness, Transparency, Shininess. Interesting here is especially the Transparency)

In the end, I baked all the elements and arranged them into a cohesive ensemble in Rhino, preparing everything for the final shots.

! BY THE WAY: SOLUTIONS !

In the top menu bar, there is the Solutions section.

Here, states can be saved when working with a complex definition, so calculations don’t need to be restarted every time small changes are made. It’s also a great solution for saving intermediate stages while still being able to experiment further. The current model’s state can be saved, and then work can continue on a second option. To return to option 1, simply go to Solutions -> Restore State and restore the previously saved and named state. And don’t forget to save Option 2 as well! ;)