In cartoons and movies, animation is achieved by rapidly displaying a sequence of pictures that have a common structure. This method creates the illusion of movement, because our brains will, as they are used to, reconstruct the pattern of motion from the static pieces.

How many frames

As we are going to animate an object, we will make it follow a curve. We need, therefore, to sample this curve in a number of (small) intervals. The number of intervals will determine the number of final frames we produce. If you plan to show your animation, later, on a TV screen, then you can take the frame rates of the PAL or NTSC systems: the European PAL has 25 frames per second (fps) and the American NTSC 29,97. If you plan to show your video online, you will need relatively fewer images: at least 18 fps, but most times 24 or 25 fps.

• For a European minute, therefore, the computer will need to render (60 s * 25 frames/s = ) 1500 frames.
• Similarly, for an American minute we will need (60 s *  29,97 frames/s = ) 1789 frames.

Subdividing the curve

To make the movement better controllable, we can, instead of subdividing the curve by Euclidean distance, evaluate it at a fraction of its domain (in its own parameterization). We will therefore be able of applying a weight to a control point, and it will influence the speed in proximity of the respective knot.

• A higher weight coefficient “slows” down the movement in the area.
• Two or more control points close to each other will make the animation basically stop for some time.

Moving the objects

RhinoScript gives us a number of methods to define the position of objects. For example, we can calculate the volume centroid of closed Breps, or the area centroid of open meshes. We will use these points to define the original location of our objects (O).

Because we want to follow a curve, we will need to move the object to the curve beginning, or S. For each frame, we will move by a t parameter farther on the curve. To avoid small summing errors, the script takes again the original coordinate and then sums the vector OS and SN, and does NOT move every time from the previous location (P) to the next (N). This would be subject to errors for small numbers, or for many frames.

Download

• Draw a curve, then run animator.rvb first and activity.rvb at last.

Implementation

animator.rvb
The animation details like the ID of the object we move and the original position are saved in a class called animator. As the namespace for VBScript is shared, we can define the class “animator” only once. Therefore, you can load the animator once for every Rhinoceros session. The class does the job of finding out which type of object we are dealing with on its own, so we just need to feed it an ID after initialization with the method setUp(). When we destroy the object, such as in the case we stop the script by pressing ESC or we are finished with our script, the object original position will be restored.

activity.rvb
The activity file will create one sphere and look for the first instance of a curve in the document. Make sure that it can find it. Then, it will make the sphere follow the curve in 750 frames. The constant DontRenderUpTo will skip the rendering part of the loop for all 750 frames.

Other examples

Many other ways to achieve motion in Rhino are explained on the Grasshopper tools page, at the renderAnimation link.

A wall is usually constructed as an entity that separates an interior from an exterior, leaving the exchange of air and light to the parts called windows. The motivation for this is notably the idea of shelter; that layer of separation between the human skin and the elements.

This little experiment wants to challenge this assumption and proposes a small component that is capable of sensing the presence of people. When someone is close to the wall, the partition become more porous: it allows the outside of the wall to see the interior.

At this time, light and air are allowed to come in. Additionally, this can constitute a manner of showing the presence of inner activities in a public building.

Behind the scenes

Visit adding motion in RhinoScript to learn how to put together a similar animation.

I am just back to Delft after having visited Barcelona to participate as a Rhino educator to McNeel’s RhinoScript workshop. Luis Fraguada of Live Architecture Network was the instructor and showed us some useful techniques for geometry construction and data visualization. I developed one of the script of the class a bit further and came up with this DNA helix.

Download the code: dna.rvb.

Download the source code: sakura.rvb.

“Option Explicit” is a series of scripts developed in collaboration with Ryoko Ikeda that deals with organic, abstract form and contemplates experiments that have been dealt with in aspects like geometry, light and shadows.

The intermediate goal is computationally explore shape creation, using the implementation of VBScripting that is offered inside Rhinoceros 4.0. The more far-seeing goal is to investigate algorithmic relationships among entities that usually surround us and re-establish their creative articulations, to simply allow us to deal with complexity.

Many things in nature grow from little to big. In fact, many people, when asked to name things that shrink, cannot normally name any for some time. But how does a tree actually grow?

Lindermayer was also fascinated by this question and develped a whole set of explanations, as a part of wider sintax-free grammars, to explain it. L-systems explain the groth of trees through a simple, unfolding, enlargement process, that we can imagine as the restarting every spring.

“Just a small change in the script of The crown and we get closer to an autumnal view.”

Download the source code: tree1.rvb.

“Option Explicit” is a series of scripts developed in collaboration with Ryoko Ikeda that deals with organic, abstract form and contemplates experiments that have been dealt with in aspects like geometry, light and shadows.

The intermediate goal is computationally explore shape creation, using the implementation of VBScripting that is offered inside Rhinoceros 4.0. The more far-seeing goal is to investigate algorithmic relationships among entities that usually surround us and re-establish their creative articulations, to simply allow us to deal with complexity.

This experiment, on our side, has the goal of understanding fractal object as a way to obtain morphogenesis. Each generation translates, scales and doubles. How to make it really work with rotations? The best answer would be quaternions, but also rotation matrices would do.

The construction curves are showing how the growth path resembles patterns that are typical in
nature: similar to the one that biologist observe in corals and other sea life.

Download the source code: crown.rvb.

“Option Explicit” is a series of scripts developed in collaboration with Ryoko Ikeda that deals with organic, abstract form and contemplates experiments that have been dealt with in aspects like geometry, light and shadows.

The intermediate goal is computationally explore shape creation, using the implementation of VBScripting that is offered inside Rhinoceros 4.0. The more far-seeing goal is to investigate algorithmic relationships among entities that usually surround us and re-establish their creative articulations, to simply allow us to deal with complexity.

This first experiment is inspired by microscopic pictures of rose skins. On the point of view of scripting, it uses cones replication inside a double loop.

The surfaces of those flowers take this shape becasue of their need to be porous and release fragrance. In this way, the plant can attract insects and the surface, to the naked eye, has a smooth and shadow-less appearance.

Download the source code: cones.rvb.

“Option Explicit” is a series of scripts developed in collaboration with Ryoko Ikeda that deals with organic, abstract form and contemplates experiments that have been dealt with in aspects like geometry, light and shadows.

The intermediate goal is computationally explore shape creation, using the implementation of VBScripting that is offered inside Rhinoceros 4.0. The more far-seeing goal is to investigate algorithmic relationships among entities that usually surround us and re-establish their creative articulations, to simply allow us to deal with complexity.