Hello,
This is a short Overview over my diploma thesis “Sketching in Space: concept and design of hybride tools to sketch in threedimensional virtual environments”. The text below was originally conceived as a paper. It is co-written with Dipl. Inform. Johann Habakuk Israel, who was very helpful while the whole process of writing, designing and thinking about hybrid design scenarios. Next to him I have to mention Dr. Jörg Petruschat for constantly flashing inspirations and theoretical backgrounds. Thanks a lot.
please let me mention that this is not a scientific article. There will be no sources mentioned. Please check out the whole work as PDF for further information like related sketches, mock ups, theories to VR, spatial perception and design problem solving. Aswell there is a more detailed description of the related hardware and the interaction within the CAVE systems
(sorry…but only in german).
Abstract
Sketching is an essential activity in the creative work of designers. Sketching can be described as a process of self-reflecting in which the designer is externalizing her ideas and generating new solution variants.
Virtual Reality (VR) Technology provides means for designers to sketch, that means to think, directly in three-dimensional space. This may support the ideation, because it allows to externalize spatial ideas directly into virtual space and to “walk” within the sketch.
We present working tangible tools for immersive three-dimensional sketching: a hybrid physical/virtual pen, an entirely physical pen, a Bezier tool, an extrusion tool called shaper and a history slider. We also present results from a 3D sketching study which show that designers tend to create three dimensional drawings even if requested to sketch flat on virtual 2D planes. We argue that three-dimensional sketching is a new expressive and promising form of externalizing ideas, and that it might significantly facilitate the ideation phase in industrial design. The environment the sketching takes place in is a CAVE and the tracking technology is magnetic, whi has the advantage, that there are no strange antennas attached on the tools.
The results of this work have been evaluated in focusgroups, which are not to be published until now. Stay tuned for further informations.
Introduction
Sketches are usually the first visual product models that designers create by externalizing their mental models and concepts of the product . But, as Suwa & Tversky point out, sketching is not only about externalizing pre-existing mental models. Designers rather develop their ideas while sketching and discover new links and approaches for new product features (reflecting-in-action )
During the product creation process, sketches are essential means in the product planning and task clarification phase (finding and choosing product ideas), the conceptual phase (concretizing of principle solution variants) and the embodiment design phase (preliminary design, choosing proper variants, detail design). Sketching on paper is still the most prominent form of sketching: 60 percent of all drawings made during product design are sketches, 80 percent of the time spent for writing or tracing solutions is used for creating sketches and the ratio of creation time compared to utilization is much higher for sketches (3:1) than for technical drawings (1:1). Sketches are particularly often being made when using CAD Systems. The core properties of sketches as per Buxton are, that they are quick and timely to create, inexpensive, disposable, plentiful (you can create hundreds), sketches have a clear vocabulary, minimal detail, and are ambiguous, they suggest and explore solutions rather than confirm. Sketches must not necessarily be pen and paper drawings but can also made up of collages or physical models . That physical means still supercede computers as sketching tools is usually ascribed to the delay and low resolution of the digital systems which slow down the self-communication process and hinder designers to simultaneously draw concurrently and think [Römer].
If virtual environments are a new medium and as such very likely to influence the sketching process and sketches are a reflective means which do not only represent but also generates knowledge about a product, then three-dimensional sketching should significantly alter the sketching process. Among other reasons, we expected 3d sketching to be more appropriate for externalizing visual mental models because of their three dimensional nature, allowing designers to move within their drawing and providing more cues for the self-communication process.
The hybrid tools for spatial sketching
Virtual Space is a new media and creates new possibilties to generate and express new ideas, concepts, thoughts and informations. To reach this goal, the interactionfacilities, e.g. the sketchingtools have to be designed in a way, that allows an intuitive and barrierfree interaction. There should not be the feeling of a complicated device between the designer and the sketch.
It is not enough to only transfer the allready existing real 2D Sketchingtools into a 3D virtual Environment, because it has it´s own special rules and offers completely new possibilities in graphic expression. New concepts and tools have to be found, that allow a type of interaction, in which the user can use his/her whole motorics kills to create free and passionate sketches but also aimfull problem solving graphics.We developed three main hybrid tools, that we will present and explain in particular. hybrid tools, because they create virtual shape, but there body is real, and graspable like a real tool. Their handling should enable the user to create intuitively virtual shapes, strokes and solutionfinding sketches without the feeling of being in an artificial environment.
The Pen tool
The pen is the basic tool. It offers the possibility to draw simple strokes in to “the air” that vary in width depending on the pressure the user applies on the pen. By this the user can lay more expression and a personal aspect into the sketch. The pen is designed, that it works without buttons, because sketching is in reality also buttonfree. To activate the pen, the upper lighter part has to be pressed slightly against the lower part. That reffers to the habit of putting the pen on the paper. This tactile feedback is important, because, it let the hand feel that it is sketching and creates the imagination of using a graspable medium.
Depending on the way to hold the pen, the sketching person can make filigree and detailed sketches or wide and very spatial drawings. By holding the pen like a pencil, the hand moves out of the wrist, that enables the sketching person to draw in a less wide surround, but very fine and detailed. Holding the pen like a big painterbrush, leads to a handmovement out of the shoulder. The resulting shapes are, related to the movemant of the arm, wider, and less detailed.
The lower part of the pen has a mould on both sides, that provide an ergonomic handling an let the person intuitivly hold the pen in the ‘”right way”. Also there is a bump, in which the forcesensor is integrated and the upper part is pressed against. The magnetic tracking device is while prototype phase added at the end of the pen, but should be integrated in further states.
Despite the wish of some designers of integrating an eraserfunction, we did not integrated it. From our point of view, erasing is opposite to the charachter of the sketch. Every stroke is determined by it´s previous one. When a sketch helps to solve problems by visualise thoughts and corrigate and oversketch them, the eraser would let the Designer tend to make his mistakes again and again.
The Bezier tool
Another sketching tool we developed are the “Bezierhandles”. They relate to the representation of the bezieralghorythms in CAD software, used by designers and engineers. This pair of tools enables the Designers to create threedimensional cubic beziercurves in the virtual environment by hand. This means without typing numeric parameters or wimp systems. Further, these curves can be extruded to Bezierplanes with the same tools.
The design of the tool is similiar to the pen tool. The difference is, that the Bezierhandles are meant to be used as a pair and that the body is more vouluminous, because it has to be grasped with the whole hand. Again the upper part has to be slightly pressed against the lower one, either on the right- or left hand, so that a virtual curve spans between the two handles. According to the motion of the handles and the resulting position the curve curvature in shape and length. Is the designer content with the result, he can let loose the pressed handle and the curve floats “in the air”. Does he pushes the other handle instead of letting loose the already pressed one, he can exrude the curve to a plane by moving the handles to the wished position.
It´s not possible to change the lenght of the vectors P0 - P1 and P2 - P3. They are fixed. But the length and curvature of P1 - P2 can be varied by moving the handles around.
SHAPER
The shaper enables the user to create new virtual tools in the virtual environment. Conceptually it was difficult to integrate all useful types of sketching utilities, because there would be too many. So we decided to let the user sketch the tools they want to use, easily by hand via another hybrid sketchingdevice, which would bring a whole new quality in ideation and translation of ideation, when there is no limiting set of tools. So we developed a tool, which actually is just a handhold and called it “the shaper”. The user presses the grip, accordingly to the other tools and a virtual plane pops out of the top end. Depending on constancy and pressure, the size of this plane is either wide or small. This plane is like a sketchpad, whereon it is possible to draw twodimensional shapes with the pen tool. These shapes “stick” to the virtual plane and can be extruded to threedimensional shapes by pressing the grip again.
Does the user sketch a circle on the virtual plane which is more a help to draw nearly planar, he can extrude that circle to a tube with a diameter of the circle. The tube ends by letting loose the grip. The shape of the tube depends on the movement of the arm and the hand. There are plenty possible shapes to be extruded out of one simple circle. If the user draws a rectangle instead of a circle he or her can extrude it to an edged profile, which conceptuelly links the sketching process with early phases of the construction process. In a less on construction focussed way, there is also the possibilty to just sketch a single stroke on the shaper , which can be used as a brush. This part of our concept turns out the most exciting and challenging side of using virtuality. It only works in virtual environments and can be good alternative to tool-libraries and Wimp systems, because the user is not limited in choosing a tool. He can create and modify the tool by his own imagination, which may lead to a more satisfying result.
History Slider
In the focus group, the asked designers and professionals demanded something that offers the possibility of stepping back in the sketch and recover certain phases of the spatial sketch. For example they wanted to go back to the point when a certain plane, or stroke was drawn. It may remind on the protocoll function in graphical CAD Software such as Photoshop or Illustrator, where it is allready integrated to go back to certain tasks. But a sketch is allready a protocoll of thoughts that make an evolution of an idea visible and this recovery function would get near the concept of an eraser. But the “timeslider” provides another exciting effect. To “rewind” the sketch can be very inspiring and to see how you made a stroke or a plane from a distant view can have a lerning result next to the just magical impression of a stroke winding through space.
But not only in the end of a sketching process the timeslider can be used. Next to this reviewfuntion it can visualize functionality of dynamic parts of the sketch. Folding processes can be drawn and later animated with the timeslider.
Is the Timeslider, which is a faderdevice, on the most left position, the sketch is on its origion and the virtual space is empty. Moving the fader to the right makes the sketch visible, with it´s early strokes. On the most right side is the end of the sketch. If the user ovsketches strokes in the middle of the reviewed sketch, the rest is deleted, and the sketchingprocess goes further on from this point.
