Architectural Visualization: Understandings And Misunderstandings Vesselin Gueorguiev, TU- Sofia, Sofia, Bulgaria Desislava Georgieva New Bulgarian University, Sofia, Bulgaria Abstract: In the last 10 years architectural visualizations become an industry. Nevertheless many of the books available for users are oriented to the entertainment industry and only a few are oriented to the architectural visualization. The paper is oriented to 3D specialist and discuss two major points for every successful project: how architects understand CG visualization and where are visualizers and architects have misunderstanding. Keywords: Computer graphics (CG), architectural visualization, interior scene, exterior scene, lighting 1. INTRODUCTION Three-dimensional visualization has been employed extensively by architects as a medium for explaining architectural concepts since the availability of computer-aided design. It has been proved to be a far more effective communication technique compared with the conventional methods such as technical drawings and lexical documentation. However, the reason why three-dimensional visualization is better than the other techniques has not been explicitly examined. When work in area of architectural and design visualization visualizers step into a development process that is often contradictory, chaotic and conflict laden. His place in the design process comes at a critical time, often before a financial deal is made while design elements are still not defined and when ideas are just being discussed. Visualization at the early stages of a design process can stimulate thinking and bring people together. Architects preside over such discussions because of the skills they have developed to get clarity when thinking has gone fuzzy. This happens by the simple act of creating external visualizations of what has been an internal thought process. There is a concept in visualization to be remembered. Architects are looking through the rendering to the reality beyond. This is a point of misunderstanding between architects and 3D visualizers and many visualizers can t between the way things exist and they way they appear. One of most clear explanation of this was given from renowned architect and specialist in area of architectural visualizations Jeff Stikeman: We remember what a brick looks like with a mere suggestion in a more complete way than if it were photographically rendered. I don t try to put the world s most perfect brick texture on a building and render it out. I usually find that details and too much reality in one little piece tend to draw the eye and create a distraction. People remember what brick is, better than what brick looks like." As architectural design become more complex and organic in nature, engineers are left to figure out how to actually build these structures. Without visualization and high end 3D graphics many of these designs simply could not be built. The goal behind the improvement of CG is to convey ideas about a design from the designer to the client, and sometimes for the designer to better understand their designs.
This paper is oriented to explain some elements of architectural visualizations and major misunderstandings between architects and 3D visualizers points of views. 2. FILE SAVING Many architects are prepared to go the extra mile to make your clients happy, stay focused on quality, manage your clients expectations, speak their language, understand their business needs and be able to adapt and respond quickly to tight deadlines. As a result they use new techniques always with a view to what their customer will gain from them. Computer graphics technology is one of technologies that work for architects: The advancement of computer graphics technology and the development of advanced rendering software are providing major assistance to architects and designers in visualizing and analyzing their designs. Improvement of CG software provides invaluable service for most architectural and design professionals who use realistic images of the built environment, interactive animations, daylight studies and artificial lighting simulations to test design ideas within their design process. Many clients had a prejudice against computer renderings. Recently there has been an expansion of interest in visualization techniques that can be more quickly created and at the same time convey the purpose of a project to stakeholders at many levels and carry multiple meanings. Non-photorealistic (NPR) images, rather than striving for a photorealictic effect, have a communicative and expressive purpose. Research is showing that NPR images offer advantages over photographs in fields such as medicine, architecture, entertainment, education, geography and publishing. Architects are, for example designing graphics displays in operating rooms so doctors can read complex data as an image with just a glance (Fig.1) Fig. 1: Non-photorealistic visualization. Many times the idea of project is to redesign/rearrange real buildings/places. Based on real photos architects are given a location and a proposed usage. After then they rework them (fig. 2).
Fig. 2: A starting photo and architec s project. Architects wanted to find a perspective which allows a good overview of the complete building structure but at the same time providing an exciting camera angle (fig.3). But camera setup was tricky because nobody could try any position with the model itself due to memory issues. Fig. 3: Visualizations from different view points are very useful for choosing a best panorama. All time in projects architects want to have an appropriate feeling for the complex forms without hiding too much geometry in shadow regions: a sunlight system for a physically correct positioning of the sun, soft shadows and the ambient lighting are well known and frequently used characteristics of modern software for 3D realistic visualizations (fig.4). Fig. 4: Visualizations with different lighting are part of design process. Some times projects are so experimental and fantastic so the 3D tool became an architectural, structural and cultural go-between. This helps architects to reduce decision time by a considerable amount and they experiment with possibilities that they might not have considered before: they have produce end-of-phase presentation images for a more-or-less finished spaces, and in the end spent a majority of their time working on experimental variations of not-so-finished projects. 3. ARCHITECTURAL VISUALIZATION: MISUNDERSTANDING BETWEEN VISUALIZERS AND ARCHITECTS Architect has a vision, an idea, that 3D visualizer has to translate into an image. The challenge will be to get as close as possible to the architect's ideas and as close as possible to realistic image. But many times the result is far from architect s point of view. Why?
The basis of misunderstanding between architects and 3D visualizers is a fact that architecture is art but 3D visualizers are technicians. The history of architecture is synonymous with the history of the window and of daylighting from the initial crude openings, letting in light and air, heat and cold, the window was the vehicle for the introduction of daylight, and ultimately to the wondrous interiors of the many castles, churches and other buildings. As Le Corbusier said Architecture is the masterly, correct and magnificent play of masses brought together in light. Architects have used the sunlight effect in buildings to create a specific atmosphere, as for example the shafts of light entering the south side of our great cathedrals; and on a much smaller scale the use in houses of daylight and sunlight entry from above to provide necessary functional light to interior areas, where otherwise little natural light would be available. Whilst the color of daylight will vary from morning to evening, and with changes in the sky and weather patterns; it is always regarded as the reference by which color is judged, daylight is regarded as real color. The architect should take the question of view into consideration when planning his building, and when planning the location and detail of the windows. Modeling of a shape derives from its physical form, whether round, square or otherwise, coupled with the way in which light plays on its surfaces. This is referred to as its modeling and when this derives from daylight or sunlight, giving light from a single direction, this provides a form which is perceived by the eye as having meaning, unambiguous. The form of an object or space resulting from a room lit by artificial light, where the overall light may be received from a multitude of light sources. Based on architects understanding and terminology now 3D visualizers divide projects as : Interior projects: Interior design is a practice concerned with anything that is found inside a space - walls, windows, doors, finishes, textures, light, furnishings and furniture. All of these elements are used by interior designers to develop the most functional space for a building's users. Exterior projects Exterior design is a practice concerned with anything that is found outside buildings environment where the building is situated and facade of designed buildings (walls, windows and doors, wall s finishes, light, etc.). All of these elements are used by exterior designers to develop the most functional space for the users. Interior-Exterior projects This type of projects is based lighting known as semi-outdoor. The semi-outdoor is slightly different from two other types because it is a kind of interior design but the opening is bigger and divided by columns. In the beginning of all these kinds of projects every architectural visualizer should starts with one and the same question: How many kinds of light affect the scene that I am going to create and which one is the affecting scene the most?. Theoretically in these scenes every lighting effect are result of 4 types of lighting:
Skylight Skylight is the light from atmosphere, simulated by the reflectance of sunlight over the sky, cloud and everything in the atmosphere. It will influence a room with a large window or opening the most as the skylight will scatter around a large portion of the room or even throughout the entire room. So as a result, the ambient color should be a yellow-green color if walls are white or cream and the intensity of the color should be dim down. Sunlight The sunlight itself will only affect the room in some parts, that is only the floor and walls as the sun is a directional light and it will not scatter around like the skylight, with exception to its indirect illumination from floor or wall. Changing the sun angles or the sun intensity would change the final results. However, this indirect illumination will not have as much of an effect as the skylight. Indirect light Indirect light is bounced light that reflects from an object when it is affected by direct light. The color of that light is affected by the color of the object. Artificial lights With the development of artificial lighting, the illumination levels of interior environments could be more accurately controlled. As a result of influence between lights with their shape, intensity, brightness, spectrum, temperature, coherence, and simulated in 3D packages digital cameras, two major problems should be workingout: approximate color consistency and chromatic aberrations. The importance of light as an inherent part of design visualizations is due to the fact that most of the information people receive about the world comes through the eyes - light rays people perceive with the eyes carry information about the objects surrounding us. Therefore, the most common mistakes in visualizations are: wrong choice and rendering of the nature of lighting: exterior/interior; natural/artificial wrong rendering of the interaction of light with object textures wrong rendering of different natural phenomena and events Very few people realize how the system of light perception (eyes, standard camera and digital camera) influences the process of visualization of the perceived light. This is the first major weakness of most design visualizers because many peoples think that in visualizing software computer light processing as an analogue of human perception. Ever since the first steps in the area of computer visualizations, applications have rendered observation through a camera (hole camera), i.е. they have always tried to resemble the reality of a camera-shot image (there truly exists what is called a perspective point of view but it also differs from what we see through the eyes). This is why one of the most commonly found advice in books on photorealistic graphics and animation is, Choose a photograph similar to your scene, study it and try to imitate it. This is a valuable piece of advice but it often causes mistakes in the rendering of visualizations. The skill to apply it successfully is actually one of the things that differentiate professionals from amateurs. In order to understand the problems with light in visualizations based on analogies with real life scenes, we have to identify the following specifics of a scene:
Influence of objects outside the scene, i.e. the alteration of light in the scene as a result of interaction with objects not visible through the camera this includes a whole school known as Global Illumination without which modern visualizations look childish. Interaction of light with the textures of objects in the scene this is crucial to a correct rendering of the textures of different objects in the scene. Influence of the computer camera on lighting effects the main problem here being the impossibility of rendering effects with continual exposure. As a result of unsuitable lighting model in architectural visualizations can be find two wellknown mistakes: Bad shadows Architects think that visualizers do not understand the importance of shadows in their project and this misunderstanding can be explained with two sentences: o Cool light (color) warm shadow (color) and warm light cool shadow. o The different look between soft and sharp shadows makes the scene look more fuzzy and realistic. Unrealistic looking objects In many cases this problem is associated only with materials and textures. But this is a constricted outlook. Architectural visualizations are closely connected with clean materials (metal, marble, stone/ceramics elements, textile, many kinds of glass and mirrors, objects and decorations from different kinds of woods), but architect is a forms designer. The examples of this misunderstanding are: o Objects in the architects projects are oriented to people and they do not be dangerous for people which will use them. As a result objects have no sharp edges, they have only rounded edges and the amount of this round depend on potential users this is a reason why toys for little children have so rounded edges and points. o The object for architect is not only shape of outside surface - this is a collection of parts with self-dependent shape and purpose and all these parts are jointed. How these parts are joined, what are their shape and material, how they are placed all this is used from architects to give users an impression about something well known, useful and undangerous. 4. CONCLUSION Having been in architectural and design visualization industry for the last 10 years, architects/architectural visualizers have seen it come a very long way, but until recently it has not received the same level recognition that CG counterparts in the gaming and entertainment fields have received. The architectural and design visualization industry was predicted to grow 23% over the next 7 years and this is a many times bigger then the expected grow for the entertainment and gaming industries in that same timeframe. If we want to increase the success we should start to study 3D visualizers to understand architects and should start to study architects to understand software and hardware limitation for visualizers.
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