| ARC550 Advanced Computer Applications in Architecture Lecture Notes |
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| Friday April 19, 2002: Form·Z Rendering |
| Rendering |
| Notes
by Allen Williams: 4/19/02 Rendering times are directly related to the type of rendering engine used. Illumination. o The user has the option for the rendering engine to consider all lights as having the same intensities (“all simple”) or each light individually o By invoking the lighting analysis option, the user will be able to view the resulting lighting intensities of the lights placed in the model. Shadow options. o Shadows can be either opaque or transparent. Opaque shadows result in shadows which are rendered dark enough to block all surface styles which lie beneath them. Transparent shadows allow these features to be somewhat visible. Under rendering options, the user can invoke automatic file saving. When the rendering is completed, it will be saved when the rendering is completed. |
| Flat shading is the same as Lambert shading. The measure of the angle of incidence created by the normal and the light source results in a shade of color which is then applied to the entire face |
Gouraud shading, also known as ‘little by little’. o This type of rendering attempts to more accurately render curved surfaces Curved surfaces are faceted and color values are determined by analyzing the intersections of faces and calculates the average values of the associated normals. The result is a more accurate blending of color values which will be assigned to a model’s surfaces. |
Phong shading. Ideal for curved surfaces. o While gouraud produces an acceptable image, it still appears rather flat. Phong shading attempts to add highlights to the modeled objects. This is done by calculating the angle of reflectance, which equals the angle of incidence. § As the angle between the reflectance and incidence approaches zero degrees, the highlight intensity increases. § A full z-buffer sort is used to accomplish this. |
Ray trace. o Ray trace takes into account surface textures and color to produced a more realistic effect. o This rendering type is quite different from those mentioned so far. The rendering starts with the screen itself. Each pixel of the screen equals one ray of light. So the ray of light is traced backward from the pixels to the surface(s) it strikes, and finally back to the light source. This accounts for light reflection. |
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