March 1, 2009Dr. Muhammed Al-Mulhem1 ICS 415 Computer Graphics Rendering Dr. Muhammed Al-Mulhem March 1, 2009 Dr. Muhammed Al-Mulhem March 1, 2009

Dr. Muhammed Al-Mulhem2 Rendering It is the process of generating an image from a model, by means of computer programs.It is the process of generating an image from a model, by means of computer programs. The model is a description of three dimensional objects in a strictly defined language or data structure.The model is a description of three dimensional objects in a strictly defined language or data structure. It would contain geometry, viewpoint, texture, lighting, and shading information.It would contain geometry, viewpoint, texture, lighting, and shading information. It is the process of generating an image from a model, by means of computer programs.It is the process of generating an image from a model, by means of computer programs. The model is a description of three dimensional objects in a strictly defined language or data structure.The model is a description of three dimensional objects in a strictly defined language or data structure. It would contain geometry, viewpoint, texture, lighting, and shading information.It would contain geometry, viewpoint, texture, lighting, and shading information.

March 1, 2009Dr. Muhammed Al-Mulhem3 Features of Rendering A rendered image can be understood in terms of a number of visible features.A rendered image can be understood in terms of a number of visible features. Rendering research and development has been largely motivated by finding ways to simulate these efficiently.Rendering research and development has been largely motivated by finding ways to simulate these efficiently. Some of these features are listed next.Some of these features are listed next. A rendered image can be understood in terms of a number of visible features.A rendered image can be understood in terms of a number of visible features. Rendering research and development has been largely motivated by finding ways to simulate these efficiently.Rendering research and development has been largely motivated by finding ways to simulate these efficiently. Some of these features are listed next.Some of these features are listed next.

March 1, 2009Dr. Muhammed Al-Mulhem4 Features of Rendering Shading — how the color and brightness of a surface varies with lighting.Shading — how the color and brightness of a surface varies with lighting. Texture-mapping — a method of applying detail to surfaces.Texture-mapping — a method of applying detail to surfaces. Shading — how the color and brightness of a surface varies with lighting.Shading — how the color and brightness of a surface varies with lighting. Texture-mapping — a method of applying detail to surfaces.Texture-mapping — a method of applying detail to surfaces.

March 1, 2009Dr. Muhammed Al-Mulhem5 Features of Rendering bump-mapping — a method of simulating small-scale bumpiness on surfaces.bump-mapping — a method of simulating small-scale bumpiness on surfaces. fogging/participating medium — how light dims when passing through non-clear atmosphere or air.fogging/participating medium — how light dims when passing through non-clear atmosphere or air. bump-mapping — a method of simulating small-scale bumpiness on surfaces.bump-mapping — a method of simulating small-scale bumpiness on surfaces. fogging/participating medium — how light dims when passing through non-clear atmosphere or air.fogging/participating medium — how light dims when passing through non-clear atmosphere or air.

March 1, 2009Dr. Muhammed Al-Mulhem6 Features of Rendering Shadows — the effect of obstructing (blocking) light.Shadows — the effect of obstructing (blocking) light. Soft shadows — varying darkness caused by partially obscured light sources.Soft shadows — varying darkness caused by partially obscured light sources. Shadows — the effect of obstructing (blocking) light.Shadows — the effect of obstructing (blocking) light. Soft shadows — varying darkness caused by partially obscured light sources.Soft shadows — varying darkness caused by partially obscured light sources.

March 1, 2009Dr. Muhammed Al-Mulhem7 Features of Rendering Reflection — mirror-like or highly glossy reflection.Reflection — mirror-like or highly glossy reflection. Transparency or Opacity — sharp transmission of light through solid objects.Transparency or Opacity — sharp transmission of light through solid objects. Reflection — mirror-like or highly glossy reflection.Reflection — mirror-like or highly glossy reflection. Transparency or Opacity — sharp transmission of light through solid objects.Transparency or Opacity — sharp transmission of light through solid objects.

March 1, 2009Dr. Muhammed Al-Mulhem8 Features of Rendering Translucency — highly scattered transmission of light through solid objects.Translucency — highly scattered transmission of light through solid objects. Refraction — bending of light associated with transparency.Refraction — bending of light associated with transparency. Translucency — highly scattered transmission of light through solid objects.Translucency — highly scattered transmission of light through solid objects. Refraction — bending of light associated with transparency.Refraction — bending of light associated with transparency.

March 1, 2009Dr. Muhammed Al-Mulhem9 Features of Rendering Diffraction — bending, spreading and interference of light passing by an object or aperture (hole or crack) that disrupts the ray.Diffraction — bending, spreading and interference of light passing by an object or aperture (hole or crack) that disrupts the ray.

March 1, 2009Dr. Muhammed Al-Mulhem10 Features of Rendering Indirect illumination — surfaces illuminated by light reflected off other surfaces, rather than. directly from a light source (also known as global illumination).Indirect illumination — surfaces illuminated by light reflected off other surfaces, rather than. directly from a light source (also known as global illumination).

March 1, 2009Dr. Muhammed Al-Mulhem11 Features of Rendering Caustics (a form of indirect illumination) — reflection of light off a shiny object, or focusing of light through a transparent object, to produce bright highlights on another object.Caustics (a form of indirect illumination) — reflection of light off a shiny object, or focusing of light through a transparent object, to produce bright highlights on another object.

March 1, 2009Dr. Muhammed Al-Mulhem12 Features of Rendering Depth of field — objects appear blurry or out of focus when too far in front of or behind the object in focus.Depth of field — objects appear blurry or out of focus when too far in front of or behind the object in focus. Motion blur — objects appear blurry due to high-speed motion, or the motion of the camera.Motion blur — objects appear blurry due to high-speed motion, or the motion of the camera. Depth of field — objects appear blurry or out of focus when too far in front of or behind the object in focus.Depth of field — objects appear blurry or out of focus when too far in front of or behind the object in focus. Motion blur — objects appear blurry due to high-speed motion, or the motion of the camera.Motion blur — objects appear blurry due to high-speed motion, or the motion of the camera.

March 1, 2009Dr. Muhammed Al-Mulhem13 Features of Rendering Photorealistic morphing —3D renderings to appear more life-like.Photorealistic morphing —3D renderings to appear more life-like. Non-photorealistic rendering — rendering of scenes in an artistic style, intended to look like a painting or drawing.Non-photorealistic rendering — rendering of scenes in an artistic style, intended to look like a painting or drawing. Photorealistic morphing —3D renderings to appear more life-like.Photorealistic morphing —3D renderings to appear more life-like. Non-photorealistic rendering — rendering of scenes in an artistic style, intended to look like a painting or drawing.Non-photorealistic rendering — rendering of scenes in an artistic style, intended to look like a painting or drawing.

March 1, 2009Dr. Muhammed Al-Mulhem14 Rendering Algorithms Global illuminationGlobal illumination Painter's algorithmPainter's algorithm RadiosityRadiosity Ray tracingRay tracing Scanline algorithms like ReyesScanline algorithms like Reyes Volume renderingVolume rendering Unbiased renderingUnbiased rendering Z-buffer algorithmsZ-buffer algorithms Global illuminationGlobal illumination Painter's algorithmPainter's algorithm RadiosityRadiosity Ray tracingRay tracing Scanline algorithms like ReyesScanline algorithms like Reyes Volume renderingVolume rendering Unbiased renderingUnbiased rendering Z-buffer algorithmsZ-buffer algorithms

March 1, 2009Dr. Muhammed Al-Mulhem15 Global illumination Global illumination is a general name for a group of algorithms used in 3D computer graphics that are meant to add more realistic lighting to 3D scenes.Global illumination is a general name for a group of algorithms used in 3D computer graphics that are meant to add more realistic lighting to 3D scenes. Such algorithms take into account not only the light which comes directly from a light source (direct illumination), but also subsequent cases in which light rays from the same source are reflected by other surfaces in the scene (indirect illumination).Such algorithms take into account not only the light which comes directly from a light source (direct illumination), but also subsequent cases in which light rays from the same source are reflected by other surfaces in the scene (indirect illumination). Global illumination is a general name for a group of algorithms used in 3D computer graphics that are meant to add more realistic lighting to 3D scenes.Global illumination is a general name for a group of algorithms used in 3D computer graphics that are meant to add more realistic lighting to 3D scenes. Such algorithms take into account not only the light which comes directly from a light source (direct illumination), but also subsequent cases in which light rays from the same source are reflected by other surfaces in the scene (indirect illumination).Such algorithms take into account not only the light which comes directly from a light source (direct illumination), but also subsequent cases in which light rays from the same source are reflected by other surfaces in the scene (indirect illumination).

March 1, 2009Dr. Muhammed Al-Mulhem16 Global illumination Theoretically reflections, refractions, and shadows are all examples of global illumination, because when simulating them, one object affects the rendering of another object (as opposed to an object being affected only by a direct light).Theoretically reflections, refractions, and shadows are all examples of global illumination, because when simulating them, one object affects the rendering of another object (as opposed to an object being affected only by a direct light). In practice, however, only the simulation of diffuse inter-reflection or caustics is called global illumination.In practice, however, only the simulation of diffuse inter-reflection or caustics is called global illumination. Theoretically reflections, refractions, and shadows are all examples of global illumination, because when simulating them, one object affects the rendering of another object (as opposed to an object being affected only by a direct light).Theoretically reflections, refractions, and shadows are all examples of global illumination, because when simulating them, one object affects the rendering of another object (as opposed to an object being affected only by a direct light). In practice, however, only the simulation of diffuse inter-reflection or caustics is called global illumination.In practice, however, only the simulation of diffuse inter-reflection or caustics is called global illumination.

March 1, 2009Dr. Muhammed Al-Mulhem17 Global illumination Images rendered using global illumination algorithms often appear more photorealistic than images rendered using only direct illumination algorithms.Images rendered using global illumination algorithms often appear more photorealistic than images rendered using only direct illumination algorithms. However, such images are computationally more expensive and consequently much slower to generate.However, such images are computationally more expensive and consequently much slower to generate. Images rendered using global illumination algorithms often appear more photorealistic than images rendered using only direct illumination algorithms.Images rendered using global illumination algorithms often appear more photorealistic than images rendered using only direct illumination algorithms. However, such images are computationally more expensive and consequently much slower to generate.However, such images are computationally more expensive and consequently much slower to generate.

March 1, 2009Dr. Muhammed Al-Mulhem18 Global illumination Examples of algorithms used in global illumination:Examples of algorithms used in global illumination: –Radiosity –Ray tracing –Beam tracing –Cone tracing, path tracing –Metropolis light transport –Ambient occlusion –Photon mapping –Image based lighting Examples of algorithms used in global illumination:Examples of algorithms used in global illumination: –Radiosity –Ray tracing –Beam tracing –Cone tracing, path tracing –Metropolis light transport –Ambient occlusion –Photon mapping –Image based lighting

March 1, 2009Dr. Muhammed Al-Mulhem19 Example-Global illumination Rendering without Global Illumination.Rendering without Global Illumination. –Consider the next Figure. –Note that we are looking at a fully-enclosed scene through a one-way-transparency scheme (see the chrome sphere's reflection of the otherwise invisible white and green walls). –There is a lack of definition in areas that are outside the beam of direct light from the ceiling lamp. –For example, the geometry of the ceiling lamp's housing is obscured within a solid grey area produced by an ambient color. –Without the ambient color added into the rendering equation, this surface would be black. Rendering without Global Illumination.Rendering without Global Illumination. –Consider the next Figure. –Note that we are looking at a fully-enclosed scene through a one-way-transparency scheme (see the chrome sphere's reflection of the otherwise invisible white and green walls). –There is a lack of definition in areas that are outside the beam of direct light from the ceiling lamp. –For example, the geometry of the ceiling lamp's housing is obscured within a solid grey area produced by an ambient color. –Without the ambient color added into the rendering equation, this surface would be black.

March 1, 2009Dr. Muhammed Al-Mulhem20 Example-Global illumination

March 1, 2009Dr. Muhammed Al-Mulhem21 Example-Global illumination Rendering with global illuminationRendering with global illumination Note how light is reflected by surfaces.Note how light is reflected by surfaces. Note how colors transfer (or "bleed") from one surface to another, an effect of diffuse inter-reflection.Note how colors transfer (or "bleed") from one surface to another, an effect of diffuse inter-reflection. Notice how colors from the red and green walls are diffusely reflected by other surfaces in the scene (one-way transparency is used to allow us to see "through" two walls from the outside while preserving their effect inside the scene).Notice how colors from the red and green walls are diffusely reflected by other surfaces in the scene (one-way transparency is used to allow us to see "through" two walls from the outside while preserving their effect inside the scene). Also notable is the caustic projected on the red wall as light passes through the glass sphere.Also notable is the caustic projected on the red wall as light passes through the glass sphere. Rendering with global illuminationRendering with global illumination Note how light is reflected by surfaces.Note how light is reflected by surfaces. Note how colors transfer (or "bleed") from one surface to another, an effect of diffuse inter-reflection.Note how colors transfer (or "bleed") from one surface to another, an effect of diffuse inter-reflection. Notice how colors from the red and green walls are diffusely reflected by other surfaces in the scene (one-way transparency is used to allow us to see "through" two walls from the outside while preserving their effect inside the scene).Notice how colors from the red and green walls are diffusely reflected by other surfaces in the scene (one-way transparency is used to allow us to see "through" two walls from the outside while preserving their effect inside the scene). Also notable is the caustic projected on the red wall as light passes through the glass sphere.Also notable is the caustic projected on the red wall as light passes through the glass sphere.

March 1, 2009Dr. Muhammed Al-Mulhem22 Example-Global illumination

March 1, 2009Dr. Muhammed Al-Mulhem23 Demo-Global illumination Vedio

March 1, 2009Dr. Muhammed Al-Mulhem24 Radiosity Radiosity is a global illumination method.Radiosity is a global illumination method. Direct Illumination is a term that covers the principal lighting methods used by old school rendering engines such as 3D Studio and POV.Direct Illumination is a term that covers the principal lighting methods used by old school rendering engines such as 3D Studio and POV. A scene consists of two types of entity: Objects and Lights.A scene consists of two types of entity: Objects and Lights. Lights cast light onto Objects, unless there is another Object in the way, in which case a shadow is left behind.Lights cast light onto Objects, unless there is another Object in the way, in which case a shadow is left behind. Examples of Direct illumination techniques are:Examples of Direct illumination techniques are: –Shadow Volumes, –Z-Buffer methods, –Ray Tracing. Radiosity is a global illumination method.Radiosity is a global illumination method. Direct Illumination is a term that covers the principal lighting methods used by old school rendering engines such as 3D Studio and POV.Direct Illumination is a term that covers the principal lighting methods used by old school rendering engines such as 3D Studio and POV. A scene consists of two types of entity: Objects and Lights.A scene consists of two types of entity: Objects and Lights. Lights cast light onto Objects, unless there is another Object in the way, in which case a shadow is left behind.Lights cast light onto Objects, unless there is another Object in the way, in which case a shadow is left behind. Examples of Direct illumination techniques are:Examples of Direct illumination techniques are: –Shadow Volumes, –Z-Buffer methods, –Ray Tracing.

March 1, 2009Dr. Muhammed Al-Mulhem25 Radiosity methods try to overcome some of the problems associated withGlobal illumination methods try to overcome some of the problems associated with Direct Illumination. While a tends to simulate light reflecting only once off each diffuse surface, renderers simulate very many reflections of light around a scene.While a Direct Illumination tends to simulate light reflecting only once off each diffuse surface, global illumination renderers simulate very many reflections of light around a scene. While each object in a scene must be lit by some light source for it to be visible, an object in a scene may be lit simply by it's surroundings.While each object in a Directly Illuminated scene must be lit by some light source for it to be visible, an object in a Globally Illuminated scene may be lit simply by it's surroundings. methods try to overcome some of the problems associated withGlobal illumination methods try to overcome some of the problems associated with Direct Illumination. While a tends to simulate light reflecting only once off each diffuse surface, renderers simulate very many reflections of light around a scene.While a Direct Illumination tends to simulate light reflecting only once off each diffuse surface, global illumination renderers simulate very many reflections of light around a scene. While each object in a scene must be lit by some light source for it to be visible, an object in a scene may be lit simply by it's surroundings.While each object in a Directly Illuminated scene must be lit by some light source for it to be visible, an object in a Globally Illuminated scene may be lit simply by it's surroundings.

March 1, 2009Dr. Muhammed Al-Mulhem26 Example - Direct Illumination Lighting a simple scene with Direct Illumination:Lighting a simple scene with Direct Illumination: A simple scene is modeled in 3D Studio.A simple scene is modeled in 3D Studio. We wanted the room to look as if it was lit by the sun shining in through the window.We wanted the room to look as if it was lit by the sun shining in through the window. So, we set up a spotlight to shine in.So, we set up a spotlight to shine in. When we rendered it, the entire room was black, except for a couple of patches on the floor that the light reached.When we rendered it, the entire room was black, except for a couple of patches on the floor that the light reached. Lighting a simple scene with Direct Illumination:Lighting a simple scene with Direct Illumination: A simple scene is modeled in 3D Studio.A simple scene is modeled in 3D Studio. We wanted the room to look as if it was lit by the sun shining in through the window.We wanted the room to look as if it was lit by the sun shining in through the window. So, we set up a spotlight to shine in.So, we set up a spotlight to shine in. When we rendered it, the entire room was black, except for a couple of patches on the floor that the light reached.When we rendered it, the entire room was black, except for a couple of patches on the floor that the light reached.

March 1, 2009Dr. Muhammed Al-Mulhem27 Example - Direct Illumination Turning up the Ambient Light simply caused the room to appear a uniform grey, except for the uniformly red floor, and light patches. Lastly, we turned the background color to white, to give the appearance of a bright sky. Turning up the Ambient Light simply caused the room to appear a uniform grey, except for the uniformly red floor, and light patches. Lastly, we turned the background color to white, to give the appearance of a bright sky.

March 1, 2009Dr. Muhammed Al-Mulhem28 Example - Direct Illumination

March 1, 2009Dr. Muhammed Al-Mulhem29 Example - Global Lighting Lighting a simple scene with Global Lighting: We modeled the same scene by radiosity renderer.We modeled the same scene by radiosity renderer. To provide the source of light, we rendered an image of the sky with Terragen (scenery generator), and placed it outside the window.To provide the source of light, we rendered an image of the sky with Terragen (scenery generator), and placed it outside the window. No other source of light was used.No other source of light was used. With no further effort, the room looks realistically lit.With no further effort, the room looks realistically lit. Lighting a simple scene with Global Lighting: We modeled the same scene by radiosity renderer.We modeled the same scene by radiosity renderer. To provide the source of light, we rendered an image of the sky with Terragen (scenery generator), and placed it outside the window.To provide the source of light, we rendered an image of the sky with Terragen (scenery generator), and placed it outside the window. No other source of light was used.No other source of light was used. With no further effort, the room looks realistically lit.With no further effort, the room looks realistically lit.

March 1, 2009Dr. Muhammed Al-Mulhem30 Example - Global Lighting

March 1, 2009Dr. Muhammed Al-Mulhem31 Example - Global Lighting Interesting points to note: The entire room is lit and visible, even those surfaces facing away from the sun. Soft shadows. The change in brightness across the wall to the left of the scene. The grey walls, have a certain red color to them. The ceiling is slightly pink. Interesting points to note: The entire room is lit and visible, even those surfaces facing away from the sun. Soft shadows. The change in brightness across the wall to the left of the scene. The grey walls, have a certain red color to them. The ceiling is slightly pink.

March 1, 2009Dr. Muhammed Al-Mulhem32 The Workings of a Radiosity Renderer The basic premise of Radiosity. Any light that hits a surface is reflected back into the scene. That's any light. Not just light that's come directly from light sources. Anything that is visible is either emitting or reflecting light, i.e. it is a source of light. The basic premise of Radiosity. Any light that hits a surface is reflected back into the scene. That's any light. Not just light that's come directly from light sources. Anything that is visible is either emitting or reflecting light, i.e. it is a source of light.

March 1, 2009Dr. Muhammed Al-Mulhem33 The Workings of a Radiosity Renderer Everything you can see around you is a light source. And so, when we are considering how much light is reaching any part of a scene, we must take care to add up light from all possible light sources. Basic Premises: There is no difference between light sources and objects. A surface in the scene is lit by all parts of the scene that are visible to it. Everything you can see around you is a light source. And so, when we are considering how much light is reaching any part of a scene, we must take care to add up light from all possible light sources. Basic Premises: There is no difference between light sources and objects. A surface in the scene is lit by all parts of the scene that are visible to it.

March 1, 2009Dr. Muhammed Al-Mulhem34 The process of performing Radiosity on a scene A Simple Scene We begin with a simple scene: a room with three windows. There are a couple of pillars and some alcoves, to provide interesting shadows. It will be lit by the scenery outside the windows, which we will assume is completely dark, except for a small, bright sun. A Simple Scene We begin with a simple scene: a room with three windows. There are a couple of pillars and some alcoves, to provide interesting shadows. It will be lit by the scenery outside the windows, which we will assume is completely dark, except for a small, bright sun.

March 1, 2009Dr. Muhammed Al-Mulhem35 The process of performing Radiosity on a scene Now, lets choose one of the surfaces in the room, and consider the lighting on it.

March 1, 2009Dr. Muhammed Al-Mulhem36 The process of performing Radiosity on a scene As with many difficult problems in computer graphics, we'll divide it up into little patches, and try to see the world from their point of view.

March 1, 2009Dr. Muhammed Al-Mulhem37 The process of performing Radiosity on a scene Take one of those patches. And imagine you are that patch.Take one of those patches. And imagine you are that patch. What does the world look like from that perspective?What does the world look like from that perspective? Take one of those patches. And imagine you are that patch.Take one of those patches. And imagine you are that patch. What does the world look like from that perspective?What does the world look like from that perspective?

March 1, 2009Dr. Muhammed Al-Mulhem38 The process of performing Radiosity on a scene View from a patch: This patch can see no light. The room is very dark, the edges are drawn for demonstration. By adding together all the light it sees, we can calculate the total amount of light from the scene reaching the patch. We'll refer to this as the total incident light from now on. This patch can only see the room and the darkness outside. Adding up the incident light, we would see that no light is arriving here. This patch is darkly lit. View from a patch: This patch can see no light. The room is very dark, the edges are drawn for demonstration. By adding together all the light it sees, we can calculate the total amount of light from the scene reaching the patch. We'll refer to this as the total incident light from now on. This patch can only see the room and the darkness outside. Adding up the incident light, we would see that no light is arriving here. This patch is darkly lit.

March 1, 2009Dr. Muhammed Al-Mulhem39 The process of performing Radiosity on a scene View from a lower patch Pick a patch a little further down the pillar. This patch can see the bright sun outside the window. This time, adding up the incident light will show that a lot of light is arriving here. This patch is brightly lit. View from a lower patch Pick a patch a little further down the pillar. This patch can see the bright sun outside the window. This time, adding up the incident light will show that a lot of light is arriving here. This patch is brightly lit.

March 1, 2009Dr. Muhammed Al-Mulhem40 The process of performing Radiosity on a scene Lighting on the Pillar Having repeated this process for all the patches, and added up the incident light each time, we can look back at the pillar and see what the lighting is like. The patches nearer the top of the pillar, which could not see the sun, are in shadow, and those that can are brightly lit. Shadows naturally appear in parts of the scene that cannot see a source of light. Lighting on the Pillar Having repeated this process for all the patches, and added up the incident light each time, we can look back at the pillar and see what the lighting is like. The patches nearer the top of the pillar, which could not see the sun, are in shadow, and those that can are brightly lit. Shadows naturally appear in parts of the scene that cannot see a source of light.

March 1, 2009Dr. Muhammed Al-Mulhem41 The process of performing Radiosity on a scene

March 1, 2009Dr. Muhammed Al-Mulhem42 The process of performing Radiosity on a scene Entire Room Lit: 1st Pass Repeating the process for every patch in the room, gives us this scene. – –Everything is completely dark, except for surfaces that have received light from the sun. What's important to notice is that the room is completely dark, except for those areas that can see the sun. At the moment it's no improvement over any other renderer. Well, it doesn't end here. Now that some parts of the room are brightly lit, they have become sources of light themselves, and could well cast light onto other parts of the scene. Entire Room Lit: 1st Pass Repeating the process for every patch in the room, gives us this scene. – –Everything is completely dark, except for surfaces that have received light from the sun. What's important to notice is that the room is completely dark, except for those areas that can see the sun. At the moment it's no improvement over any other renderer. Well, it doesn't end here. Now that some parts of the room are brightly lit, they have become sources of light themselves, and could well cast light onto other parts of the scene.

March 1, 2009Dr. Muhammed Al-Mulhem43 The process of performing Radiosity on a scene

March 1, 2009Dr. Muhammed Al-Mulhem44 The process of performing Radiosity on a scene View from the patch after 1st Pass Patches that could not see the sun, and so received no light, can now see the light shining on other surfaces. So in the next pass, this patch will come out slightly lighter than the completely black it is now. View from the patch after 1st Pass Patches that could not see the sun, and so received no light, can now see the light shining on other surfaces. So in the next pass, this patch will come out slightly lighter than the completely black it is now.

March 1, 2009Dr. Muhammed Al-Mulhem45 The process of performing Radiosity on a scene Entire Room Lit: 2nd Pass This time, when you calculate the incident light on each patch in the scene, many patches that were black before are now lit. The room is beginning to take on a more realistic appearance. What's happened is that sun light has reflected once from the floor and walls, onto other surfaces. Entire Room Lit: 2nd Pass This time, when you calculate the incident light on each patch in the scene, many patches that were black before are now lit. The room is beginning to take on a more realistic appearance. What's happened is that sun light has reflected once from the floor and walls, onto other surfaces.

March 1, 2009Dr. Muhammed Al-Mulhem46 The process of performing Radiosity on a scene Entire Room Lit: 3rd Pass The third pass produces the effect of light having reflected twice in the scene. Everything looks pretty much the same, but is slightly brighter. Entire Room Lit: 3rd Pass The third pass produces the effect of light having reflected twice in the scene. Everything looks pretty much the same, but is slightly brighter.

March 1, 2009Dr. Muhammed Al-Mulhem47 The process of performing Radiosity on a scene The next pass only looks a little brighter than the last, and even the 16 th is not a lot different. There's not much point in doing any more passes after that.The next pass only looks a little brighter than the last, and even the 16 th is not a lot different. There's not much point in doing any more passes after that. The radiosity process slowly converges on a solution. Each pass is a little less different than the last, until eventually it becomes stable. Depending on the complexity of the scene, and the lightness of the surfaces, it may take a few, or a few thousand passes. It's really up to you when to stop it, and call it done.The radiosity process slowly converges on a solution. Each pass is a little less different than the last, until eventually it becomes stable. Depending on the complexity of the scene, and the lightness of the surfaces, it may take a few, or a few thousand passes. It's really up to you when to stop it, and call it done. The next pass only looks a little brighter than the last, and even the 16 th is not a lot different. There's not much point in doing any more passes after that.The next pass only looks a little brighter than the last, and even the 16 th is not a lot different. There's not much point in doing any more passes after that. The radiosity process slowly converges on a solution. Each pass is a little less different than the last, until eventually it becomes stable. Depending on the complexity of the scene, and the lightness of the surfaces, it may take a few, or a few thousand passes. It's really up to you when to stop it, and call it done.The radiosity process slowly converges on a solution. Each pass is a little less different than the last, until eventually it becomes stable. Depending on the complexity of the scene, and the lightness of the surfaces, it may take a few, or a few thousand passes. It's really up to you when to stop it, and call it done.

March 1, 2009Dr. Muhammed Al-Mulhem48 The process of performing Radiosity on a scene 4 th 16 th