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3D –graphics and animation

Cameras and lights

Harri Airaksinen

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Camera types

Modeling systems have their default camera (perspective view). Camera can be rotate, zoom …

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Camera types

Target camera(location – target)

POV = Point of View

Free cameraCamera is located by

pointing, direction is the viewport direction

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Focal lengthFocal plane

Focal length -[live area], area, where cameras properties/controls make it possible to see 3D –objects through camera

Focal plane, plane fixed by cameras lens, where 3D environment can be seen nicely

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Seeing through camera

How to present the viewport?

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The depth of field

Lens/cameras feature, what area in 3D environment can be seen nicely

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Camera controls – 3D Studio Max

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How to use cameras?

Point of View Shots; directly to the target, many cases height of persons eyes

Low Angle and High Angle Shots

Reverse Angle Shots

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How to use cameras?

Close-Up Shots Medium and Wide Shots Long Shots / Tele Shots

[ Computer Graphics, Principles and Practice; James D. Foley, Andries van Dam, Steven K. Feiner, John F. Hughes ]

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Camera lens types

Common 3D modeling tools have wide collection of lenses (and you can build your own)

Note! Real photography light sensible film must places to projection plane

In 3D environment simulated cameras projection plane can be anywhere

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Camera lens types

• offers an adequate 46 degreeangle of view with very littleperspective distortion and withaverage depth of field -> useful for medium to wideshots.

Type Focal lenght

Fisheye 7,5 mm

Extreme Wide Angle 18 mm

Wide Angle 28 mm

Medium Wide Angle 35 mm

Standard / Normal 50 - 55 mm

Medium Long 80 mm

Long / Telephoto 135 - 250 mm

Extra Long / Super tele photo

500 mm or more

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Camera lens types

A wide angle 24 or 28 mm lens supplies a 83 degree angle of view, outstanding depth of field, but also a small amount of distortion on the edges of the picture due to the forced perspective projection typical of the wide angle of vision.

A telephoto 135 mm lens hasexcellent abilities for close framing -> flattens the perspective and has anarrow 5 degree angle of view anda small depth of field.

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Lenses in generally – link between focal length and the angle of view

Lenses with a short focal length offer a wide angle of view and increased depth of field, but objects appear distant to the camera

Lenses with a long focal length have narrow

angles of view and depth of field

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If you don’t change the lens, but camera is moving – what happen?

Camera is moving away from target: Image area is increasing The depth of field is increasing

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When both the lens and the point of view are changed ?

The subjects in the foreground of the image remain within a similar scale as long as:

the focal length decreases or increases along with the distance between the camera and the subject

The projection of the background elements

is significantly different

[The Art of 3-D Computer Animation and Imaging; Isaac Victor Kerlow]

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Camera animations

The camera has a powerful storytelling effect because it leads the eyes and mind of an audience through a story

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Camera animations and paths

Camera movement is controlled by path (line, spline or some other 2D object)

Camera POV: down the path, targeted to point of interest, changing point of interest or combination all of these

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Camera animations and paths

Select camera motion Assign Controller

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The use of camera and layout- dramatic art -

Use different cameras to tell the story and expressing the emotion

Keep the long straight lines in the composition parallel or perpendicular to the edges of the image to avoid unwanted tension and distraction -> the horizon or a tall tree in a landscape tilting to one side especially when the tree is close to an edge of the image

The camera too close to an object may result in images with large unfocused areas occupied by these objects -> effect often overwhelms the rest of the image emotion (example. face is zoomed, only eye or mouth is seen)

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The use of camera and layout- dramatic art -

It is usually distracting to cut off the head of a subject in a head shot or a portion of the object in a close-up shot -> when done skillfully, cutting off portions of the main subject can help the viewer focus on details -- such as the eyes or the mouth, for example -- that may add emotion to the image

When image clarity is an important issue, it helps to place the main subject in a shot against plain backgrounds. Backgrounds with dense textures or with a multitude of objects and colors tend to take the attention of the viewer away from the items in the foreground

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Lights and 3D environment

Point lights Spot lights Linear lights Area lights Infinite lights Ambient lights

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Point light (Omni)(an omni-directional light)

casts light evenly in all directions . Example, light bulb

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Spot light

Cast light in a cone shape and only in one specific direction Features: a variable-angle cone of light and a light fall-off

factor. Example; Flashlight

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Linear light

Linear lights have length but no width, and can also be scaled to any size – example: The light of the fluorescent tubes

[The Art of 3-D Computer Animation and Imaging; Isaac Victor Kerlow]

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Area light

Some programs provide area lights in the form of rectangular areas of light

Area lights can be scaled to almost any size but are more efficient when kept small

Area lights can also be used tosimulate the reflection of lightcoming into an interior spacethrough the open windows.

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Ambient light

The light is distributed evenly throughout the entire scene a point light source that is created automatically by the program for each scene. Some programs can simulate the sun

Simulating the sun, 3D Max

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Ambient light

Even though an ambient light source can be placed in a specific XYZ position in three-dimensional space -> an ambient light is coming from all directions

The ambient light source often determines the general level of illumination, or shade,

of a scene and almost always there is only one ambient light source per scene

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Basic Components of a Light Source

All simulated light sources include: Position ( spot lights have orientation and cone angle ) Color and intensity Decay and fall-off Glow Shadows

Lights can be edited separately. Some programs also allow to group several of these attributes and save them together in a file, called a light shader

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Lights color and intensity

Color Intensity, (how strong)

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Decay (light weaks down) and Fall-Off (shadow soft part)

The decay value of light controls the force of a light source and how far from the light source the light travels:

A weak light decays rapidly A strong light decays slowly and travels far

The light created from spot lights, decays as it moves away from the light source, but also as it moves from the center of the beam Fall-Off

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Cone angel and light beam- Glow -

The glow of a light is a circle of light that forms around the light source the light is refracted and reflected by particles in the environment, generally ice, dust, or smoke

The glow of a point light usually occurs as a circle or halo around the light source

Example. headlight

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Volume light

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Global and local lights

Global = general lights for all objects. Default light with default values

Local = added lights, targeted some objects or parts creating effects

[Computer Graphics, Principles and Practice; James D. Foley, Andries van Dam, Steven K. Feiner, John F. Hughes]

Using global light Using local light

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Shadows

All lights creates shadows You can select: use shadows or not Shadows outlook depends on shadows features,

objects features (shape, softness, transparency) and rendering algorithm

Shadows can be defined by several parameters: color of the shadow color of the penumbra softness of the shadow edge

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Shadows

3D Studio Maxremember: lightshadows on

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Lighting the Scene

Lightning is important without adequate lighting, shapes, colors, and textures can only be experienced halfway

Using computer based lighting is interesting; you have ambient light, everything else is based on your talent

Theories behind scene lighting drama to comedy different lighting

Categories of lighting are: the main action area the secondary action areas the backgrounds ambient or fill-in lighting visible light sources moving lights

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Categories of lighting

The main action area, where most of the action takes place :

A couple of spot lights might be enough for a simple shot of a mostly static scene

A several of point lights and spot lights might be needed to delineate the motion of the characters running back and forth on the stage

Note! Number of cameras. Lights can be also turned off The secondary action area, place in the scene into which

some of the action eventually spills: Most case not so many lights than the main area

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Categories of lightingbackground and lights

The background = the stage, the scenery, the surroundings : Scenery - especially backdrops with texture maps - is very

sensitive to colored light. The fill-in light = ambient light, and has the dual purpose of

defining the overall color tone of the entire scene. Created with infinite light sources and also with spot lights

Visible light sources are sources of light that can be seen by the camera and the spectators, example. lamps, fireplaces, reflectors, candlelight, televisions ..

Moving Lights; A theater stage emphasize something series of spot lights that are mounted on the camera and follow the action by trailing the camera

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Lights changes as a time function - Explosions