Business and Computing Deanery Multimedia Week 21 Materials

Multimedia 2 Last week Realtime and photorealistic Rendering Lighting concepts Types of lighting Shadows

Multimedia 3 This week - materials Why materials? Working with materials in 3ds max Shaders and rendering Surface properties Applying maps Bitmaps Procedural Libraries Exporting materials

Multimedia 4 Materials - a context… To model furniture how would you apply material to an object to model: A shinny metal chair? Wood surface on a chest of drawers? Marble vase? A glass table top? A tumbler with blackcurrant squash? To display a wooden bowl, full of oranges? A video recorder? A stone fireplace? A metal light fitting, with the light turned on

Multimedia 5 Concepts Consider modelling a brick wall Can you think of three ways to do it? Which would look best?

Multimedia 6 Using materials in 3ds max Use the library that comes with the software Make you own Apply a map Procedural Bitmap

Multimedia 7 Materials Materials are like paint With materials, you make apples red and oranges orange You put the shine in chrome and the polish on glass Materials are what make your scenes look real

Multimedia 8 Materials and light Light is reflected from the surfaces of your model Consider how the light and materials will interact Will it reflect its surroundings? Will it be bumpy or smooth? Old, clean or dirty?

Multimedia 9 Material editor Materials Defined Created Applied Sample shots Parameters Shaders Maps 3ds max v7

Multimedia 10 Material parameters Shaders Specular Diffuse Ambient colour Specularity Glossiness Opactiy or transparency

Multimedia 11 Rendering The computer “paints” the result of calculation onto the screen as an image Takes into account the geometry of the model, but also Colours Textures Light position, intensity, colour The viewport is a preview, you need to render the scene to see the materials properly

Multimedia 12 Shaders and rendering For standard materials, a shader is an algorithm that tells your software how to calculate surface rendering Each shader has a unique set of characteristics in order to serve a particular purpose

Multimedia 13 3ds types of shaders Seven shaders used with a standard material Anisotropic: For surfaces with elliptical, "anisotropic" highlights. These highlights are good for modeling hair, glass, or brushed metal. Blinn: For rounder, softer highlights than Phong shading Metal: For metallic surfaces Multi-Layer: For surfaces with more complex highlights than Anisotropic Oren-Nayar-Blinn: For matte surfaces such as fabric or terra- cotta Phong: For surfaces with strong, circular highlights Strauss: For metallic and nonmetallic surfaces. The Strauss shader has a simpler interface than other shaders. Translucent: Similar to Blinn shading, the Translucent shader also lets you specify translucency, where light is scattered as it passes through the material.

Multimedia 14 Phong Smoothes the edges between faces and renders highlights realistically for shiny, regular surfaces Interpolates intensities across a face based on the averaged face normals of adjacent faces. Calculates the normal for every pixel of the face. 3ds max v7

Multimedia 15 Blinn shading Blinn shading is a subtle variation on Phong shading The most noticeable difference is that highlights appear rounder 3ds max v7

Multimedia 16 Anisotropic highlights The Anisotropic shader creates surfaces with elliptical highlights Good for modelling hair, glass, or brushed metal 3ds max v7

Multimedia 17 Ray tracing Each pixel is calculated In 3ds max it uses mental ray renderer Generate reflections and refractions Ray tracing traces the path of rays sampled from the light source Reflections and refractions generated this way are physically accurate 3ds max v7

Multimedia 18 Surface attributes Basic material settings Colour Specular Diffuse Ambient Shininess Specularity Glossiness Transparency

Multimedia 19 Standard colour components 1. Specular The colour of shiny highlights 2. Diffuse The colour of the object in direct, "good" lighting 3. Ambient colour The colour of the object in shadow Some shaders generate the specular colour, rather than letting you choose it. 3ds max v7

Multimedia 20 Colour Hue Frequency of the light coming form the object Saturation How concentrated the colour is Value Lightness or darkness of a colour Additive colour model RGB 3ds max v7

Multimedia 21 Shininess Overall reflective nature of the object Specularity Intensity of the highlight Glossiness The size of the specular highlight Top sphere: Glossiness=100; Specular Level=100 Left sphere: Glossiness=50; Specular Level=50 Right sphere: Glossiness=0; Specular Level=0 3ds max v7

Multimedia 22 Activity Download and open up the materials fiel from the website Create 6 different materials and apply them to your spheres Polished steel, brushed aluminium, red dull plastic, red shiny plastic………….

Multimedia 23 Transparency Transparency and opacity are opposites 3ds max v7

Multimedia 24 Translucency and refraction A translucent material transmits light, but unlike a transparent material, it also scatters the light so those objects behind the material cannot be seen clearly Simulate frosted and etched glass 3ds max v7

Multimedia 25 Glow Appears to be lit from inside 3ds max v7

Multimedia 26 Activity Reopen your saved file Make a partially transparent glowing material Use the translucent shader Select self-illumination

Multimedia 27 Materials and maps Materials describe how an object reflects or transmits light Within a material, maps can simulate textures, applied designs, reflections, refractions, and other effects 3ds max v7

Multimedia 28 2D maps 2D Maps are two-dimensional images mapped onto the surface of geometric objects or used as environment maps to create a background for the scene Bitmaps can be used as 2D maps Other kinds of 2D maps are generated procedurally

Multimedia 29 Diffuse map An image is used as the diffuse colour Applied to the surface of the object Overrides the base colour Wood grain Texture of fruit Marble 3ds max v7

Multimedia 30 Procedural maps Derived from mathematical equations Simple or complex Do not degrade when you zoom into them They are 3D Marble material goes through an object as if it were solid 3ds max v7

Multimedia 31 Mapping textures Mapping is a method of projecting pictorial information onto surfaces It is a lot like wrapping a present with wrapping paper 3ds max v7

Multimedia 32 Why use bitmaps? Stick a logo on something Making street scenes or urban landscapes Use with billboard Used with avatars The map is generated by a graphic artist Use with care in real-time modelling Why?

Multimedia 33 Tiling Repetition of an image over a large area Use less memory Can look too uniform Can get join patterns 3ds max v7

Multimedia 34 Face mapping Ignores any mapping coordinates Conforms the image to the faces Select the desired face Apply the image

Multimedia 35 Bump map Bump mapping makes an object appear to have a bumpy or irregular surface Manipulates the object’s normals Does not affect the object’s mesh 3ds max v7

Multimedia 36 Mapping coordinates Use x, y z coodinates 3ds max v7

Multimedia 37 UVW co-ordinates Most material maps are a 2D plane assigned to a 3D surface. The coordinate system used to describe the placement and transformation of maps Mapping coordinates use the letters U, V, and W The three letters preceding X, Y, and Z in the alphabet.

Multimedia 38 Activity Add a procedural map to your scene Wood Marble Change the colours and grain Add a bitmap to a material in your scene

Multimedia 39 Material libraries Materials used in a model are saved in the max file The software comes with libraries of materials Create your own materials Which can then be saved to a library for use on another project Make a library from a particular scene

Multimedia 40 Special libraries Ray trace Attempts to physically model a surface instead of simulating it Form of rendering that calculates rays of light Supports advanced transparency parameters such as fog Architectural Actual physical properties Use with photometric lights to model real-life objects

Multimedia 41 Activity Use the material library to add the following: Clear glass Earth Clouds Mirror

Multimedia 42 Animated textures Use an animation or video A model of a TV May loop Think about transitions

Multimedia 43 Environments You can use an image as a background Rendering>Environment s 3ds max v7

Multimedia 44 Bitmaps for exported models Exported files do not always take colours or textures with them If you use Bitmaps you need to collect them File menu > Archive > Resource Collector

Multimedia 45 Activity Export your model as VRML Collect all the maps into a ‘maps’ folder

Multimedia 46 Self assessment You have been asked to model a prototype toy car Describe three ways of applying materials List and describe the 7 parameters of materials

Multimedia 47 For Next Week Submit your Portfolio 2.3 Work on your model

Multimedia 48 References Giambruno M, (2002) 3D Graphics & Animation, 2nd Edition, New Riders, ISBN: Kerlow I. V., (2003) The Art of 3-D Computer Animation and Effects, 3rd Edition, John Wiley & Sons Inc; ISBN: Murdock K.L., (2005) 3DS Max 7 Bible, John Wiley & Sons Inc, ISBN: Screen shots taken from 3ds max 7 User Reference