3d introductorytexturingpart 5/14

8/4/2019 3D IntroductoryTexturingPart 5/14

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3D IntroductoryTexturing

Part 5+6/14

A series of lectures created for students at candidate level at the IT-University of Copenhagen by Rickard Stampe Sderstrm 2011. [email protected]. All material in this lecture is copyrighted to the autorsand creators of the pictures and films. And the lecture is copyrighted to Rickard Stampe Sderstrm. You may freely use it as a presentation but not printing it in a digital or analog form.


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What is texturing?

- The process of adding color and surface details to the 3D model with the help of shaders / materials. A shader in Maya is assigned to the model. It is it current"material". And it has numerous attributes you can adjust: color, transparency,reflections, etc.


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Shaders

- A shader contains diffrent material attributes (such as color, diffuse transparencyetc). The specular attribute is the one that vary the most for each shader.


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What is a texture?

- A texture is an image mapped on a 3D model - a technique called texture mapping.


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What is the difference?

Lambertgrey

BlinnShading

Blinn Shadingwith textures


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Shading attributes and light attributes.

- Here is a small portion of shading attributes.


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What is color?- Colors in real live are energy.

- In the render process in CG thecolors are calculated - what is called diffusion.

- In real life the light ray are reflected from thelight source on the materials to our eyes - CGuse the reverse process of that.


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How the color is rendered- The shader on the model is lit by digital lights. The models color has is the models

local color (the shading in neutral lighting) combined with the lights in the scene. Thesynthetic camera capture the color of the object that is the combination of theshaders attribute and the lighting of the scene.


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Color trough times- The process of capturing light with a camera was first used around 1820s

- Before that depicting something ment basically painting it with color pigment(acrylics, crayons etc) .

- The system of mixing colors with pigment in this traditional way is called thesubtractive color mixing.


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Color in CG- But the computer has a completly different way of handling colors - it is handling

light in the so called additative color system.

- The computer uses RGB (red, green, blue) color space, developed from the theoryof three color seeing developed by Thomas Young , Hermann Helmholtz and JamesClerk Maxwell in the middle of 19th century.

A good rule of thumb: All colors ADDINGtogether becomes white.Thats additative color system.


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- Primary colors - Secondary colors - Complementary colors


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Mixing with: HUE SATURATION VALUE

HSV modelHSV Model

HSV GUI


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Saturation

Values

Hue / Color


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Harmony in colors- Color theory from the Bauhaus theorist Johannes Ittens applied to CG.

- This theory is rooted in the subtractive old system but is as usefull in the modernadditative system. The color circle shows the primary, secondary and the tertiarycolors. Harmony is to maximaising or neutralizing the intesity of colors by combiningthem.


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Harmony in hue- What red is more RED?


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Harmony in hue- What red is more RED?

More intense


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Harmony with value- What red is more RED?


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Harmony with value- What red is more RED?

More intense


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Harmony with color tempeture- Which green green bar is the closest to you and which one is farther away.


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Harmony with color tempeture- Which green green bar is the closest to you and which one is farther away.

A warm surrounding color pushes the green out from the screen and a cold blue pushes it back.


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Harmony with color schemes- Pick colors with help of a color scheme


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Harmony with color schemes- A complementary color scheme used in a more practical sense.


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Harmony with tempeture- Combine cold and warm colors.


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Harmony with tempeture- Combine cold and warm colors.

Still picture from shorfilm Geri's Game (1997) by Jan Pinikava


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Shader attributes- Analyse the real thing.

- Ask yourself, what is it made of?- What is producing the color?


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Shader attributes- What "color" are theese?


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Shader attributes- They are blue with a shininess to them visible on the highlights.


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Shader attributes- What "color" is this?


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Shader attributes- It's not a color at all it is a reflection.


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Shader attributes- What "color" is this?


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Shader attributes- They are in different shades of green with a pattern to it. They are redish on the top edges and they aretransparent.


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Shader attributes in Maya- The most common shader attributes of the shaders

Color / Diffuse

Ambient Color

Transparency

Specular roll off

Eccentricity

Specular color

Reflectivity

Reflectivity mapping

Bump mapping

The most common type of shaders with anarray of different shader attributes:


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Shader attributes in Maya- The special attributes of the shaders

Translucence / Translucence Depth / Translucencefocus

Refractions

Subsurface Scattering

Incandescence / Glow


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Texture mapping- The process of connecting the color information from a image to a shading attribute. Wrapping a texture onthe color attribute produces a color mapping.


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Color mapping with a UV-Map- Here is a UV-map, automatically unwrapped in Maya and painted in Photoshop.- U and V is describing the 2D coordinate system.


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Unwrapping manually- Here is a UV-map manually "unwrapped". The model to the left represent the form in 3D and the UV-map onthe right is the flat form in 2D-space. By painting on the indicated areas on the UV-map you paint a texture for the color attribute etc. The process of manual UV-unwrapping is used if you don't have a 3D paint programbecause you can better interpret the UV-map when it is done manually (what part you are painting on)compared to an automatic unwrap as in the previous slide.

Rules of thumb:No UV coordinate can share the same space in the 2D coordinate.Evenly distribute the UV-coordinates of the model with as few seems as

possible on the UV-map. Picture: Unknown.


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Opacity mapping- Here is the transparency of the shader textur mapped. But generally every shading attribute can be texturemapped.

TextureTexture mappedtransparency


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Bump / Normal / Displacement mapping

- Using textures to add structure to a model is a very "render fast" way of producing bumps, details andcomplicated geometry.

Bump mapping Normal mapping Displacement mapping


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Normal mapping

- Is a very fast and flexible technique that also works with real time 3D animation.

- Normal mapping is more accurete then bump mapping because it uses color images (RGB-data with 3channels for altering the normal compared to bump mapping just using BW images with 1 channel).

- Normal mapping is faster then displacement mapping.

Model in sculpting program with4 million polygons

Lowpoly model with 500polygons

Lowpoly model with normal mapping


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Using normal maps for sculpt modeling

- An exampel of how diffrent texture maps are used in the face.


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Extreme normal maps for sculpt modeling

- Using Mudbox or Z-Brush you can generate extreme detailed geometry and export it as normal maps

Model by Anto Juricic Toni


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Frankenstein by Anto Juricic Toni


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Reflection mapping- Also called enviroment mapping. Using spheres, a foto of a chrome ball, a cube or other geometric forms tosurround the model with an enviroment.

- This technique works by mapping and image to the reflection attribute of the shader. Making the modelreflect the image.

Images by Gene Miller


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Projection mapping- Beside texturing mapping an model with a UV-map, you can also project an image - much like projecting aslide trough a projector on a wall.


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Projection mapping- Using this technique you can project images from different angels on lowpoly object to create photo realisticresults.

Images by Paul Debevec


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Mathematical textures- The art of fractales, created from matchematical formulas,examples like the Mandelbrot fractal.

- A fractal can exist in 2D or 3D space.

- In Maya you can create wood, leather, noise etc


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Shading network (texture trees)- In Maya you have the ability to work inTexture trees of shaders, textures, fractalesand effects combining it to one shader "master shader"


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Texturmapping - a showcase- Steven Stahlberg is a famous artist within the CG community for his nude studies and pinup girls.


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- Staring out with a sketch of the woman

Material copyrighted to Steven Stahlberg


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- Modeling the woman in Maya



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- Color mapping



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- Bump Mapping



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- Reflection mapping



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- Gore texture for the legs



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- Setup scene in Maya with props and a startup lighting



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Shower panties by Steven Stahlberg


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End of part 5 texturing.

T i i M


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Texturing in Maya

- Assigning Shaders- Texturemapping- Shading trees- Unwrapping UVs in MAYA

- Exporting Models to a 3D paintprogram

Tutorial on unwrapping:http://www.youtube.com/watch?v=P7r4_5n9WXo

H h d


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Hypershade

In this editor you:- Create materials- Shading trees- Utilities

H h d


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Hypershade

In this editor you:- In the attribute editor you can alter and changeyour shader

And texture map it!

H h d


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Hypershade

The image is connected to the color attributeon the shader. This is part of a texture tree.

Also the bump as you might see is a pictureconnected to the bump

H h d


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Hypershade

A shader tree can also be used with a "layer

shader" to combine to shaders in to one. For instace on the car there is one shader for thecar glossiness and another for the paint.

H h d


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Hypershade

In order for the image to display the 3D formneeds to be in 2D-space. On the right yousee an "unwrapped" version of the car.

UV-mapImage / texture

U i g i M


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Unwrapping in Maya

- So why do you need to unwrapthe uv-koordinates to texture them?

U i g i M


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Unwrapping in Maya

- Minimize stretching andgeneral errors.

- This is preparing the

model for texturing with apaint program or such.

Before After

Texture mapped checker texture, onthe lowpoly woman model before andafter an UV unwrap.

Un r pping in M


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Unwrapping in Maya

- UV-coordinate exist on the model in order for so that a3D program can interprete the 3D volumetwo dimensionally.

- What does that mean?

- Practically it means; if you want to texture map your model with an image texture, you need to have a 2Dcoordinate system pointing were on the 3D form theimage should show.

Unwrapping in Maya


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Unwrapping in Maya

- UV space.

UV-editor (A 2D coordinate system) The UV-coordinate in a mess! Unwrapped and layouted UV-

koordinates

Unwrapping in Maya


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Unwrapping in Maya

- Split up the mesh with "extract" command- Use Isolate and UV-texture editor.

- When unwrapping, you have to create

"seems" for the uv's to be abail to "flatten".

(Think of it as how you would skin ananimal or how you would cut pieces of clothing to make a sweater etc)

Unwrapping in Maya


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Unwrapping in Maya

- Make a Lambert and texture map a checker

- Assign the material to the torso.

- Project a planer uv-projection with newuv-coordinates ontop og the torso.

- Cut the uv's with the "cut uv" tool.

- Unwrap the uv's (flattning them likean animal skin)

- Pin one point or more when youunwrap to adjust the size and shape.

Unwrapping in Maya


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Unwrapping in Maya

- Assign the checker to the arm

- Project a planer uv-projection with newuv-coordinates ontop of the arm,


- The select all uv's and unwrap without pinningany uv. Then scale up the uv and unfold and pinuv's to even out the squares.

Unwrapping in Maya


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Unwrapping in Maya

- Assign the checker to the arm

- Project a planer uv-projection with newuv-coordinates ontop of the arm,


- The select all uv's and unwrap without pinningany uv. Then scale up the uv and unfold and pinuv's to even out the squares.

Unwrapping in Maya


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Unwrapping in Maya

- Transfer the UV map to the other arm and handwith the "transfer attribute"

- Use mirror X and delete historiy and move the "shelf" to aunique UV-space.

Unwrapping in Maya


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Unwrapping in Maya

- Use the same teqniques on the hip, legs and feet.

Unwrapping in Maya


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Unwrapping in Maya- Combine and merge the mesh to one.

- Cleanup and Optimize scene (save before)

- Use the Layout function of manually place the diffrentselfs of uvs in the UV-space and assign a material (exlambert).

Exporting as Obj or Fbx


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Exporting as .Obj or .Fbx- You can actually open you model in Photoshop and paintthe texture there. All you need to do is to export it as an.OBJ. Or you can paint it in a specialized 3D paint program

called Mudbox by exporting a .FBX.

- In order to export them. Open the plugin manages and"Load" the .Obj exporter and .Fbx exporter.

- Select the model and export.

Mudbox


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Mudbox

- Mudbox is a specilized program in sculpt modeling andpainting. It works very good with Maya and other 3Dprograms.

Photoshop


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Photoshop

- Photoshop can also import .obj and paint the models. Savethe images you pant by dubbelclick on the layer and save theimage that opens and then texture map the saved image inMaya on the attribute in the shader you would like to map.


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End of texturing part 6

until next time:Read and do the tutorialsof Chapter 7 in the MayaIntroducing.

3d introductorytexturingpart 5/14

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