BACK TO TEACHING HOMEPAGE

BACK TO COURSE HOMEPAGE

    
     

GA 3311: Materials and Lighting

In this class students will be introduced to materials, textures and lighting strategies to add detail and realism to objects without adding complexity to the model. Students will simulate real world surfaces containing reflection radiosity and other effects.

  
     
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Week 4: Texturing Phun with Photoshop, Cameras, More UVs

How to Tile a texture Without Seams-
CLICK HERE FOR THE LINK. Go from this:
to this:

How to Define a custom brush-
CLICK HERE FOR THE LINK. Go from this:
to this:

Creating "lived-in" Textures-
The Animated Gif below goes through several states which we will examine in class. The entire image is handpainted in Photoshop (does not use photo source) and is the texture for a wooden table.

1. The base layer is created by using both the Motion Blur Filter and the fibers brush.
2.Using a Multiply layer and a complimentary tone of blue, a soft pass was put down at a very low opacity to scuff up the table surface. Using quick noodling strokes and then erasing back in gives the best look.
3.Using another multiply layer, the creased corner were darkened to simulate so of the effects that Ambient Occlusion would have on the surface. Alternately, bake your AO texture at this step.
4.Using a Darken or Multiply Layer, now oyu can add further age on the surface and bake in shadows based on objects that might be sitting on the table, further faking AO.
5.Next I want to scuff up the corners an give the look of exposed, non-treated wood. This is done by using a very small brush size in ligher beige tones, and stippling the surface. I use a Photoshop Bevel and Emboss Layer style with a color just slightly darker than the surounding main wood tone to offset this lighter section.

6.With a custom Brush Shape, I add coffee stains in the upper right corner of the top of the desk.
7. Next, using another motion-blur based layer, I add further scuff from some lighter tones near the edges which might be sanded down over time.
8. Finally, I create a new layer, set it's blend mode to Overlay, and add some lighter tones, first in broad flat strokes, then with smaller noodling strokes to produce a dusty look.

 

 

Creating Tileable Textures from Scratch-
CLICK HERE FOR THE LINK


Cameras and Lenses-

Angle of View-In photography, the measure of the angle of a lens' view. As you adjust a camera's focal length, the angle of view narrows and expands, causing objects to get larger or smaller in the frame. In Maya, the angle of view is simulated by zooming the camera. The Default Value is 54.43 which is niether wide angle or zoom. Adjusting this value will also adjust the Focal Length to correspond:

Focal Length-There are two ways to make an object larger in the frame. You can either move the camera closer to the object (Dolly) or adjust the lens to a longer focal length (Zoom). In photography, the distance from the camera lens to the film plane that determines the angle of view.
In Maya, a focal length constraint is useful for controlling the angle of view in a scene.


Camera Scale-Scales the size of the camera relative to the scene. For example, if Camera Scale is 0.5, the camera's view covers an area half as large, but objects in the camera's view are twice as large. If the Focal Length is 35, the effective focal length for the camera would be 70.

Near Clip Plane-This number controls the closest distance at which objects will render.
Far Clip Plane-This number will control the furthest distance at wich objects will render.

For Hardware rendering, Vector rendering, and mental ray for Maya rendering, this represents the distance of the near and far clipping planes of perspective or orthographic cameras. The default setting for Near Clip Plane is 0.1 and for Far Clip Plane is 1000.
For Maya software rendering, by default Auto Render Clip Plane is on (see Auto Render Clip Plane), and the Near Clip Plane and Far Clip Plane values do not determine the position of the clipping planes. See Auto Render Clip Plane.
If the distance between the near and far clipping planes is much larger than is required to contain all the objects in the scene, the image quality of some objects may be poor. Set the Near Clip Plane and Far Clip Plane attributes to the lowest and highest respective values that produces the desired result.

Rendered in Mental Ray:

Camera Aperature-The height and width of the camera's aperture or film back, measured in inches. The Camera Aperture attribute determines the relationship between the Focal Length attribute and the Angle of View attribute. The default values are 1.417 and 0.945.

Film Aspect Ratio-The ratio of the camera aperture's width to its height. Maya automatically updates the Film Aspect Ratio (and vice versa). The valid range is 0.01 to 10. The default value is 1.5.

Depth of Field-If on, some objects in the scene are sharply focused and others are blurred or out of focus, based on their distance from the camera. If off, all objects in the scene are sharply focused. Depth Of Field is off by default. THERE ARE 3 IMPORTANT VALUES:
Focus Distance
The distance from the camera at which objects appear in sharp focus, measured in the scene's linear working unit. Decreasing the Focus Distance also decreases the depth of field. The valid range is 0 to ·. The default value is 5. The best way to find the focus distance is to use the Distance Measuring Tool.

F Stop
The range of distances from the camera within which objects appear in sharp focus (the depth of field). The range of distances is centered on the Focus Distance. The range is smaller toward the camera and larger away from the camera. The valid range is 1 (small depth of field) to 64 (large depth of field). The default value is 5.6.
Focus Region Scale

Scales the Focus Distance value. The valid range is 0 to ·. The default value is 1.


Enviornment-This Value controls the color of area left in the alpha of a render. It is set to black by default.

Transferring UVs -
A great reason to use this feature would be if you have UV mapped a higher poly mesh and need to use a still unmaped lower poly object in your scene. Lets look at these two basketballs, which while would normally be simple enough to remap, illustrates the potential of this tool rather effectively. In image 1, we have not yet transfered our UV mapping. The ball on the left has been planar mapped, and the lower poly ball on the right has just the default (somewhat cyclindrical) uv layout.

In step two, we open the Mesh-->Transfer Attributes options box. Here we are going to alter 2 things, the UV to current, and the sample space to local.

When we hit apply, the planar mapped UV set is applied to the low poly ball.


Watch this Video on Displacement and Bump mapping:

Homework: Texture all of the objects in your alleyway scene, producing color channels for each object, and bump maps where appropriate. Specifically, you will need to include textures for:

-1 element that is Brick, Cinderblock, and/or Builder's Stone
-1 element that is Wood, Wood planked, or Wood Paneled
-1 element that is Stone

Where you apply these textures is up to you. Adjust values for your camera. Render out a final image that will be submitted, along with your scene file in week 5. Render out a second version of the scene at night.

Awarded Andrew's Gold Medal of Awesom-i-tude:


Image by Yang Shelong
Image by Sean Currey

Image by Nhathy Ngo
Image by Rob Howland

Image by Oliver Barraza
Image by Lee Farrell

Image by Brandon Jones
Image by Kendra Doyle

Image by Lee Farrell

Image by Dylan Atari

Image by Di Ye

Image by Doug Crawford

Image by Julia Gonclaves
Image by Erik Davis

Image by Kai Cabrera

 

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