Utilizing Shader Nodes in Blender - Basic Image Texture Node

The Image Texture Node in Blender is a versatile node used to apply an image as a texture to your objects. Here are the main features and how to use it:

Inputs

• Vector: A 3D coordinate that is projected onto the 2D image using the selected projection method. Typically connected to the output of the Texture Coordinate Node. If left unconnected, the coordinate is taken from the object's active UV map.

Properties

• Image: The image data-block to use. You can select or open an image file directly from this node.
• Interpolation: Determines how the image is scaled up or down for rendering:
  • Linear: Regular quality interpolation.
  • Cubic: Smoother, better quality interpolation, ideal for bump maps.
  • Closest: No interpolation, useful for rendering pixel art.
• Projection: Defines how the Vector is projected onto the image:
  • Flat: Projects the image onto a unit square.
  • Box: Projects the image onto each side of a unit cube.
  • Sphere: Wraps the image around a sphere.
  • Tube: Wraps the image around a cylinder.
• Extension: Specifies how the image is extrapolated if the Vector lies outside the regular bounds:
  • Repeat: Repeats the image horizontally and vertically.
  • Extend: Extends the image by repeating the pixels on its edges.
  • Clip: Clips to the original image size and sets exterior pixels to transparent black.
  • Mirror: Repeatedly flips the image horizontally and vertically.

Outputs

• Color: The RGBA color from the image.
• Alpha: The alpha channel from the image.

 

To add a node in Blender, you can press Shift + A and type the name of the node directly. Instead of typing out the entire name, you can often just type the initials of the node, which makes it easier to find and add the node. For example, for the Image Texture Node, you can simply type 'it' to find it.

Additionally, while you can manually create and connect the Mapping Node and Texture Coordinate Node for the Image Texture Node, there's a shortcut. By selecting the shader (in this case, Principled BSDF) and pressing Ctrl + T, Blender will automatically create and connect the Image Texture, Mapping, and Texture Coordinate Nodes for you.

 

In Blender, the Texture Coordinate Node's UV is a coordinate system used to map textures onto 3D objects. UV mapping is the process of wrapping a 2D image texture around a 3D mesh. Here are the key concepts and usage of UV mapping:

Concepts of UV Mapping

• UV Coordinates: Unlike using x, y, z coordinates in 3D space, texture mapping uses u and v coordinates. These represent the 2D space of the texture, with each point indicating a specific location on the texture image.
• UVW Mapping: UV mapping is typically used to apply 2D image textures to 3D objects, but in cases like procedural textures, textures can be generated in 3D space.

Process of UV Mapping

1. UV Unwrap: Cut and unfold the mesh of the object to create a flat layout. This defines how the texture will be applied to the object.
2. UV Editor: Use Blender's UV editor to adjust the UV map. Move, rotate, and scale the UV map to ensure the texture fits well on the object.
3. Apply UV Map: Apply the UV map to the object so that the texture displays correctly.

UV Output of Texture Coordinate Node

• UV: UV texture coordinates taken from the active render UV map. To select a different UV map, use the UV Map Node.

 

 

In Blender, Generated texture coordinates are a coordinate system that ranges from 0 to 1 based on the bounding box of the object. This is primarily used for applying procedural textures and provides consistent texture mapping regardless of the object's size or position.

Key Features

• Coordinate Range: Generated coordinates range from 0,0,0 to 1,1,1 within the object's bounding box. This maintains the same range regardless of the object's size.
• Consistency: Texture mapping remains consistent even if the object's size or position changes. This is particularly useful when using procedural textures.
• Automatic Generation: Blender automatically generates Generated coordinates based on the object's bounding box.

Box Projection

Box projection is a method of projecting an image onto each face of an object. This method is useful for box-shaped objects, such as architectural models. Using box projection ensures that the texture is evenly distributed across each face of the object.

Blend

The Blend option is used with box projection to smoothly transition the texture across multiple faces of the object. Increasing the blend value softens the boundaries between faces, resulting in a more natural appearance. In the example image, the left sphere has a blend value of 0, while the right sphere has a blend value of 0.25.

 

In Blender, the Object texture coordinates of the Image Texture Node map textures based on the object's position and size. This coordinate system ensures that the texture remains consistent with the object's transformations. In the image above, the top cube uses Object coordinates, while the bottom cube uses Generated coordinates. When both cubes are stretched sideways in Edit mode, the Object coordinates maintain the image's proportions without stretching. Despite this advantage, it is advisable to avoid using Object coordinates for objects undergoing real-time transformations, as the image will not distort to match the deformed mesh. Here are the key features and usage of Object texture coordinates:

Key Features

• Object-Based Coordinates: Object texture coordinates map textures based on the object's position, rotation, and scale. This ensures consistent texture mapping when the object moves or transforms.
• Consistent Texture Mapping: The texture remains undistorted and consistent with the object's transformations. This is particularly useful for procedural textures.
• Various Projection Methods: Object texture coordinates can be used with various projection methods. For example, using Box projection and the Blend option allows the texture to transition smoothly across multiple faces of the object.

 

 

In Blender, the Camera and Window outputs of the Texture Coordinate Node are two different coordinate systems used for mapping textures onto objects. Here are the detailed functions of each:

Camera Output

• Camera Output provides position coordinates in camera space. It maps textures based on the camera's position and orientation.
  • Usage: Useful when the texture needs to dynamically change according to the camera's viewpoint. For example, when the camera moves or rotates, the texture adjusts accordingly.
  • Example: Used to make a texture always face the camera or to create texture effects that are visible only from specific viewpoints.

Window Output

• Window Output provides the position of the shading point based on screen coordinates. It ranges from 0.0 to 1.0 from the left to the right and from the bottom to the top of the screen.
  • Usage: Useful for applying textures to specific areas of the screen or for textures that need to change according to the screen's aspect ratio. For example, applying a texture to a specific part of the screen or automatically adjusting the texture based on the screen size.
  • Example: Applying a texture to a specific area of the screen or ensuring the texture adjusts automatically with the screen's aspect ratio.