Fish Scales in Blender: How to Cover Any Object With Scales (Geometry Nodes)

Summary

In this tutorial, Chris Bailey from CG Cookie demonstrates how to procedurally create fish scales on a surface using Blender's Geometry Nodes. The process involves creating an offset pattern by manipulating mesh subdivisions and using a plane as a base. Bailey introduces the concept of using a 'Triangulate' node to create an 'X' pattern, which is essential for the alternating scale pattern. He then details how to use an 'Instance on Points' node to place a scaled circle (simulating a fish scale) at each vertex. The tutorial also covers adjusting the scale pattern to fit different types of objects, aligning the scales to the surface normals, and applying a material to the scales for a realistic appearance. Bailey concludes with tips on fine-tuning the scales' appearance for various objects and encourages viewers to experiment with the technique.

Takeaways

• 🎓 Chris Bailey from CG Bailey Film collaborates with CG Cookie to teach how to procedurally add fish scales to a surface using Blender's Geometry Nodes.
• 🐟 Fish scales have a complex, interlocking pattern that can be replicated using Geometry Nodes to create an alternating offset pattern across a mesh surface.
• 📐 The tutorial begins with setting up a plane and using Geometry Nodes to create a grid of scales based on the mesh's vertex points.
• 🔄 To achieve the offset pattern, Bailey uses the Triangulate node to create an 'X' pattern in the mesh, which helps in placing scales in a staggered formation.
• 🔢 The Attribute Statistic node is used to determine the maximum index of edges in the mesh, which is crucial for selecting the correct edges to subdivide and place scales.
• 🧵 A combination of math operations and Geometry Nodes is employed to select and manipulate specific edges, creating the base for the staggered scale pattern.
• 🔲 The tutorial demonstrates the use of Mesh Primitives to create a circle that will serve as the scale shape, which is then manipulated to form the distinctive scale pattern.
• 📏 The scales' size and rotation are adjusted to fit various types of objects, emphasizing the need for customization based on the object's mesh density and curvature.
• 🌐 To ensure the scales align properly with the surface of different objects, the Align Euler to Vector node is used, which requires the normals from the base or triangulated mesh.
• 🎨 Material and shading are applied to the scales in the end, with a demonstration of creating a gradient texture for a realistic fish-scale appearance.
• 🔧 The process involves several advanced techniques in Geometry Nodes, such as transferring attributes, manipulating vertex positions, and using math nodes for customization.

Q & A

What is the main topic of Chris Bailey's tutorial?

The main topic of the tutorial is how to procedurally put fish scales onto any surface using geometry nodes in Blender.

Why are fish scales considered complex to model?

Fish scales are complex because they have a repeating pattern of disc shapes that interlock and overlap in a specific alternating way, creating an intricate surface.

What is the first step in creating the fish scale pattern using geometry nodes?

The first step is to create more mesh subdivisions to have more vertices to work with, which will be the basis for placing the scales.

How does the tutorial suggest to create an offset pattern for the fish scales?

The tutorial suggests using a 'triangular' node to create an X pattern cut in the mesh, which helps in achieving the offset pattern required for the fish scales.

What node is used to separate the new edges created after the mesh is triangulated?

The 'separate geometry' node is used to separate the new edges based on their index numbers.

How can you determine the index number to use for separating the edges?

You can use the 'attribute statistics' node to find the maximum index number of edges in the mesh before and after triangulation to determine the correct index number for separation.

What type of geometry is used as the base for creating the scales?

A mesh circle is used as the base geometry for creating the scales, which is then transformed and shaped to resemble fish scales.

How can you adjust the scale size for different types of objects?

You can adjust the scale size by using a 'transform' node and a 'combine XYZ' node to create a single variable that controls the scale of all instances.

What is the purpose of using the 'align euler to vector' node?

The 'align euler to vector' node is used to align each instance of the scale individually based on the surface normals of the mesh, ensuring that the scales follow the curvature of the object.

How can you set a material to the scales in the tutorial?

You can set a material to the scales by using the 'set material' node and creating a new material in the shader editor, which can then be assigned to each scale individually.

What is the final step suggested in the tutorial to enhance the appearance of the scales?

The final step is to create a gradient texture and use a color ramp to give the scales a realistic and visually appealing look, with the base of the scale being darker and the tip lighter.