CGI Flashcards
exam
What is the importance of CG Math in Houdini workflows?
It connects mathematical concepts to practical applications in computer graphics.
What are the main topics covered in the CG Math semester schedule?
- Numeral systems
- Trigonometry
- Vectors
- Matrices
- VEX
- Rendering
What is an Integer?
Whole numbers (positive, negative, or zero).
What defines Rational Numbers?
Fractions like ½, ¼.
What are Real Numbers?
Numbers that include all decimals, e.g., 3.14.
How are different types of numbers used in Houdini?
They define geometry attributes such as position, color, scale.
What is the 2D Cartesian Coordinate System?
(x, y)
What is the 3D Cartesian Coordinate System?
(x, y, z)
What is the difference between left-handed and right-handed coordinate systems?
Left-handed (Unreal Engine) vs. right-handed (Houdini uses Y-Up).
What does the command @P += {1, 2, 3}; do in Houdini?
Moves an object in 3D space by adding 1 unit to X, 2 to Y, and 3 to Z.
What are the basic math operations covered?
- Negation
- Multiplication
- Division
- Powers
- Roots
How can you animate the size of a sphere in Houdini?
Using the power curve: f@scale = pow(@Time, 2);
What is Summation in mathematics?
Adding values (∑).
What is Product in mathematics?
Multiplying values (∏).
What does Percentage represent?
Scaling a value between 0 and 1 to 0–100%.
How do you normalize the height of points based on percentage?
f@percentage = fit(@P.y, 0, 10, 0, 1) * 100;
What does the Clamp function do?
Limits a value to a specific range.
What is the purpose of the Fit function?
Remaps a range to another range.
What does the Modulo operation (%) do?
Finds remainders.
What are the basic geometrical structures in Houdini?
- Points
- Vertices
- Primitives
Why are triangles commonly used in geometry?
Simplicity and guaranteed planarity.
What are the Houdini data types introduced?
- int
- float
- vector
- matrix
- string
What does v@dir = {1, 0, 0}; represent in Houdini?
A vector pointing along the X-axis.
What trigonometric functions are covered?
- Sine
- Cosine
- Tangent
What types of noise are discussed?
- Perlin
- Simplex
- Fractal
How can you drive movement with sine and cosine in Houdini?
@P.y = sin(@Time);
What are the vector operations covered?
- Addition
- Dot product
- Cross product
- Normalization
What is the purpose of matrices in Houdini?
For transformations (rotation, scaling, translation).
How do you rotate points around the Y-axis?
matrix3 rot; rotate(rot, radians(45), {0, 1, 0}); @P *= rot;
What does VEX programming allow in Houdini?
Procedural and efficient manipulation of geometry.
How can you add random noise to a position in VEX?
@P += noise(@P) * 0.1;
What are the types of transformations in Houdini?
- Scaling
- Translating
- Rotating
What is the significance of the order in matrix multiplication?
It affects the final transformation result.
What does raytracing in rendering involve?
Calculating light reflection and shadows.
What are the types of curves explained?
- Bezier curves
- Polynomial curves
What algorithms are included in Computational Geometry?
- Voronoi fracture
- Triangulation
How can you break an object into pieces in Houdini?
Using the Voronoi Fracture SOP.
