CSE 291: Physics Simulation

TA: Chad McKell (cmckell@ucsd.edu)
Office hour: Thurs, 3:30 - 4:30 pm
Office location: CSE Building, B275
UCSD, Spring 2024
Course website: link

HW 0: Physics Simulations in Houdini

April 11, 2024

In today's office hour, we reviewed the following essential steps for creating a single-mass pendulum simulation in Houdini: (1) adding points and parameters, (2) channelling parameter values, (3) creating a pendulum geometry, (4) connecting a geometry to a point, and (5) animating the pendulum using a time-stepping scheme. See the notes below for a detailed description of these steps. The resulting pendulum simulation is shown here. The basic techniques covered in today's office hour can be applied to many other types of physics simulations, such as simulations of mass-spring systems, flocking birds, or n-body problems.


HW 0 Notes

HW 1: Dimensional Analysis and Differential Geometry

April 18, 2024

Today we worked on the HW 1 problems together as a group. To access the notes below, sign in to the Canvas course page and go to Files-> TA Notes-> hw1_notes. The notes contain detailed solutions to each problem as well as a review of concepts relevant to the assignment. Specific topics include: finding dimensionless variables, calculating the null space, computing differentials, finding a change of bases, and taking derivatives of functions on matrices.


HW 1 Notes (link to Canvas)

HW 2 Written Part: Calculus of Variations

April 25 and May 2, 2024

On April 25, we worked on the first problem of HW 2 relating to the calculus of variations. On May 2, we looked at the second problem relating to the least action principle (note that the least action principle is a variational principle that forms the foundation of Lagrangian mechanics). Specific topics included: KKT conditions, Noether's theorem, the Jacobian, and the pullback operation. To access the notes below, sign in to the Canvas course page and go to Files-> TA Notes-> hw2written_notes.


HW 2 Written Part Notes (link to Canvas)

HW 2 Mini-Project: Rigid Body Dynamics

May 9, 2024

Today we programmed a double-rod pendulum in Houdini as a group. We first reviewed the mathematical derivation of the double-rod pendulum equation (note: the derivation is based on the least-action principle). A written copy of this derivation can be accessed by signing in to the Canvas course page and going to Files-> TA Notes-> hw2project_notes. After reviewing the derivation of the equation of motion, we discussed the steps required to simulate the motion in Houdini. The resulting simulation is shown here.


HW 2 Mini-Project Notes (link to Canvas)

HW 3: Elasticity

May 16, May 23, and May 30, 2024

On May 16, we discussed the pullback and pushforward operators. The pushforward is used to derive the deformation gradient for applications in elasticity simulation. On May 23, we reviewed aspects of the continuous and discrete theories of elasticity. On May 30, we discussed how to simulate a single bouncing tetrahedron in Houdini. The notes below contain two concrete examples of calculating the deformation gradient in the continuous setting, the mathematical steps involved in elasticity simulations, a derivation of the discrete deformation gradient, and a brief discussion of the discrete mass calculation.


HW 3 Notes

HW 4: Fluids

June 6 and June 13, 2024

On June 6, we reviewed the basic steps involved in implementing vortex particle simulations in Houdini. The steps include: (1) creating a distribution of point particles, (2) defining particle vorticity strength, and (3) computing the velocity field and position update at every time step. The resulting simulation is shown here. On June 13, we answered follow-up questions about HW 4. The notes below contain troubleshooting tips and guidance for simulating vortex patterns.


HW 4 Notes