Export Detailed Simulation Information!

[MuGdxy]

If you need to export Energy/Gradient/Hessian in the backend, this is what you need!

[MuGdxy]

Now, regarding contact, libuipc supports classified contact energy, gradient, and Hessian.

https://github.com/spiriMirror/libuipc-samples/blob/main/python/20_contact_system_feature/main.py

Btw, in uipc, energy/gradient/hessian is scaled by ${\Delta t}^2$.

Cuz, the optimization problem is:

$$ E(x) = \frac{1}{2}|x-\tilde{x}|^2_M + P(x){\Delta t}^2 + B(x){\Delta t}^2 $$

where $\tilde{x}$ is the predicted position, $P(x)$ is the elastic potential energy, $B(x)$ is the contact potential.

So if you need the so-called force (from Newton's Law aspect).

$$ f = -\frac{g}{{\Delta t}^2} $$

where, $f$ is the force, $g$ is the gradient.