Contact

Normally, material inside a simulation only interacts with its own bonds. Contact makes regions interact without touching — for example two separate parts that can press against each other, or one part that can hit itself. When regions come close, contact forces push them apart so they don’t pass through each other.

This is mostly used for impact, assembly, or multi-body problems. For a single part under tension or bending, you almost never need it, and it costs extra compute time, so leave it disabled unless you have a reason to enable it.

Turning it on

Toggle enabled to activate contact for this model.

Contact models

A contact model pairs two regions and defines how they push apart:

Setting	What it controls
Name	A label for the contact model.
Contact type	The kind of contact calculation.
Contact radius	How far apart two regions must be before contact is considered.
Contact stiffness	How strongly regions are pushed apart when in contact.
Contact groups	Which pairs of blocks can contact — a master block and a slave block.

onlySurfaceContactNodes restricts the check to the surface points, which is faster for large models.

When contact is checked

searchFrequency controls how often the solver looks for new contacts. Checking every step is most accurate but slowest; checking every few steps is faster but can miss very fast-moving contact.

Tip: contact settings are numerical, not physical. Different stiffness or radius values can change your results, so tune them only if you understand why you’re doing so.