Throwback: Karma physics engine user guide

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mpm
Posts: 5
Joined: Mon Apr 17, 2017 12:11 pm

Throwback: Karma physics engine user guide

Post by mpm » Wed Aug 30, 2017 5:01 pm

This might not be popular, but while I have not seen much discussion on these forums about the old Karma engine I think it still deserves
a special mention. MathEngine's user guide for Karma gives a thorough, although dated, introduction to dynamical simulation for entertainment purposes.

You can still pull it from UDN at https://docs.unrealengine.com/udk/Two/r ... rGuide.pdf (from https://docs.unrealengine.com/udk/Two/K ... rence.html) and if not I think I should be able to upload it.

It does not explain how to write your own engine, rather it provides in-depth discussion of many topics and algorithms still relevant today, detailed glossaries, architectural details, and a long list of references in the bibliography section. You can also observe its parlance of the words farfield and nearfield, contrary to broad-/narrowphase which the community seems to have settled on today.

Features:
  • Broadphase: Incremental SAP
  • Narrowphase: GJK, discrete
  • Solver: Force-based Lagrange multiplier method implemented by an iterative LCP solver called "Kea"
  • Tuning: Epsilon (constant added to matrix diagonal for improved convergence) and gamma (Baumgarte) parameters which I believe are equivalent of ODE's CFM and ERP
It would be nice if someone knowledgeable could provide more details about this gem.

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