   Joints and Resting Contacts - How to Resolve?
  Hi Community,I tend to include joints into my simulator. It is impulse based and I am unsing the methods of the IBDS library (written by Jan Bender). So far I am organizing the resting contacts in a contact graph. Now how do joints fit into that picture? Is there a contact graph for joints aswell? Can I mix the resting contacts and the joints in one graph?Any hints are welcome!!Alex   
  You should be able to mix joints and contacts into a single graph, in general. Modern game physics engines typically work this way. Part of the trickiness is that you would be mixing equality and inequality constraints. I don't much about Jan Bender's work, though.Erin Catto provides a nice overview of solving generalized sets of constraints, in his tutorial talk at the Game Developer's Conference in San Francisco each year. You can find his presentations here:Erin Catto's downloadsI would look in the GDC 2009 section, and look at the solver powerpoint (*.pptx) presentation. I think Erin might not have talked about this topic at GDC 2010 (at least there seems to not be a solver presentation in his 2010 area).You can find more general overview on physics simulation (not that you are looking for this) at:Essential Math GDC TutorialI point you there since Erin's presentation is a part of this overall tutorial. Note that the slides on the essential math page are a couple of years old now. They haven't really changed much over the years, but in any case you won't find quite the latest and greatest there. Erin's download page has more recent slides for his portion. Erin's presentation is quite good.;  Great, thanks I will study the documents right away!!!Alex   