Issue #463 closed
Steven Peters
created an issue

There used to be code that would rotate the fdir1 vector into the local coordinate frame of the geometry object, but this code is no longer active. This needs to be found and fixed.

Comments (15)

  1. John Hsu

    we need to recover the old bit of code to make fdir1 make use of body-centric frame, see this bit of code that was lost in translation.

    This will lead to better friction behavior rather than the global frame friction pyramid setting when vehicles are changing orientations.

  2. Mike Purvis

    Sorry to resurrect this 2-year-old ticket, but I'm struggling with understanding what frame fdir1 is specified in. With no way to visualize the friction (GA), I'm left basically referencing ODE documentation (cf).

    Is there a Gazebo doc I'm not seeing which describes what the deal is with friction?

  3. Jim Hoekstra

    I also ran into the problem that fdir1 does not seem to rotate together with the robot, but stays relative to the world frame. Am I missing something or is there still an issue with fdir1?

  4. Andrea Ruzzenenti

    OMG thats's why my simulation is not working anymore! I spent one week trying to understand why friction direction seems to be set in the world reference frame and not in the robot one! Please fix that commit!

  5. Jeremy White

    Just a side note, as I've explored this (trying to get a 4 wheeled FRC robot to behave), I have never encountered this bug 'in production'. That is, the way the collisions are chosen mean that my wheels are always the first element in the collision code, so the the fd2 code stanza never triggers. I imagine that if something else with an fdir1 was on top of my wheels I might see an actual problem. So I wouldn't jump to the conclusion that this is the key to your issue.

  6. Log in to comment