@juju It’s impossible to use these method for more than 3 DOF, there is often no analytic solution. You have to use for example Denavit Hartenberg method.
@Manon Nobody works seriously on an IK model of poppy in flowers lab. I began last week to work with ros and openrave for generating an ik solution C++ code with ikfast module (I think it’s also your goal), but I had troubles with my exported collada file of poppy humanoid. I’ll keep you in touch if I’m going forward in that.