Hi, as you mentioned the *SetAlign *accepts an *AlignmentFrame *type. In C++ it would have been quite easier to spot that his definition is encapsulated in *ChForce *itself, so it should have been : *spring_force_2->SetAlign(chrono::ChForce::AlignmentFrame::BODY_DIR);*
However, the wrapping just discarded the "AlignmentFrame" enum type, thus flattening the enum options directly inside *ChForce*. In short, it became: *spring_force_2.SetAlign(chrono.ChForce.BODY_DIR)* However, as you can see, *SetAlign *does not allow a generic frame to be used nor a marker (that would have been the proper choice), but it offers only two options: *BODY_DIR *or *WORLD_DIR*. This means that unfortunately you *cannot *tell a *ChForce* applied to *Body2 *to follow *Body1 *with *SetAlign*. Currently there is not a smooth way to use ChForce to achieve what you desire. It is probably easier to go directly to a *ChLoadBodyBody*. Apart from that: I see that you named the variable *spring_force*... if you just need a spring I would recommend you to use ChLinkTSDA isntead! Dario Il giorno martedì 12 dicembre 2023 alle 01:52:57 UTC+1 Dash ha scritto: > Dear Chrono Community, > I have created two bodies and I added a ChForce to the second body. I > would like the force to align with the coordinate system of the first body. > I am using the .SetAlign function but I get a type error. I saw online that > .SetAlign takes an alignment frame, I have tried giving it a marker but it > doesn't work. > > TypeError: in method 'ChForce_SetAlign', argument 2 of type > 'chrono::ChForce::AlignmentFrame' > > Here is a snippet that is causing the problem: > > self.spring_force_2 = chrono.ChForce() > self.spring_force_2.SetMode(chrono.ChForce.FORCE) > self.body_2.AddForce(self.spring_force_2) > self.spring_force_2.SetVpoint(self.marker_2.GetPos()) > self.spring_force_2.SetAlign(chrono.ChFrameD(self.marker_1)) > > Thanks in advance to anyone who can point me in the right direction! > -- You received this message because you are subscribed to the Google Groups "ProjectChrono" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/projectchrono/e884313b-6799-4760-8251-a48ea2b6fe0en%40googlegroups.com.
