Thank you both Dan and Radu for your help ! I did setup is_convex to False but didn't tune the *radius *argument (5th argument). With *radius* set to 0.0001 I do get a contact between the two gears thank you very much ! Can you give me some explanations on what this argument is doing ? The doc is saying "outward sphere-swept layer (when supported)" but I am not sure I get it right.
Best, Antoine Le vendredi 3 octobre 2025 à 09:22:22 UTC+2, Radu Serban a écrit : > Antoine, > > > > Have you ensured that the collision meshes are flagged as concave in the > ChCollisionShapeTriangleMesh > <https://api.projectchrono.org/classchrono_1_1_ch_collision_shape_triangle_mesh.html> > > constructor (4th argument set to false) and provided a non-zero mesh > thickness (5th argument, which defaults to zero)? Please take a look at > how collision meshes are set up in demo_MBS_collision_trimesh > <https://github.com/projectchrono/chrono/blob/main/src/demos/mbs/demo_MBS_collision_trimesh.cpp> > . > > > > --Radu > > > > *From:* 'Antoine Laborde' via ProjectChrono <[email protected]> > *Sent:* Wednesday, October 1, 2025 2:12 PM > *To:* ProjectChrono <[email protected]> > *Subject:* [chrono] Contact detection on mesh objects > > > > Dear all, > > > > I work on watch parts simulation through rigid body dynamics. I had > problems with contact detection between some parts so I decided to build > the simplest scenario where I get the problem. > > This scenario is the simulation of gears (as mesh objects). The problem is > that the teethes of the gears don't collide, they go through each others. > The script does the following: > - load the STL files of the gears > > - create ChBody for each gear > > - add triangle mesh visualization shape > > - add collision shape using ChCollisionShapeTriangleMesh > > - apply a torque to one of the gears using AccumulateTorque() until a > speed of 0.05 rad/s is reached > > > > I am using ChSystemNSC with BULLET collision detection. I checked project > chrono documentation page on collision detection and tuned the contact > envelope and margin but didn't get any result. To make sure it was not due > to the accuracy, I reduced the speed of the gear and set the time step to > 0.001 s. > > When I launch one gear on the other, like throwing a ball on another, the > collision occurs. > > > > I don't have a lot of experience on rigid body analysis so any feedback > would be greatly appreciated ! > > Best, > > Antoine > > -- > > 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 visit > https://groups.google.com/d/msgid/projectchrono/013ce180-1ec7-4d6a-95c1-e6e91e3c81f2n%40googlegroups.com > > <https://urldefense.com/v3/__https:/groups.google.com/d/msgid/projectchrono/013ce180-1ec7-4d6a-95c1-e6e91e3c81f2n*40googlegroups.com?utm_medium=email&utm_source=footer__;JQ!!Mak6IKo!KIcttF-aY_trjz5PerxrXWX2bImARUwfANsEX8FfnOwUFoQ-ke9wZgFmNIKcO100oIy6jvCjFsJEaX974-UFEpQcvuI$> > . > -- 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 visit https://groups.google.com/d/msgid/projectchrono/24355cf3-9096-403d-adf2-0598f7bb9229n%40googlegroups.com.
