SofaUnity obtains forces in the Sofamesh class

[RickYang1]

I used SofaUnity to obtain the forces array in the Sofamesh class in Unity, treating it as the external force acting on the tool. However, when I summed up the force vectors of all vertices as the resultant force and drew the resultant force using the DrawLine of Unity, I found that the direction of the force was reversed when there was no contact. The red line in the figure below shows the force acting on the upper tool. In theory, when a collision occurs, the force acting on the tool should be upward.

Here is my SCN file:
jiaomo.txt
Is it because there is an issue with the contact distance setting of the MinProximityIntersection? If I reduce the contact distance, I am concerned that there may be threading issues. How should I choose an appropriate value.
I have read the relevant content on reaction forces before this, but have not found a suitable answer. I hope you can answer my doubts，Thank you very much

[hugtalbot]

Hi @1044351427

Please consider posting your questions on the dedicated forum : /~https://github.com/InfinyTech3D/SofaUnity/discussions