Wrong distance calculation

[maxwave11]

Hello!

I noticed that returning distance from distance_lower_bound quite unprecise. Seems to be it can be a ditance between AABB's, but not between geometries themselves.

Here's my test when I'm getting different results with different cube mesh positions. Although real distance (closest points) between two objects not chaned.

shared_ptr<BVHModelBase> loadMesh(const char* file_name) {
    NODE_TYPE bv_type = BV_OBBRSS;
    MeshLoader loader(bv_type);
    shared_ptr<BVHModelBase> bvh = loader.load(file_name);
    return bvh;
}

int main() {
    shared_ptr<BVHModelBase> shapeA = loadMesh("d:/dev/collis_models/obj_A.obj");
    shared_ptr<BVHModelBase> shapeB = loadMesh("d:/dev/collis_models/obj_B.obj");
    shared_ptr<BVHModelBase> shapeC = loadMesh("d:/dev/collis_models/obj_cylinder.obj");

    auto* objA = new CollisionObject(shapeA);
    auto* objB = new CollisionObject(shapeB);
    auto* objC = new CollisionObject(shapeC);

    CollisionRequest col_req;
    col_req.security_margin = 0;
    
    CollisionResult col_res;
    collide(objA, objC, col_req, col_res);

    cout << "A" << "\n";
    cout << "distance_lower_bound: " << col_res.distance_lower_bound << "\n";
    cout << "nearest point 1: " << col_res.nearest_points[0].transpose() << "\n";
    cout << "nearest point 2: " << col_res.nearest_points[1].transpose() << "\n";

    col_res.clear();

    collide(objB, objC, col_req, col_res);
    
    cout << "B" << "\n";
    cout << "distance_lower_bound: " << col_res.distance_lower_bound << "\n";
    cout << "nearest point 1: " << col_res.nearest_points[0].transpose() << "\n";
    cout << "nearest point 2: " << col_res.nearest_points[1].transpose() << "\n";

    col_res.clear();
    retirn 0;
}

Output:

A
distance_lower_bound: 0.500393
nearest point 1: nan nan nan
nearest point 2: nan nan nan
B
distance_lower_bound: 0.256608
nearest point 1: nan nan nan
nearest point 2: nan nan nan

Is there any options to get precise distance between geometries?

[maxwave11]

Hm, found that there's a method distance from <hpp/fcl/distance.h> which calculates distance with correct value.