How to create metalic object imported from blender

Questions
4

i have discovered why the bottom of object with metalic matérial are black , the top was strange , and found some plant on side .

it is because when i use to const envMap = generator.fromScene( scene ,0,0.1,1300 );

it is create an envMap like it was in the center of the world ( = 0 ,0 ,0 ) and not in the center of the object

but my scene i need is at 160 meter of altitude and my metallic objet is above 160 meter .

so how can i use PMREMGenerator to do like it is at the same position of my metallic object ?

thanks

Edit : i ve found a solution which is not the best practice but it is working . so i take the position of my metal objet , i translates all the scene like this objet is in the center of the world and after i do inverse translation .

var sphereTest  = scene.getObjectByName('spheretest');
            var metalx = sphereTest.position.x ;
            var metaly = sphereTest.position.y;
            var metalz = sphereTest.position.z;
             scene.translateX(-metalx);
             scene.translateY(-metaly);
             scene.translateZ(-metalz);
             
             
             
             const generator = new THREE.PMREMGenerator( renderer );
             const envMap = generator.fromScene( scene ,0,0.1,1300 );
             envMap.mapping = THREE.CubeRefractionMapping;;
            envMap.texture.encoding  = THREE.sRGBEEncoding ;
            sphereTest.material.envMap = envMap.texture; 
            sphereTest.material.envMapIntensity = 1 ;
        
              generator.dispose();
             scene.translateX(metalx);
             scene.translateY(metaly);
             scene.translateZ(metalz);
             
 see the result

metal_objet6
metal_objet61614×912 231 KB

Edit 2 : i want to say that i dont really understand what i m doing , i try and see the result until something working . I ve just discovered that the line envMap.mapping = THREE.CubeRefractionMapping;
is not good , change Refraction by Reflection , no change , remove the line and get same result see the result without this line ( same result that above picture )

metal_objet7
metal_objet71605×911 180 KB

edit3 : it is very great , i have used a cube , apply quaternion and it look like a mirror which spinning . It is like envMap stay at the same position and the object3D can turn .
to simulate night i decrease intensity cube.material.envMapIntensity