Change the order of materials
You may want to change the order of how materials are applied to make sure that the visual attributes of your 3D content is to your liking.
Under Objects and Timeline, expand the Viewport3D object for the object that you want to modify. Within the Viewport3D object are containers for the cameras, materials, and lights.
The materials and lights might be contained in an object that represents the world geometry. If so, expand the world geometry container object.
Expand the materials container object, and then select one of the material objects. The face that corresponds to the material is identified on the artboard by a blue bounding box.
Expand the material object until you get to the last node, as in the following image:
In the Materials category of the Properties panel, click the color swatch next to the BackMaterial or the Material property, depending on which side of the face you want to reorder the materials. The materials subproperty editor appears.
In the list of materials, click the material you want to reorder, and then click either Send Material Backward or Bring Material Forward .
The list of materials is at the top of the materials editor. You might have to scroll up to the list of materials by moving your mouse over the little black arrows at the top of the materials editor.