modeling Merge multiple meshes into one single mesh ...
There are two methods of combining meshes that I know of; The first uses the addon BoolTool:. Select the separate objects that you want to combine. Press Ctrl+Numpad +, to perform a union operation. Press Ctrl+Shift+Numpad Enter to apply the operation. Your separate pieces will now be combined, with new geometry created at the intersections, forming one solid mesh.