Is this still possible for objects with an irregular shape? Because for those objects, there's no defined equation that links its surface area and volume with its radius. For example, a Pepsi bottle. The only way to find the exact volume is via integration. But how about the surface area and after that how to do dA/dr?

Is this still possible for objects with an irregular shape? Because for those objects, there's no defined equation that links its surface area and volume with its radius. For example, a Pepsi bottle. The only way to find the exact volume is via integration. But how about the surface area and after that how to do dA/dr?

All help appreciated. Thanks!