Alternatives to Crate Training
There are alternatives to crate training, but they may not deliver the best results. Paper training, for instance, does not work well since it basically teaches your Rottweiler that it is acceptable to urinate inside. It is difficult for a puppy to understand why it is ok to urinate on the paper and why it is not just an inch or two from it. Also, paper training takes double the work: first you need to teach your puppy to go on the paper and then you must teach it to no longer go there and go outside.
Another alternative is to wear an umbilical cord if you are home for most of the day. Basically, attach the leash to your belt or if you have a nylon leash with a loop as a handle, put it around your waist, tighten it by inserting the end of the leash through the loop handle and then clip it on your pup. This allows you to keep an eye on your pup for most of the day so you can recognize swiftly signs of needing to go potty and you can take swift action and head outside. However, you ultimately want to crate your puppy at night.
Finally, a small area of the house may be used. You want to obviously use an area easy to clean up such as a tiled floor or wood floor. Make the area comfy with blankets and put a water and food bowl. You want this area snug so your puppy does not feel compelled to urinate or defecate in one corner. You also want to be able to see your puppy at all times, so use baby gates or other barriers you can see through.