In order to create an object one must be in land of his own?

[Rhonda Huntress]

You just need permission for these things.  You do not necessarily need to have ownership of the land.  Most places will set the land to group own and then allocate rights to various roles within that group.

[Rhonda Huntress]

You just need permission for these things.  You do not necessarily need to have ownership of the land.  Most places will set the land to group own and then allocate rights to various roles within that group.

[Madelaine McMasters]

Hi hallebarde,

There isn't really any difference between rezzing an already existing object from your inventory and rezzing a new prim from scratch using the build tool. If you can do one, you can do the other.

As Rhonda says, you only need permission to rez to do what you wish. But there are caveats on that permission. Many (most?) places that allow rezzing have auto-return timers running. While you may create thing at those places, they can't stay there forever. After the auto-return delay, anything you rez will be returned to your inventory. For this reason, it would be unwise to start a four hour building project on a parcel that has a 15-minute auto-return limit. Many (most?) public sandboxes have reasonable limits that are usually described at the teleport point or in a notecard you're offered on arrival.

Some places may allow rezzing, but not scripts. If you someday wish to install scripts in something you've created, or even write your own scripts (great fun!), you'll need to find a sandbox that allows both rezzing of objects and running of scripts.

Size is generally not an issue either, though you should be polite and not rezz things that shove other people out of the way or obscure the things they are working on. If the ground level of a sandbox is crowded, you can often rez a little platform on the ground, move it up into the air, either by dragging, or by editing the object position in the build window. If you sit on the platform before moving it, you'll move along with it. Once you have you platform in the air, you can rezz new prims on it.

Eventually you'll want a place to build where you can leave your creation in place for as long as it takes you to finish it. At that time you'll have to obtain your own little parcel or find a friend who's generous enough to loan you a building spot. Again, as Rhonda explained, a friend could give you building permission by allowing you to join a group, and assigning you a group role that has build permissions on their parcel.

Good luck, have fun!

[Bobbie Faulds]

If you own/rent the land, create away to your heart's content. However, do be aware you can't really rez something on top of a mesh object. It will fail. In your motorhome, if it's mesh, you'll need to create a rez station...just a flat prim, outside the home then slide in it. You'll be able to rez on that.

There are many sandboxes available in SL...just do a search then, go to the end of the list and work backwards. The first listed are usually the most popular and have a tendency to be busy and often a target for griefers. If you have a premium membership, there are sandboxes exclusively for premium members that you can use. 

As for terrafoming, that gets tricky. On Mainland you can, for the most part, only change it by +/- 4 meters. Private estates sometimes let you do more, depending on the owner. If you just want to practice, Builder's Brewery has a terrafoming sandbox you can play in. You do have to be a memeber of the BB group and it is free to join. Lots of good building classes there too, btw

Good luck. 

[ChinRey]

I know we're not supposed to comment on other people's answers here but I have to correct an error in Bobbie's. You can build and rez on a correctly made mesh surface. It's only mesh with faulty physics that can cause problems there.

To modify land, you almost certainly need to own it. That is, a landowner can open the land for others to modify but I doubt there are any landowners in SL who has actually done that.

If you want to build, you really want to find a good sandbox. There are lots of them all over Second Life, some popular ones where you can meet others and exchange experiences, some empty ones where you can build in peace.

Building inside a home, even a big one, can be rather cumbersome and of course, there's always a risk you accidentally select the wrong object and retesture or even delete your house rather than your new build...

[Rolig Loon]

Size is only one consideration.  Obviously, yes, you can't create something that is too big to fit on the parcel where you have permission to build.  It's the old "building a boat in my basement" problem.  That's not the only thing to think about, though.  The other major concern is Land Impact (L.I.).  Every parcel of land in SL has a Land Impact allowance; that is, a limit on the total land impact of all objects that can be rezzed there.  The absolute limit is ONE unit of L.I. for every 4.376 sq m of land area.  So, for example, you can rez no more than a total of 117 L.I. units on a 512 sq m parcel.

So what's a L.I. unit?  That's a bit harder to answer without getting technical.  If you are just rezzing simple prims (not mesh objects), then one L.I. unit is the same as 1 prim.  So, if you use 10 prims to make something, it has a L.I. of 10. It makes no difference whether they are 10 tiny prims or 10 prims the size of a house. However, if you rez a mesh object or make any linked object that includes a mesh component, all bets are off.  Generally speaking, those objects have a much lower L.I. than simple prim objects, but not always.  So, if you are buying ANYTHING that you intend to rez, examine it with your Edit tool first.  Look on the General page of the Edit tool to see what its L.I. is.  If it's higher than the allowance on your parcel or if it's high enough that it will raise the total L.I. of all things on the parcel above your allowance, you won't be able to rez it.  Check your parcel's L.I. allowance frequently at World >>> About Land >>> Objects.

Now, if you really want all the technical details, read https://community.secondlife.com/t5/English-Knowledge-Base/Calculating-land-impact/ta-p/974163