Holes in prims

Hello all. Im a little new to SL, and still learning to build and what not. But Im haveing a hell of a time trying to get this to work.

Im trying to use a prim, to simulate a hole in another prim, with out making an avatar invisable. Im trying to make a weapon, and this would help me greatly.

The best way to do tthis is to use single prim with the hollow attribute set, rather than having two prims.

There is no boolean geometry in SL, so a hollowed prim is by far the best way to put a hole in something.

Im not experienced by any means, but after building this mech it taught me alot. Say for instance you have a cylinder and you want to put a port hole in the middle of it. Well technically I don't think you can. You can take the cylinder turn it on its side and use the hollow settings and make it a port hole. But you can't "punch a hole in it" in the side.
You can use your shift copy key and then drag it next to it with the position key. Then you have one cylinder that is solid next to it. and the one in the middle can have the whole, and the one on the end can again be a solid. Now you have three prims that when linked together represent the whole in the side of the cylinder. But you have to fill in the top of the middle prim and the bottom. For this use your end cut key on the hollow prim.
Then make the middle prim that has the whole a window tga. Select this thru textures.
That is how I learned how to make a hole in the side of a tube.
If there is any easier way then those who know can post it.

As a newbie, I'm still puzzled by this.
All I'm attempting to do is punch doors and windows in box prim walls - what's the best way to do this? To be honest the Quake1 level building I used to do some years ago seems more powerful, but admittedly there's a lot I don't yet understand.

To all the newbie builders out there, I strongly recommend visiting the Tower of Primitives. Do a search in world and spend a couple of hours there. It will save you WEEKS of trial and error learning.

The short answer is, you can't. SL does not have tools for punching a hole in one prim by doing something with the shape of another prim. It doesn't work that way here.

Most prims do have a setting that allows you to make a prim hollow on one particular axis. So, for example, you can take a cube, and make it into four connected walls that have no roof or floor. But the only way to get the effect of a window in the side of that figure is to stack three of them, with part of one side cut away on the middle one. And even then, you'll have angled sides on the hole. And you can only cut a single prim once, or maybe twice, depending on the shape...

In most cases, if you see a window that is not an area just mapped transparent, then that window is formed by stacling prims together, like building blocks.

Seek the "Ivory Tower of Primitives", and study the tutorials there. It's worth the time for any builder. Just do a search for "Ivory Tower" in-world.

Thanks Pratyeka and Ceera, I get the idea now, I did try the Ivory Tower a few times, but it seems I was looking for an answer that wasn't there. I was hoping there was a way that wasn't so costly in prims, never mind...

No problem.

Now, one thing that you can do is to use various types of 'tortured prims' to cut back on prim count in other ways. For example, use a cube that is hollow 95%, begin cut 0.00, end cut 0.75, to give you three connected walls, then use a few other prims as necessary to make the walls on the either side of and over a door in the remaining side of that room. If you're careful and creative, you can save quite a few prims.

And I use a lot of alpha-mapped windows, myself. That involves creating (or purchasing) a .tga texture that is transparent where the window goes, and applying it to both sides of a prim. If the widow is square or rectangular, you can use a hollowed cube prim, turned on its side and lined up with the edges of the mapped window and the thickness of the wall, to maintain an illusion of thickness when you look through the wall. That gives you a nice wall with a window in it, using just 2 prims, instead of 4 for the wall + one for the window glass.

If you want a window that is NOT transparent, you can create a box that is 0.001m, thicker than the wall, and position it so it just pokes out on either side, and give it an appropriate texture. However, you can't ever make such a window transparent.

I would call that a "picture" *grins*



Tricky (prim intensive, hard to manage) method for a hole in a prim:

1) make a texture with alpha channel that has the hole in it.
2) apply texture to prim.
3) embed small prims inside the larger prim to construct the edges of the hole.

This is a painstaking process and easily increase the prim count of a wall by an order of magnitude if the edges are complicted. It's hard to manage, because there is no easy way to select the inner prims. It results in lots of hidden faces wasting rendering time.

But, it does work!

I was kinda hoping there was a transparent set that would do it for me... Like the invisprims that make the avatar invisable, but in sted of the avatar, it makes other prims it clips invisable. It would help so much, but i guess it just cant be done... Oh well.

Must be one hell of a view there!

or you could make the whole wall a big texture, then where the windows are make them transparent. You need a program like photoshop to do this, then set the areas where the windows lie as trans on an alpha layer (theres a tutorial or two kicking about) then lob this texture on a prim and you save quite afew prims obv. you still need to leave gaps for doors though.

That's called a wall texture with an alpha-mapped window in it. I make and sell them frequently, often as special orders for customers. Look at the Design and textures forum, for a sticky topic on "Transparency and Alpha Chanels", for excellent instructions on this method.