Help with a building tutorial from the IToP

Hello building experts.

This is from the 3rd floor of the IToP and there's no notecard for it so I thought of asking here:

How did he do the last 2 steps in this pic:

http://img90.imageshack.us/img90/4270/tut01002cx0.jpg

In the last two steps, he starts with the second floor of 4 straight walls, tilts two of them at 45 deg in one step, and then tilts the other two ending up with the roof on the last step on the left of the picture.

There's a lot of material missing after these operations and I couldn't duplicate the steps by cutting the walls, so how did he do it?

I could duplicate the roof with a single box which is then hollowed and tapered that results in the same shape, but if you have any idea how he did this with the 4 separate walls in this pic please chime in.

And another question... Is there a way to move the axes from the center of a prim so that it can be rotated around a different point other than its center?

Thanks

Are you sure the second floor is made of 4 walls? Looks to me like he's used a hollowed cube for the second floor and tapered on both the X and Y axes to get the pyramidical roof. I've made roofs this shape using a tapered cube, saves on prims, 1 instead of 4.

The plywood texture on the third last stage looks to me to flow round the corners, which suggests its a single prim to me. The fourth last stage looks to have a solid cube for the second floor, hollowed in the next stage and tapered in the last two stages.

Alternatively, if the second floor is made of 4 wall prims you could still do it, I think.

Say the wall prims are 0.1x x 5y x 5z. You could taper on the y-axis to make triangular walls, which you then rotate and move to form the pyramid roof. Aligning them would be a bit fiddly, and the other approach is much easier and uses fewer prims.

Haven't tried it, but I think it would work.

Wulfric:

You're right... the roof is one cube, hollowed and tapered on both X and Y.

He did some shift-copying of walls on a previous step and I assumed he was doing the same with the roof. Duh!

Thanks for the help.