Hi Luca, for your question #3, you wrote:
> How can I change the height of the wall without changing the
> elevation of the opening? After the boolean operation I cannot
> use "Show point" for moving down the top face.
Once you have done a boolean on an object, you will have surfaces in it that have "trimming curves" on them.
When you have a solid that has trim curve edges in it, you can't turn on control points for that solid directly, because it would be too easy to pull points for the different surfaces apart which would create gaps in what are supposed to be shared edges.
NURBS works a lot differently than polygons in this way - when you see an edge, it is not necessarily the edge of the "underlying surface" which is what you would control using control points.
I have tried to describe and illustrate this a bit on this FAQ question
here.
That description may help show you more about how the NURBS objects are structured and why you can't just grab the points for any edge that you see and move them like you can in a polygon modeler. In a polygon modeler the edge is always the "end" of the surface, but in that FAQ illustration you can see how NURBS can have an "underlying surface". But it is also this concept of an "underlying surface" that makes booleans work a lot better on NURBS objects than polygon objects, because when objects cut on another, all the surfaces stay the same and just new trim curves on those surfaces are calculated. This helps keep surfaces more simple instead of having them fragment into a ton of little tiny shards like will happen with polygon booleans.
It is possible to turn on points for your object anyway, if you use Edit/Separate to break it into individual surfaces that are not joined to other ones. Then MoI will not prevent you from moving their points around and possibly opening holes between adjacent surfaces.
But a control point edit will probably not produce what you want there, because the holes cut in a surface are kind of embedded in the surface and will stretch when the surface is stretched.
Ok, to get more to the specific case you have here - if you want to shorten that wall you show there, the easiest way to do it in MoI is to draw a line in the Front or Right elevation view for where you want the new top to be, and then use Boolean difference to cut your wall by that line and then delete the top part.
To grow it elevation, select the top face and extrude it up, then select the 2 parts and use Boolean Union on them.
I would like to add some tools to more directly manipulate a face like you might be more used to (maybe you are more used to SketchUp?) but it will probably be a bit before that happens.
One other note - it is possible to actually erase the trim curves to go back to the underlying surface, here is a short tutorial on how to do that:
http://moi3d.com/forum/index.php?webtag=MOI&msg=444.4 so you can do that if you want to completely remove a window or something like that.
Hope this helps!
- Michael
