QUOTE (Uguel)
This is what I tried with Bryce last spring and I must have done something wrong when rotating the cube for I could not get a clean cut like yours.
It can be a pain to correctly line up the objects, certainly as there is no solid view. If in doubt, it is possibly better to make a "fast preview mode" render, this will help show where everything is.
QUOTE (Uguel)
Oh, and once you've got the roof, you will need to fit the house accordingly too ...so will you use booleans to get a v cut wall ?
Yes,
QUOTE (Uguel)
I tried to do the pointed part of the wall by trying to cut a cube with another cube diagonally and I had a hard time and finally gave up.
It can be difficult when viewing in wireframe, as mentioned, make a quick preview render. (untill you get used to wireframe, you could also paint each block a different color for the render)
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OK, Creating a simple roof in "Hexagon". This may seem hard at first, but its just a case of trying it out, and getting used to where and what "things" do.
First open Hexagon, then setup to draw the roof. One way is to draw the end view of the roof then extrude this (there are of course, other ways to create this).
So, at the bottom of the main Hexagon window, first select (1) Orthographic view (this just sets the view to a flat background, it is easier to draw this way). Using the (2) Zoom and (3) pan, move the main window so you can see the grid (as in the pic) When using the pan/ zoom/ rotate view, left click the icon and keep the mouse button down, then move the mouse. Then select (4) snap.

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You would also be best at this time to check that you have the Translate (move) manipulator selected.

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Now to draw the line for the roof. First, on the top menu, select "Lines" then "polyline"

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Now, when you move the cursor, you will see 2 axis appear on the screen, these are your guides, and on the right hand side, you will see a "Properties" box,.. this will give you a readout of where you are on the screen.

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Now, draw the shape of the end of the roof. Here you will see I have made 6 points. When you get to point 6, go to the "properties" box (as shown in the last pic) and left click the little shape under the word "Point", this will make the lines close (point 6 will connect to point 1)

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Now, to extrude the roof. First, change the view from "Orthagraphic" to "Perspective" (ref pic 01,.. click icon 1), then use the rotate view (ref pic 1, its the icon next to 3) until you can see your drawing. Then select (1) Vertex modeling, (2) fast extrude, then (3) click (and hold) the blue arrow (this is for the direction of extrude)

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With the blue arrow still selected, move the mouse and you will see the roof extruded, just make the size as you want.

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When done, you need to close the ends of the roof. Go back to the top menu, and select "Close"

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When you select close, the open ends of the roof will be highlighted (as in the pic), just click anywhere on the highlighted line (on each end)

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Basic roof complete.

Now, I know it may seem difficult at first, and it is quite easy to make an incorrect sellection, but it just takes a bit of practice, and time to get used to where everything is.
NOTE: If when you get to the extrude stage, and the manipulator is missing (so you cannot click the blue arrow to extrude), then first: Ensure that you have the Translate (move) selected (pic 2), and that you are in "Manipulator mode" (if you check pic 1, there are 4 icons, 2 of them numbered 2 & 3, the leftmost of those 4 icons must be selected (blue background).