Habitat Designer
2017-07-26, 06:24 PM
Creating a mansard roof by extrusion ( with an irregular L-shaped plan).
I had a lot of questions on this subject. I managed to answer most of them myself but am posting my work process in order to generate some constructive discussion.
I am trying to create a mansard roof, rather unusual in plan, somewhat L-shaped and so roof by footprint will not do.
I thought that Roof by extrusion was the tool that I should be using.
The standard way of using this tool is to create a profile and extrude it.
However, what happens if the profile needs to change at various points on its journey?
If you look at my attached image you will understand what I am trying to achieve.
18 07 17a.jpg
I created a piece of mansard roof using roof by extrusion tool.
I have used the vertical opening tool on my roof to cut out a portion of the roof out in plan. And I have added a second piece of 75 degree roof. Only problem is how to join 2 pieces of roof?
use join/unjoin roof tool. This only works with roofs created by footprint? At any rate, it doesn’t work here.
I thought I might use cut geometry tool.
I thought I could use tool to cut void in small 75 degree segment of roof and then delete top part. Since I learnt 3d modelling in 3d studio Max and MicroStation I thought in terms of trying to Boolean 2 roofs.
It requires a family instance to cut with. It allows me to select one segment of roof but not second. But is not roof a family instance? At any rate this will not work.
If I use join geometry tool.
So I try join geometry tool and I make some progress. It removes “Boolean” part of small 75 degree roof and at least this gives us a valley line. See image
So now I want to cut away a portion of the 75 degree roof. However, Architecture > Opening gives us a very limited range of techniques when you want to Boolean.
So the only real option is Use conceptual modelling tools and model a void component in place.
Architecture> Component> Model in place > void
I start by setting a plane by picking a plane. See image 26 07 17c
I then start sketching a void which I can extrude.
If you try to exit sketch mode at this stage you get an error message like this. 26 07 17d
Presumably voids are only allowed if they cut away from something. They cannot exist in a project in themselves.
This is what I am left with ( image 26 07 17e) . I suppose I could use another void component to clean this up but surely there is a simpler way to clean up this junction?
Surely at some stage I must join these two roofs or how else will I get a clean junction by attaching walls to roof ? ( it is not clean now).
Does anyone have any thoughts on how to manage this work process?
I had a lot of questions on this subject. I managed to answer most of them myself but am posting my work process in order to generate some constructive discussion.
I am trying to create a mansard roof, rather unusual in plan, somewhat L-shaped and so roof by footprint will not do.
I thought that Roof by extrusion was the tool that I should be using.
The standard way of using this tool is to create a profile and extrude it.
However, what happens if the profile needs to change at various points on its journey?
If you look at my attached image you will understand what I am trying to achieve.
18 07 17a.jpg
I created a piece of mansard roof using roof by extrusion tool.
I have used the vertical opening tool on my roof to cut out a portion of the roof out in plan. And I have added a second piece of 75 degree roof. Only problem is how to join 2 pieces of roof?
use join/unjoin roof tool. This only works with roofs created by footprint? At any rate, it doesn’t work here.
I thought I might use cut geometry tool.
I thought I could use tool to cut void in small 75 degree segment of roof and then delete top part. Since I learnt 3d modelling in 3d studio Max and MicroStation I thought in terms of trying to Boolean 2 roofs.
It requires a family instance to cut with. It allows me to select one segment of roof but not second. But is not roof a family instance? At any rate this will not work.
If I use join geometry tool.
So I try join geometry tool and I make some progress. It removes “Boolean” part of small 75 degree roof and at least this gives us a valley line. See image
So now I want to cut away a portion of the 75 degree roof. However, Architecture > Opening gives us a very limited range of techniques when you want to Boolean.
So the only real option is Use conceptual modelling tools and model a void component in place.
Architecture> Component> Model in place > void
I start by setting a plane by picking a plane. See image 26 07 17c
I then start sketching a void which I can extrude.
If you try to exit sketch mode at this stage you get an error message like this. 26 07 17d
Presumably voids are only allowed if they cut away from something. They cannot exist in a project in themselves.
This is what I am left with ( image 26 07 17e) . I suppose I could use another void component to clean this up but surely there is a simpler way to clean up this junction?
Surely at some stage I must join these two roofs or how else will I get a clean junction by attaching walls to roof ? ( it is not clean now).
Does anyone have any thoughts on how to manage this work process?