Roof - How to proceed

[cwailes]

Everyone,

this is my first attempt at creating a model in VW2008. My next step that I want to do is add the roof. How do I proceed using the creat roof tool? I went to the second floor selected the exterior walls and it gave me an error saying there is not enough walls. So I tried adding a wall where the stairs are and it said the roof is too complex. How would any of you create the roof structure for this house. PLEASE HELP!! I have attached screen shots of the first and second floors. Hopefully, this will give you an idea of my dilemma.

Edited February 24, 2008 by ccw

[CipesDesign]

ccw, try first: drawing a polygon that traces the wall line of the roof. Select the polygon and try the "Create Roof" command. You might still get the "too complex" error. If so, you can usually work around this by using two (or more) different roof objects. You'll need to decide how to break the whole (too complex) roof into more manageable pieces.

In the example you attached there is an angled space which could be throwing things off. Although I do no have your exact dimensions, I have attached below two quick examples based on your shape. The first one was created from a polygon that traced the entire perimeter. As you can see, what VW's does with the angles is probably not what you're looking for. The second example used two poly's: one for the whole shape minus the angled bump out, and a secnd one for the angled bump out. After creating the second angled roof, I clicked on the edge of it that joins the larger roof and chose "gable end" from the ensuing dialog.

The more you experiment with the roof tool(s) the more you'll find out about what works and what doesn't. Hope that helps...

[PS: sorry about the gray (erroneous) lines. They are the page extents and should be ignored as they are not part of the roof.]

Edited February 24, 2008 by CipesDesign

[cwailes]

Thanks Peter. Another question, since this is a two-story house will it automatically create the first-story roof when I creat the second story roof, or do I have to create them both seperately? Also, the back portions of the second story are actually supposed to be interior walls, only the left, front and right are seen from outside of the house, so will this change how I should go about creating the roof structure?

[Jonathan Pickup]

without seeing your project is it hard to tell you what to do. But, these questions need to be answered:

when you create the drawings, and you draw the upper floor, will you show any of the lower roof. If so, you will have to make 2 roofs.

If you want to make one roof, if can be made to span over 2 floors, just set the correct bearing height for the lower roof.

VectorWorks will not know what you want, you have to give it enough information to make the roof. Sometimes the create roof command will not make the roof. In this case use the Roof Face command.

If anyone wants all my roof tips and tricks, they are in my Architect tutorial manual.

[CipesDesign]

All of those are good questions. No, VW's will only create a roof at one plate height (although you can modify each side's plate height after creation). If the upper level roof continues all the way down to the main level plate, one way to achieve it is to ungroup the roof object. You will end up with a bunch of "roof faces" and you can "add surface" or "subtract surface" from these.

[cwailes]

I have attached another photo of the look I am trying to achieve in the first thread, called "Example.jpg". I just don't know how to proceed in doing this.

Also, why is it when I tell it to create roof from the walls, that if I let it create on the same layer as the walls it matches up to the walls. However, if I tell it to place the roof say on the roof layer, it (the roof) is much higher that the walls when I view in the elevation VP, why is that?

[Tom G.]

One has to know how to frame the roof before it can be drawn. And sometimes VW can show you how to frame it without a clear understanding of how to solve the problem. This is not one of those times. In this case, if the front roof springs from the top edge of the second story floor and the rear or back roof springs from the top of a second story wall, then use Roof Faces and extend and edit until they come together at their peaks. Then go back to the front-side roof and either do the same with the wrapping brow (or shed roofs), set to the top of the same floor line (higher than your first story wall plates), or draw a large polygon and Create Roof. Then ungroup and discard the back roof planes and then adjust the front remaining roofs to tie into the valley of the first upper story roof. There is no quick way to do this, however once you get the knack for solving for similar roofs, you'll have bullet proof sections to show your framer how to proceed.

Edited February 25, 2008 by tguy

[Pat Stanford]

I believe that the bearing height you give to a roof is an absolute height above the layer it is on. That means that if you have your roof layer set to the 9' bearing height and you tell the roof to have a 9' bearing height, then the roof objects are actually at 18' bearing height.

Try setting the Z value for your roof layer to 0 and see what you get.

Pat

[CipesDesign]

Pat is correct regarding "z" values, and I've always found that to be a faulty(and counter-productive) way to look at it. I always use the exact same "z" values for my roof layer(s) as the layer that contains the walls on which the roof(s) bear. That way I can model the roof(s) right in the floor plan layer and then cut and paste in place (or simply move via the OIP) into the roof layer without having to calculate the difference in "z" values...

Tguy is also correct in asserting that one must understand how to build the roof (or any other part of a structure) before attempting to model it. The software is just a tool. Sometimes I call it my $2000 pencil ;-)

[michael john williams]

My basics:

Always have different roofs in different layers, even porches, this gives flexibility for changing roof heights / levels, etc.

Even roofs at the same level should have different layers.

I find the offset from layer level or bearing height not very accurate.

Large or complex roofs shouls be broken down into different shapes if the too complex thing comes up.

if too complex comes up, before giving up, try forming pitches, slopes, hops, gables, etc in a different sequence. This usually makes the roof not complex and work even though its the same roof.

[islandmon]

Instead of different Layers for the different Roof Faces ... i prefer to create Hybrid Symbols for each Roof Face, then use one or more Layers to compose them. Each Symbol contains everything necessary to Model that piece of the structure. For simplicity & consistency all pieces are 'built' on the Base Elevation '000'

[Dieter @ DWorks]

I also use 1 layer for my roof, and this layer has 0 as its base elevation, this way you can better define how hight the roofcomponents should be. I also put other thins here that are attached to the roof.

[mike m oz]

I do as Peter Cipes does and set my roof layer(s) to have the same Z as the layer of the storey(s) they are associated with. I then don't have to do any arithmetic when I am definig the roof(s). More obvious and simpler in practice.