Modeling residential style roofs

[tim.101799]

Typically my office works on standard commerical style buildings (masonry, flat roofs, ect..), but my current project has a very residential feel to it and I am having some issue modeling the roof. Visually I have been able to model the roof so it looks correct, but I am not starting to second guess what I have done so far. My main concearn is how much of the modeled rood & structure I will be able to use in sections & details.

1. Should I model the roof as seperate elements: when I model floors I have a structural floor (conc. slab or conc on metal deck) and a seperate finish floor on top pf the structural floor. Should I do the same with roofs. Have a structural roof the thickness of the trusses or framing, and a seperate finish roof that would incluse the roof sheathing and finish. This would allow me to let my finish roof over hang the structural roof creating the proper drip edge in section. I could then apply a roof fascia to the structural roof and the finish roof (sheathing & shingle) would be ablove the fascia.

2. Rakes at gabel ends: Typically the rake at a Gable end is much thinner in section than the main roof structure. The main structure may be 2x12 with the rake is frames out of 2x4 or 2x6. Should the rake portion of the gable end be modeled seperately and then locked to the main roof?

[tim.101799]

The attached image is of a secional view where a roof changes slope from 6/12 to 12/12. Is there anyway that I can join / clean up the model so the roof structures intestect cleanly?

[tim.101799]

here is another. Below are a couple of images of a 3D section taken at a roof dormer. The first image is small scale to give you an idea of what the roof looks like and the second image is a blow up of the problem area.

As you can see in the blow up, the dormer roof & fascai project into the structure of the main rood below. In elevation and 3D views things look perfectly fine, but it is a different story when I cut a cross section. Can I get the dormer to sit on top of the main roof below it and not project into it.

[ford347]

Use the join roof tool for the dormer problem. That will join the dormer roof to the face of the mainspan roof and get rid of the chunk of roof you are showing in your image.

As far as the split pitch, use a roof by extrusion. That will keep the roof as one and make this a smooth transition. Only problem is you don't have the convenience of a footprint roof with the pitch and wall association. But if you design isn't going to change much, then this should work fine. If you do stick with a footprint roof, just use the edit cut profile tool in sections and any detailing tools to help alleviate the visual problem.

Hope this helps.

Josh

[tim.101799]

Use the join roof tool for the dormer problem. That will join the dormer roof to the face of the mainspan roof and get rid of the chunk of roof you are showing in your image.

As far as the split pitch, use a roof by extrusion. That will keep the roof as one and make this a smooth transition. Only problem is you don't have the convenience of a footprint roof with the pitch and wall association. But if you design isn't going to change much, then this should work fine. If you do stick with a footprint roof, just use the edit cut profile tool in sections and any detailing tools to help alleviate the visual problem.

Hope this helps.

Josh

For some reason the join roof toold has not been working to well for me, but I will give it another go. Also, I cannot model this roof by extrusion. It is actually a 4 sided hip

[ford347]

I made some pic for you, then I read your message about the hip. But I'll post them anyway. I've also posted a picture addressing the join tool. If I come up with something for the split pitch, I'll post it. Got to go to mtg. now though. Hope this helps some.

Josh

[ford347]

Here is a method to smooth out the split pitch using footprint roofs and an in-place family. Doesnt' take a lot of time and gets it looking good.

Josh

[tim.101799]

Here is a method to smooth out the split pitch using footprint roofs and an in-place family. Doesnt' take a lot of time and gets it looking good.

Josh

That is a pretty good solution, I will give it a try.

[tim.101799]

I made some pic for you, then I read your message about the hip. But I'll post them anyway. I've also posted a picture addressing the join tool. If I come up with something for the split pitch, I'll post it. Got to go to mtg. now though. Hope this helps some.

Josh

My problem is that to get the look I want I need to burry the dormer roof into the main roof. I want my gable to die right into the main roof. I don't want that little peice of eave / facia that you show.

So far the only way I can get it to work is to model my dormer roof like you show, then use an implace roof void to cut the dormer back.

[ford347]

My problem is that to get the look I want I need to burry the dormer roof into the main roof. I want my gable to die right into the main roof. I don't want that little peice of eave / facia that you show.

So far the only way I can get it to work is to model my dormer roof like you show, then use an implace roof void to cut the dormer back.

You can draw a footprint roof similar to the method used for a dutch gable. Draw a roof and use slope arrows to define the slope, then join roof geometry. Check out the pictures and see if that's what your after.

Josh

[tim.101799]

You can draw a footprint roof similar to the method used for a dutch gable. Draw a roof and use slope arrows to define the slope, then join roof geometry. Check out the pictures and see if that's what your after.

Josh

That is exactly what I am looking for, but when I previously tried the meathode you describe the join roofs command would not work.

[ford347]

You won't use the 'join roof' tool with this method, just 'join geometry'. Because you are drawing the shape of the roof in the sketch, so basically you are drawing the front face of the roof, then two lines at 45deg. representing the valley lines. Non of those lines are slope defining. You will then take a slope arrow from the valley and front line intersection and draw it to the center point of the front line, same on the other side and have those slope arrows be defined by slope. Then you have a roof in a triangle shape eliminating the need to join any face of this roof to another. You just need to join geometry, meaning join the dormer roof geom. to the main span roof geom. That's it.

Let me know if you have troubles with this.

Josh

[ford347]

Here is that dummy file I was using for the examples. This may help.

Josh

[tim.101799]

You won't use the 'join roof' tool with this method, just 'join geometry'. Because you are drawing the shape of the roof in the sketch, so basically you are drawing the front face of the roof, then two lines at 45deg. representing the valley lines. Non of those lines are slope defining. You will then take a slope arrow from the valley and front line intersection and draw it to the center point of the front line, same on the other side and have those slope arrows be defined by slope. Then you have a roof in a triangle shape eliminating the need to join any face of this roof to another. You just need to join geometry, meaning join the dormer roof geom. to the main span roof geom. That's it.

Let me know if you have troubles with this.

Josh


This meathod is what I originally used. The problem is that it onlt cleans up correctly if bith the main roof and the dormer are the same pitch. When the main roof has a lower pitch than the dormer (like in my model), the dormer geometry protrudes below the face of the main roof. It had the same results in your test model when I lowered the pitch of the main roof. So far I have been able to get it to work the way I want with a few work arounds. I modeled the dormer like the first way you showed using roof by extrusion, then I joined the roofs. From there I used in in-place void family to cut the dormer roof back to the correct location

[tim.101799]

one last question (for today). How do you model this condition

[bgauthier]

You will have to create a family or an in place family.

You should take a look at the DGCAD - Mastering Roofs videos. Very helpful.

[tim.101799]

You will have to create a family or an in place family.

You should take a look at the DGCAD - Mastering Roofs videos. Very helpful.

Where can I find those videos? Are they online for free, or something you have to purchase? It won't be a problem if I have to purchase them, the Principals at my firm are very commited to Revit and make sure we have all the resources we need

[bd04]

For the dormer could you use a roof by extrusion with the rafter cut set to two cut plumb and
the fascia depth set to 0.
Drag the fascia edge of the dormer roof to the intersecting point with the main roof and then use join roof.

[ford347]

For the dormer could you use a roof by extrusion with the rafter cut set to two cut plumb and
the fascia depth set to 0.
Drag the fascia edge of the dormer roof to the intersecting point with the main roof and then use join roof.

Hey, I like that. Good thinking! Thanks for sharing!

Josh

[bgauthier]

Where can I find those videos? Are they online for free, or something you have to purchase? It won't be a problem if I have to purchase them, the Principals at my firm are very commited to Revit and make sure we have all the resources we need

Check this site.
http://www.dgcad.com/

[Maximillian]

FYI

if you are using a different size lumber for your overhangs you may want to make model them as separate roofs. Not as hard as it sounds and it will be correct any way you slice it.