General Roof Advice

[Anonymous]

At first I had been doing my roofs by setting the "roof thickness" parameter to the size of my rafter. That was fine for awhile while I was first learning but it aways bugged me that this made my fascia too tall.

Now that I'm starting to work on making my sections and other things more accurate I've started setting that parameter to the sheathing thickness then using the roof wizard to add rafters. The first problem I come across with this method is that the rafters get placed on top of the roof. I can change the elevation of one or the other and make it look right, but that's kind of a pain. I was wondering if there is something I'm missing to make the rafters go below the roof. Also, in general, how do y'all work with roofs.

Thanks,
Rick

[David Maudlin]

Rick:

I set the roof thickness to rafter + sheathing + roofing (+ gwb if cathedral ceiling), then place a slab for the exterior soffit, and use SEO to get the correct eave profile. The location and height of the roof reference line is important for knowing the rafters are at the correct height. I will then add lines and 2D parts (2x lumber, batt insulation, etc.) for my construction sections on top of the model. This is a simple approach, I know others on this forum will model each part as you described, depends on how you want the model to approximate construction, and how it helps with the documentation.

HTH,

David

[Anonymous]

I've been avoiding SEO's because they never seem to do what I think they will and it doesn't seem you can undo them.

[Anonymous]

Wrathchild
SEO's are easy to undo.
It's trim to roof that you might be thinking of.
I actually make two seo layers and put the C.P. "operator"
on one of those layers so I can turn it off, you most likely will want to do that. The other seo layer is in case I have an operator I don't want off for whatever reason, you should not need more than one seo layer.
Effect stays unless you move "cutting" seo operator, or delete it.
Bier
ps
One of the neat things about seo's, for roof rafter tails is you can have several styles you like pre-made, with Custom Profiler. Somewhere on this forum there is an article describing how to use the same C.P. as an seo template style and just rotate it
for the different pitches. Very handy indeed!

The basics are; in your C.P. make and leave different lines (they don't show) that represent the different pitches and just change the "Construction" part to that pre-made line pitch. Do that for each rafter tail shape you want.
I have trouble finding things with searches on this forum, but if I find it, I'll make a link.

[Anonymous]

This is an interesting one,

I personally, and i think it is our office standard, to set the roof to the thickness of the finish, i.e if it's slate, set to about 15 - 20 mm, or if it is single ply membrane, then normally set it to the thickness of the insulation 100 mm etc.

Then the rafters i use the standard ArchiCAD roof construction library parts, set one and distribute out. But then our existing building models are always done as much as possible in 3D, and as detailed as possible, so this obviously may not be the best way to do things.

If the project were only going to say the planning stage, then i would probably set the thickness to the size of the fascia, but if you do that it can prove a bit more difficult later on when you come to detailing etc.

I am interested to see how other people do this, so keep em coming!

[gpowless]

I use composite roof slabs and then add rafters or trusses using the roof tool or the truss maker tool. I sometimes forget that just because we can dimension and model with an accuracy of 1/64" (or 1mm) that doesn't mean that builders construct to that accuracy.

General sections are presented usually at 1/4" (1:50) and at that scale it is difficult to tell whether or not there is a composite roof slab or individuals construction layers in the section. As with manual drafting, line weight stills plays a much more important part than does individual built-up parts.

[Anonymous]

Bier wrote:
Wrathchild
SEO's are easy to undo.
It's trim to roof that you might be thinking of.
I actually make two seo layers and put the C.P. "operator"
on one of those layers so I can turn it off, you most likely will want to do that. The other seo layer is in case I have an operator I don't want off for whatever reason, you should not need more than one seo layer.
Effect stays unless you move "cutting" seo operator, or delete it.
Bier
ps
One of the neat things about seo's, for roof rafter tails is you can have several styles you like pre-made, with Custom Profiler. Somewhere on this forum there is an article describing how to use the same C.P. as an seo template style and just rotate it
for the different pitches. Very handy indeed!

I'll see if I can search that out and take a look.

The basics are; in your C.P. make and leave different lines (they don't show) that represent the different pitches and just change the "Construction" part to that pre-made line pitch. Do that for each rafter tail shape you want.
I have trouble finding things with searches on this forum, but if I find it, I'll make a link.

[Anonymous]

I can undo trim to roof easily enough, but I'm still having trouble undoing SEO's.

[Anonymous]

Hi Wrathchild
Did you put the SEO's operator on a separate dedicated Seo layer?
If so, you can just turn off that layer, effect will go away, but if you
want "operator's" effect to go away permanently, just delete the operator
or move it off to the side.
Now as I think through this, maybe you used a part of your building as operator, (and don't want to delete it), in that case, look at the bottom of the SEO dialog box.
There are options for canceling the effects of operators and or targets,
or both.
Notice it says "selected".
That should do it.

Bier

[Anonymous]

Thanks Bier,

You are correct that they are parts of my building that I didn't want to delete.

I have seen the options at the bottom of the SEO window but I don't think I've ever tried to use them right after performing an SEO that didn't work right for for me. I'll try being more careful next time and see how that works for me.

For now, I guess the only thing I can do is delete parts that didn't SEO right and start again. Not so bad since I haven't messed up to much trying SEO's and I have been having a little more success with them lately. They're pretty cool once you get the hang of them.

Don't forget to let me know if you run across the post about the rafter tails again. I haven't been able to find it either.

Rick