Well the Truth is you can't. Be nice to be able to wouldn't it!
UPDATE: Best practise shown in my video on youtube here.
Whole Roof Object Playlist here.
But I can get you close enough to get the job done in an efficient manner without resorting to slabs.
Here I'm going to show you how to create....
Dormer Roofs (ok this is another Sergej tip and he keeps telling me I have to share this one) but this technique could be used for adding any hole.
We start with our roof sketched out using the roof object. We add our dormers, and it looks great on the sketch & 3D but now we are onto working drawings and we want to subtract the holes to do sections and interior shots. Ulp! Do we explode to aecSlabs NOooooooooooo!
Here's what I would do :
Note 1; Odin has pointed out to me that you don't need to start with an ME. Using the command MassElementConvert (or just type MassElement and use the C option) you can turn a roof odject and many other objects into an ME. I tried it with a mess of aec objects and solids and it worked with them all. If you have shapes that are part of your roof that are not suited to a RO or even slab, then feel free to use any object required. He also emphasises that using the model explorer will allow you to edit more freely later whereas my approach means to edit is to basically delete or keep the original elements to remake your shape. You then have to freeze or export the objects for safekeeping but the brilliance of the MODELEXPLORER is it keeps all the objects hidden away unless you need to access them.
OLD SCHOOL NOTICE: Subsequent to Odin's helpful tip this is not the preferred method although it will work. The Best approach (See Odin's note) is to use MODELEXPLORER as it retains all the parts of your roof and you can edit later.
Create a small MassElement (ME) (*see note 1 below) on your roof layer in one corner in a style defined as 'Roof'. This should be completely inside the roof object (It's going to disappear). Next we create ME objects to use as subtractives for the dormer holes that would be cut out of the main roof. These have no need of any style. (*1 After we've finished maybe put these items with your main roof object onto a non-print layer to be frozen later or WBLOCK them out as a separate drawing (out the way) as you may want to go back and edit the roof.)
Select your 1st ME, right click and add (union) the roof object to the ME using the Boolean functions and then also Subtract the dormer hole objects the same way. No need to add the dormer roofs as they can stay separate roof objects (unless you want to!). Done! You can add the roof material to your roof ME style the same as the RO's.
*1 Keeping the original roof object and negatives allows you to make adustments later if required. Reposition and recut holes.
You know this is a great trick and the funny thing is that Odin Cary showed us all years ago in this page in his instruction set. I did read it but didn't understand the potential. This method improved and simplified in the next release after he wrote his article and I show here how simple it has become.
Tip: When creating the dormer roofs here I made a square roof and gave the back edge a 145d pitch (180d - 35d (my roof pitch) to get the dormer to run into the roof. However the Roof Object will give you am unwanted face on the inside and also square off the overhang where it meets the roof and I had tricks to work around this - WRONG WAY. Duh! Create a 5 sided object with the back 2 edges at 90d to nestle into the roof. Simple & done.
And that's the hole truth.
.Cheers
