3d sweep curved path for fascia? eyebrow roof? images inside.

[3dway]

I've been posting about my roof with a curved flare. The soffit ends, where the curved flare is more or less cut through in section, I need the fascia trim to follow the roof curve.

I have a workaround for the soffit end.


I also have an eyebrow roof with a straight edge at the side, and a the eyebrow curve on the front. I need to put a fasia all around this and I can get a 3d path for the sweep by using "pick path" but it bends the profile at the side. If I locate the profile on the side of the path it bends the front. I assume that this is to get it to mitre at the corner.

Anyone have a solution for this?
Here's 3000 words:

[3dway]

If you look at the elevation of the eyebrow fascia, you see the extra line from the bend in the profile.

It almost looks right in 3d (its an axo view, what I would call user view in max)

The last image is the workaround for the soffit end at the flare. I build an in place family with includes the corner of the fascia trim.

[patricks]

So you want your trim to be vertically oriented along the eyebrow curve, but you also want the trim to be vertical at the ends where it turns back into the main roof, correct?

The problem with that is that it would never miter correctly even in real life. If your trim is vertically oriented along the curve, that means the profile follows the curve perpendicular to the arc (parallel to the radius). If you cut a vertical section through that portion, you will find that the profile height is longer than the actual profile shape, since the section is essentially cutting the eyebrow trim at an angle with respect to the radius (unless you cut the section at the very center highest point of the curve).

So when the profile gets to the corner, the vertical height of the profile is different than the actual profile height around the sides, and so it won't behave like you think it should.

To get a better picture of what I mean, model a simple roof with 2 sides sloping, and the 2 ends as gables. Now apply a roof fascia to one of the lower eaves, and then pick one of the gable rake edges to continue the fascia. You'll see that the fascia has to continue horizontally around the corner for a short distance and then angle up with the rake. This is necessary to get the proper mitering.

As far a fix, the only thing I can think of is use 2 different profiles, one for the sides and one for the actual eyebrow arch. That's probably how it would be done in the field anyway. The arch trim would be put in place first, then the carpenter would measure the vertical height of the trim at the ends and then rip boards for the sides to match up properly at the corners.

[3dway]

Actually, perpendicular to the curve on the sides would be fine as well (square cut).

I see what you're saying. On the soffit end for the curved flare, you see the trim piece cut horizontally after it turns the corner but before it curves up.... or the curve cuts off with a little flat bit if you prefer to think relative to the curved trim.