Developed Moulding

For all the architectural types here:
Cornice mldg. runs along an eave, turns 90%%d, and angles up the gable rake. This requires two
different profiles to miter together correctly.

My question: How do you generate the rake profile from the cornice profile, given the roof pitch.
The old school way...ie board techniques. I need this to be and instructional tool for 2d CAD
draftsmen. Web searches have turned up zip, zero, and nada.

TIA for the input.

 

Post up a 2D and I'll look at it, I still teach OLD school drawing.

Nick

 

I'm unsure what the drawing layout is. If you gave me an orthographic
view(s) of the
profile I would extrude it along the 30degs path and get the dimensions for
you.

The path for the extrude would be along the lines then turn thru the 30degs
corner then down.

So I need the profile then the path.

Does that make sense ?

Nick

 

PS A photo of a similar moulding installed on an actual roof
would help me understand it.

Nick

 

Nick;
I'll get back to ya.
I'm shootin' blanks on it at the moment and am temporarily swamped.
Monday, ya know....

 

Make you cornice molding (or moulding, if you prefer) into a 3D solid first.

To properly display a cornice molding, you should approach it the same way as if your were installing the real thing.

Extruding along a path might work if the path is a 3D polyline. Otherwise, the old fashioned way will work.

Place your moulding solid along the eave side leaving enough past the end (corner) to miter.

Place another molding solid at 90 degrees and aloign with the first one with an overlap past the corner.

Slice the two solids to create a miter at the corner. Throw away the trimmed off pieces.

(The above two steps could also be done by extruding the cornice profile along a polyline path which turns the corner.)

Place a third molding soild aligned with the gable end roof pitch overlapping the turned corner molding.

Slice the angled and turned corner solids. Throw away the trimmed pieces.
Do the same thing at the peak goinf down the other slope side of the roof.

Once you get the shapes you want in the positions you want, you can copy to other locations where they will fit OR: make them into a block and insert them. (Recommended)


Message was edited by: teiarch

 

I just ran into this in an old carpentry textbook from the early 1920's. If you are still interested I will send you the answer to your problem. It is a geometric problem, when you see it layed out the way old craftsman layed it out you will see the common sense behind the whole thing.

PeterK

 

Thanks Peter.
I just sent you an email.