Is there a way to define ref plane by 3 points in space?

[Gadget Man]

HEEEELP!

Hi,

I was wandering if there is a way to define a reference plane by specifying 3 points in the space - like I used to do all the time in AutoCAD?

I have this blasted roof that doesn't follow any reasonable angle (or I can't find it...).

It is now 12.50 am (in the morning) and I still try to solve it...! The problem is, that the front of veranda is not parallel to the corresponding wall (see picture 1), so the roof panel is of some odd shape. Unfortunately it has to match the roofs on both sides and also at the fascia as well as at the wall..(of course!). I guess I can't do it in one piece - fortunately there is a dormer to conceal any roof discrepancy, but I still have to model it and I have no obvious roof pitch that i know of to follow..! (See picture 2). "Three point" reference plane would be perfect - I simple would click on both wall-ends and a fascia point and - bingo! But I don't know how to do it in REVIT. HEEEELP!

Jerry.

[sjsl]

Have you tried making the main part of the roof and then putting the gable on it and then using the Modeling/Opening Tool/ Open Placement Options Dialog box/ select : Pick a roof, floor or ceiling to cut vertically....to remove the area under the gable? You can create a shape with this tool as required. Work in plan view.

[aaronrumple]

3 points not needed. This is simple.
Make the plane as if the dormer isn't there with a footprint roof.
Cut a hole in the roof using the opening tool.
This can all be done in plan. See attached.

[Scott D Davis]

How about this:

Model the odd shaped roof piece without the dormer, using the roof tool, but use a slope arrow instead of a slope defining line. Place the slope arrow on one 'edge' of the roof, tail at the fascia, and head of the arrow at the top. After you get that piece, then construct the dormer. (let it overlap the first roof). Then use the Opening tool on the modeling bar, and select "Cut dormer opening". Follw the instructions for picking the roof on the 'status' bar (lower left of the Revit window). This 'should' work for what you are trying.


(edit: Aaron beat me to it, AND provided a RVT!)

[bclarch]

This is similar to a problem that I had that lead to one of my first posts on the ZoogDesign forum. It even involved a green standing seam roof. Chris Mahoney, one of the Revit client support architects, responded with a mathematical approach. I went to the ZoogDesign forum to try and find the thread but was unsuccessful.

This is the theory a best as I can remember. You need to sketch the roof boundaries and use a slope arrow to manipulate the orientation. Essentially what you need to do is determine the change in height over the length of the roof and use this as the z component for the slope arrow. I wasn't able to get it to work by relying on math alone. I remember tweaking the angle of the slope arrow as well as it's head and tail height a number of times until I got a close enough approximation.

[aaronrumple]

No need to be inexact using slope lines. The trick in using slope arrows is to get the arrow pointing the right direction. In this case perpendicular to the eave of the roof. You'll see these two triangular section line up perfectly - all done in plan.

[cmahoney]

I think this is the FAQ Robert refers to:

How can a planar roof be created when all that is known is the elevation at the vertices? (http://revit.autodesk.com/pillar/custserv/web/service/support_4.0/faq/Roof/10_roof.asp)

[bclarch]

The trick in using slope arrows is to get the arrow pointing the right direction.
Agreed. However, in my case the slope wasn't perpendicular to any of the model geometry nor parallel to any of the edges of the roof so it took some tweaking to find the right angle.

Chris,
Thanks for digging that up. Does Revit still assign Client Service Architects to individual firms or is that practice long gone? I thought that that was a good way to make firms feel more comfortable about making the transition.

[Gadget Man]

Thanks to All!

I think that BCLARCH was the one that described my situation precisely. The method of generating this piece of roof as one and cutting a dormer later is obvious, but it (obviously again) generates a roof that doesn't cut the wall at one level (because fascia is not parallel to the wall..!). What I tried to describe was the situation, where all three main veranda roofs are not only aligned at the fascia, but at the wall too (that's not possible mathematically, I know, but any visual approximation would be good - with dormer breaking the pattern - that's why I wanted to make this part of the roof from 2 pieces - they WOULDN'T align to each other at the wall, but then cut the dormer opening in them obscuring any discrepancy).

What I don't know is what angle (roof pitch) and at what angle from the fascia should those 2 pieces be created at. If you want to do it this simple way, it translates to creation of, say, 2 different reference planes (each for one part of the roof) for simply "cutting off" a mass by the void and then creating a roof by face...!

And for that reason it would be extremely handy to have 3-point plane creation tool: ONE -> Fascia of the right main roof , TWO -> "wall end" of a left roof, THREE -> "wall end" of a right roof - PRESTO..!

Then for the second roof: ONE -> Fascia of the left main roof, TWO -> Fascia of the right main roof, THREE -> "wall end" of the left main roof - DONE..!

No need to calculate (or know) any angle, distance - nothing! It is so simple in AutoCAD...

Don't get me wrong! I DO appreciate your answers (and so quick too!) - they gave me an idea anyway... I will make the left main veranda roof a little steeper than the right one, so my created "middle", "diagonal" piece will align both left and right roofs back and front.

However, it would be nice to have three-point plane anyway...

Jerry.