How to model a curved wall with arching top edge

[jhd]

I'm trying to model a wall that is curving in the x-y direction. In the z axis the two endpoints of the wall are higher than the midpoint. I've initially modeled the wall in rhino and brought it into a mass family as an .sat file. From there I load the file into my revit project and select the surface to make the wall. However, this process is not the most efficient workflow. I need to be able to make changes directly in the revit model without having to go back into rhino model, change the surface, re-export to my mass family and then re-create the wall. I understand that the conceptual massing tools can model the surface as well, but even that would be one step removed from where I need it to be. I'm linking together multiple models from multiple disciplines so I need to be able to make changes live in the model without bouncing between other surface modelers/families to make changes to a wall.

I've attached a sample model of the wall showing an imported .sat as well as an imported .dwg. The top edge can not be "attached" to anything, otherwise I could just model a basic extrusion and attach it to the surface above it. I want to be to think of this wall as a freestanding element with nothing attached to it. I've tried cutting wall openings, but it will only do rectalinear shapes. I've also attempted to make a massing family that consists only of a void geometry controlled by instance parameters, but that didn't really seem to work either. Although the void family approach is the direction I'm approaching this from in an effort to solve the problem. Any help on this is greatly appreciated.

[Munkholm]

Jhd.

How about an in-place mass, and then turn it into a wall by the "model by face" tool ?
It´s easy to model the mass, and if you change the mass, you can just use the "update by face" tool :beer:

The attached is done entirely whitin the project - Meaning, no Rhino and no Conceptual Masses...

[Dimitri Harvalias]

In addition to Munkholm's suggestion (probably the best/simplest approach)...

The top edge can not be "attached" to anything, otherwise I could just model a basic extrusion and attach it to the surface above it.
You can create a roof by extrusion, attach the wall to the roof and then turn the roof off in the view (or place it in a separate workset)


I've tried cutting wall openings, but it will only do rectalinear shapes. .
You can't edit the profile of a curved wall but if you create an in-place void (wall category) and cut the void from the basic wall you will be able to carve the shape you have here.


Although the void family approach is the direction I'm approaching this from in an effort to solve the problem.
Should be able to do this with a face based family. Unless you do this type of construction all the time the time it takes to set this up to be fully parametric may not be worth the trouble IMHO.

[twiceroadsfool]

I would do it with an in-place Void of the wall catagory, and ill tell you why:

Geometrically, there are two ways to accomplish what youre describing:

1. The arc for the top of the wall drawn in a flat elevation, and then projected back through the curved (plan) wall.

2. The arc for the top of the wall being dictated by a consistant change in elevation along the top of the wall, as it projects around a certain number of degrees in Plan. (IE: 6" in height per 10 degrees.)

The differences are pretty far reaching. If you go with number 1, the TOP of the wall will not always be horizontal (the top piece of drywall (or whatever) will be twisting as it follows the top of the wall. It will also only be horizontal at the center point of the wall. It will be tapering elsewhere. In addition, the "rate of elevation change" along the curved wall will vary, depending on the "angle" compared to the plane that the arc top is drawn in. The wall will "look right" only from the front elevation.

Number 2 will have a flat top to the arc wall at all points, but that flat top will vary in height consistantly as it progresses around the circle. "Technically" this means a minor ridgle line at the high point of the circle, though the contractor would more than likely round it off to be smooth.

If Number one is what you want: Component: Create in place: Wall Catagory: Void : Extrusion. WP = anything flat across the chord of the arc wall in plan. Draw the arc, lop off the top of the wall, and stretch it to the extents of the wall.

If number two is wat you want: Component: Create in place: Wall Catagory: Void: Swept Blend. Path = line of wall in plan, for only half of the wall. Profile 1= one end of wall, a shape to cut off the amount above the end of the walls height, Profile 2 = at the center of the arc, shape to cut away the wall above the highest point. Then, mirror that swept blend to the other half of the arc wall.

I just went through this design iteration in house the other night... If i remember ill post the files tomorrow. I am realizing that a lot of designers seem to think they want number one,and im not sure if they realize they get number 2 when it gets built, lol... I think they think they want number one, but number two makes more sense (in my humble useless opinion.)
2.

[Dimitri Harvalias]

(in my humble useless opinion.)

Feelin' down buddy :( Don't be so hard on yourself. ;)
Good explanation and valid arguments. I agree the void family would probably give the greatest control over exactly how the top of the wall is shaped.

[twiceroadsfool]

Feelin' down buddy :( Don't be so hard on yourself. ;)
Good explanation and valid arguments. I agree the void family would probably give the greatest control over exactly how the top of the wall is shaped.

LOL, its been a long week. I tow a careful line between wanting to work with the designers, and wanting to work with the production staff. The beauty of Revit, i tell them, is issues like the two options listed above.

Now, i wont make the basless generalizations that are rampant in our industry, but *its been my experience* that a MINOR issue like this can actually go completely unresolved, without a building model. They draw the arc top in elevation (straight on) and they draw a section (where the top is flat). They miss- however- that both of those arent actually possible together.

The first time i had to put this exact situation in Revit, and DOCUMENT it for construction, it brought this issue up to me. So now, i answer the "how do you do it in revit," with the "how do you do it for real?"

But yeah, its been a long week....

[Munkholm]

If number two is wat you want: Component: Create in place: Wall Catagory: Void: Swept Blend. Path = line of wall in plan, for only half of the wall. Profile 1= one end of wall, a shape to cut off the amount above the end of the walls height, Profile 2 = at the center of the arc, shape to cut away the wall above the highest point. Then, mirror that swept blend to the other half of the arc wall.

Aaron.

That was also my first thought, but when I did a quick testing, it turned at that the shape would be "V-Shaped" - See the attached....

The best (only ?) way to accomplish this, (if the top of the wall should be horizontal at all times) is by the in-place mass, which can be modelled from the 6 lines, shown in the attached image... :beer:

[twiceroadsfool]

Aaron.

That was also my first thought, but when I did a quick testing, it turned at that the shape would be "V-Shaped" - See the attached....

The best (only ?) way to accomplish this, (if the top of the wall should be horizontal at all times) is by the in-place mass, which can be modelled from the 6 lines, shown in the attached image... :beer:

No, what i was saying is draw a regular wall, and then cut the top OFF with the Void Extrusion or a Void Swept Blend. And as i mentioned, where you are getting the "peak" there will be a ridge line from the two void swept blends. But mathimatically, thats correct...

You CAN do it that way, making the wall and using a swept blend void on top. I have one on my computer done that way...

[Munkholm]

In that case, I must be doing something very wrong here... whatever I do with the mirrored swept blends, it turns out as a "V-shape"... What´s the secret ?

[Scott Womack]

In that case, I must be doing something very wrong here... whatever I do with the mirrored swept blends, it turns out as a "V-shape"... What´s the secret ?

Are you creating the "void" in an elevational view as an extrusion? If not, create a reverence plane as a "cord" of the curved wall, and name the reference plane. Go to the closest elevation view, and then create the in-place void as an extrusion. When it asks for a "plane" give it the named reference plane. Now draw the void using a curved "bottom", and make sure the curve extends beyond the end points of the wall.
file:///C:/DOCUME%7E1/srw409/LOCALS%7E1/Temp/moz-screenshot.png

[Munkholm]

Scott.

That sollution is not making the top of the wall "perpendicular" to the face of the curved wall... or am I just totally lost here... :confused:


2. The arc for the top of the wall being dictated by a consistant change in elevation along the top of the wall, as it projects around a certain number of degrees in Plan. (IE: 6" in height per 10 degrees.)

[Scott Womack]

That sollution is not making the top of the wall "perpendicular" to the face of the curved wall... or am I just totally lost here... :confused::Oops:

Klaus,

Welllll, my math is not good enough to confirm that, so it may not be. You could probably get closer by using a revolved"cone" using a combination of the reference plane at the cord, and a radial line perpendicular to that plane. You'd have to do some serious math to figure out the appropriate radii of the truncated cone, but I believe you could get there. This is one for "Count Formula" (David Baldacchino) to weigh in on. My guess is he could do it.

Personally, I'd get it close, then detail it, calling for the top to be perpendicular.
:roll:

[twiceroadsfool]

Scott.

That sollution is not making the top of the wall "perpendicular" to the face of the curved wall... or am I just totally lost here... :confused:

Right, thats what i was saying. If you "pull a void cut" front to back, it cant/wont give it a perpendicular and flat top.

Using the void swept-blends,it will look like it has a ridge in the center, but in reality the contrator will just smooth it out there. The onlt way to diminish that is to make it several swept blends with decreasing rates fo change around the arc.

But the real issue is the "speed" at which the curved walls height changes, and thats what i was trying to impose. The blend method gives you a consistant change around the arc, which i think is what people are after many times. (Now that i see the picture, in this case youre changing from swinging down to swinging up, which means the direction of the blend is changing. I would use three or four blends to gradually change that rate).

But if you take MULTIPLE elevations, going around a circle using both of these methods, the extrusion void only looks right when youre looking in the direction of the work plane. The perpendicular direction is strange. The consistant swept-blend looks more correct in all elevations and sections, it just *shows* the ridge that will never get built.

But for me, its also in detailing. The guy in the field isnt going to built a 12 foot wall and then cut it down with a laser from the front. The void extrusion method not only begets you a CONSTANTLY variable angle of the top of the wall, but it also yields you a constantly changing rate of wall height, meaning if you spot elevation the wall every 12 or 16" (say, for stud heights), there will be no consistant rate of change. The blend method is basically saying "Height drops 4" every 10 degrees of the arc," etc.

Its splitting hairs, to be sure. And if i hear "The contractor wont care," from anyone here im throwing my mouse. Mies said God was in the details, and my exes father said the Devil was in my closet. Well, somewhere in there is a penchant for modeling correctly, EVEN IF the contractor will leave the drawings in the truck on monday. :)

[sthedens]

The guy in the field isnt going to built a 12 foot wall and then cut it down with a laser from the front.

No. But wouldn't that be too cool!



And if i hear "The contractor wont care," from anyone here im throwing my mouse.

The contractor won't care. ;)

Great thread, lot's of good ideas.

[mthurnauer]

In fact, both methods are buildable if you accept that with option #2 that the contractor is going to place the studs properly in the track giving you a top surface that is perpendicular to the exterior face of wall. But to document that the top of wall is to be a certain radius at a datum line perpendicular to the midpoint of the wall is practical. The question is just what do you want? Option one is simply a helix and option 2 is an arch tangent to the radius.

[Munkholm]

Welllll, my math is not good enough to confirm that, so it may not be. You could probably get closer by using a revolved"cone" using a combination of the reference plane at the cord, and a radial line perpendicular to that plane. You'd have to do some serious math to figure out the appropriate radii of the truncated cone, but I believe you could get there. This is one for "Count Formula" (David Baldacchino) to weigh in on. My guess is he could do it.

Personally, I'd get it close, then detail it, calling for the top to be perpendicular.


Scott.
I´m no mathematical genius either, but that´s not really the point here. We´re talking about two very diferent shapes, and both of them CAN be modeled (and build).
#1 use void(s) to cut the curved wall horizontal
#2 make a mass to get top perpendicular to the face


Its splitting hairs, to be sure. And if i hear "The contractor wont care," from anyone here im throwing my mouse. Mies said God was in the details, and my exes father said the Devil was in my closet. Well, somewhere in there is a penchant for modeling correctly, EVEN IF the contractor will leave the drawings in the truck on monday.

AMEN ! But Splitting hairs, maybe - but if you want option #2, I don´t see any reason to model it as option #1, and show it like that in elevations etc.
I´m doing a lot of teaching these days, and also love to show of, with the conceptual massing tool, but always ends the "show of" with: "OK, Cool - We can model it with these tools... but can YOU document it for the costrucors to build ?)



In fact, both methods are buildable if you accept that with option #2 that the contractor is going to place the studs properly in the track giving you a top surface that is perpendicular to the exterior face of wall. But to document that the top of wall is to be a certain radius at a datum line perpendicular to the midpoint of the wall is practical. The question is just what do you want? Option one is simply a helix and option 2 is an arch tangent to the radius.

My words excactly ! :beer:

[twiceroadsfool]

Both versions are buildable... yes. Except number 1 means a "top of wall" (drywall?) that is rotating in plan, sloping down as it progresses, and twisting while it goes. Feasible... yes. I would (genuinely) like to see some photographs of a finished product where they did it, however. Im sure theyve done it plenty of times, i just think it must be... interesting. :)

[twiceroadsfool]

Scott.
I´m no mathematical genius either, but that´s not really the point here. We´re talking about two very diferent shapes, and both of them CAN be modeled (and build).
#1 use void(s) to cut the curved wall horizontal
#2 make a mass to get top perpendicular to the face


You can use a void to get at number 2 as well, its just not a void Extrusion. ;)

[Munkholm]

You can use a void to get at number 2 as well, its just not a void Extrusion. ;)

Arrrggghhh....

Aaron, if you are serious ? Please enlighten me on this one ! I swear that I´ve tried everything with the "Mirrored swept blends"
But it turns out "V-Shaped" what ever I do whith that aproach :shock:

I´ve attacehd my testings... If I´m wrong, PLEASE enlightnen me ! :beer:

[Munkholm]

Uups.. forgot the attachment.. sorry.

[ajtrahan]

I would like to know how to model this wall using the mass tool. My preference would be to draw the curve in plan view and extrude then open an elevation and add a void. Then select the mass and create a wall from it. This seams the easiest way. I am not familiar with reference lines and trying to adjust the 3D points or doing the void in plan. It is so easy to model in AutoCAD....

Can you direct me to a tutorial that explains how to do this?

Thanks,
Jason

[cliff collins]

I've attached an example.

From the imported geometry, I created an in-place Mass, and used reference lines, reference points and splines thru points to create Form ( face, not solid )

Then simply click on the mass face to make a Wall.

The whole thing took about 5 minutes. No voids and confusing geometry needed.

cheers

[ajtrahan]

Thanks Cliff! I now understand.

Jason