Sloped Roof Members

[david_peterson]

Lets say I wanted to slope my roof structure and have a constant thickness to my insulation as opposed to tapered. Where do I have the start and end hight, I can only find an elevation. How do you accomplish one of the most simplistic aspects of a roof. I know that some engineers may not even consider 1/4" per foot slope in the analysis, but there should be an option. Maybe I'm missing something here. Do I need to create separate families that allow for sloped framing. I'd like to see something that says start of beam elevation, end of beam elevation and maybe a check box for flat, and the elevation input that exists now.
Thanks in advance.

[david.kingham]

There are 2 options right now. First is to draw the beam sloped, this will put the beam on a reference plane and you can rotate the reference plane. Second option is pick the plane of the roof first, then draw your beam on that plane, if you use this method your beams will change if you change the pitch of your roof. If you have beams drawn flat allready you are screwed. There is no way to rotate them, you will have to redraw them all :( I learned this the hard way

[James.Lupton]

There is a way to do this.

If you have drawn the beams horizontal, first draw a horizontal reference plane and give it a name

then select the beams in question and change their reference plane to this new plane.

Once the beams are in this plane, change the slope of this plane to the new slope required and the beams will follow.

It usually takes a few goes to get the rotation correct since the rotated plane is not always going to land on the exact sloping plane required.

[blads]

There is a way to do this.

If you have drawn the beams horizontal, first draw a horizontal reference plane and give it a name

then select the beams in question and change their reference plane to this new plane.

Once the beams are in this plane, change the slope of this plane to the new slope required and the beams will follow.

It usually takes a few goes to get the rotation correct since the rotated plane is not always going to land on the exact sloping plane required.
Great Tip...thanks James

[david_peterson]

There is a way to do this.

If you have drawn the beams horizontal, first draw a horizontal reference plane and give it a name

then select the beams in question and change their reference plane to this new plane.

Once the beams are in this plane, change the slope of this plane to the new slope required and the beams will follow.

It usually takes a few goes to get the rotation correct since the rotated plane is not always going to land on the exact sloping plane required.Thanks for the tip, I guess I'm also wondering if you can do this using levels. I have a cmu load bearing structure and we will be change the bearing point elevations to slop the roof. Knowing that I need to call these out (and being new to the program) is there a way to create a family that had a start elevations at one level and an end elevation at another. Maybe say like a brace, but be able to change the beam type to gravity type framing?
Thanks.

[david.kingham]

Very nice tip James, I asked the same question months ago and never got a good answer like that!

[cholmes]

I was wondering if there was an easier way to do this as well. The way I typically work, in ADT for example, is that I know what the elevations of my beams are supposed to be at, so I will set the columns to be that height. Then it's just a matter of snappiing to the tops of each column, and I get the correct slope or elevation. For example, I will have a run of beams at 15', a run at 15'-6", and a run at 16'-0", with sloping joists between them. I find it difficult it Revit to accomplish this. I am still in the experimental/ evaluation stages with Revit, but this seems like it should be a simple thing to do.

[david_peterson]

I was wondering if there was an easier way to do this as well. The way I typically work, in ADT for example, is that I know what the elevations of my beams are supposed to be at, so I will set the columns to be that height. Then it's just a matter of snappiing to the tops of each column, and I get the correct slope or elevation. For example, I will have a run of beams at 15', a run at 15'-6", and a run at 16'-0", with sloping joists between them. I find it difficult it Revit to accomplish this. I am still in the experimental/ evaluation stages with Revit, but this seems like it should be a simple thing to do.My thoughts exactly. I just got done pulling half my hair out with ADT. I'll be bald by the time I get done with this whole BIM thing.

[KMGuillotte]

I have encountered similar conditions as the rest of you. I know (at the current moment) that RS can't slope a whole floor level, or specify a slope from one level to another.
From my discussions w/ Autodesk RS development, the best way to frame this situation is to create a reference plane (giving a name is optional, but recommended) in section along the slope that you need and place your framing. It is best to have one edge of your reference plane start at a floor level. At that indicated floor level is where you apply your slab (horizontally) and then apply your slope. This was a shock to me as there is no way to have your slab and your framing parametricly (sp?) connected to each other. You can't apply a slab to a sloped plane...you can't apply your slab to the same plane as the beams were applied. If one of them change you will need to go and change the other manually. This however I found was incorrect...
What I did find, however, is to layout your slab first (as mentioned above), slope it, and then use your slab as your reference plane to layout your framing. If your slab changes slope then your framing will follow it. It is backwards thinking w/ respect to the order you would build it (slab first, beams supporting it second), but it works.

One thing to be cognizant of is to remember that your analytical plane will be the horizontal plane in the floor you created the slab. If you have sloped framing and level framing where you need to have a beam sloping to support a ramped slab and another beam to support an elevated slab...you may get conflict or an error when exporting to analysis programs, because the analytical model will see 2-beams occupying the same space (the horizonal plane). (see attached ramp elevation: Level beam supports slab beyond, slope beam supports ramp near side).

Autodesk is familiar with the above situations and will try to address it in the coming releases.

[James.Lupton]

I have encountered similar conditions as the rest of you. I know (at the current moment) that RS can't slope a whole floor level, or specify a slope from one level to another.
This was a shock to me as there is no way to have your slab and your framing parametricly (sp?) connected to each other. You can't apply a slab to a sloped plane...you can't apply your slab to the same plane as the beams were applied. If one of them change you will need to go and change the other manually.

............................

Autodesk is familiar with the above situations and will try to address it in the coming releases.

It is great to see these issues finally being brought to light. We have been using Revit for Structural work since Version 3.0 and have for a long time been trying to explain the need to define structural components on any plane not just plans, sections and elevations.

I would also like to see a solution where a curve or even an ellipse will be the reference surface to which members are aligned but lets walk before we run.

We should be able to use al the functionality of level based components whilst working in any plane. a change in the position of the plane should act in the same way as a change in the level of a floor. in addition, any change in the slope should be reflected by a change to all elements defined in that slope.

It is often the case that roof slopes change during the development of the design however, such a change at present can be time consuming in Revit particularly where there are diagonal members such as roof bracing.

I would like to see the option to maintain the plan position when rotating a roof or floor defined on a sloping plane. By this I mean that when for example the slope of the roof changes, the node points will move in plan under pure rotation. On many occasions we would want the node points to move vertically to the intersection with the new position of the rotated plane.

elements such as roof bracing often align to vertical columns and need to keep the alignment in plan.

It is also possible that the rotation of a plane may require sloping dimensions to be maintained and not the plan position. For this reason both options need to be catered for.

I understand the point you are making on the analysis side however, the most important issue is to allow the model of the physical geometry to be defined.

[david.kingham]

I've allready submitted this request to Nicolas Mangon but I'll post it here too for sh!ts and giggles.

Creating warped roof systems is extremely difficult, you have to manually rotate each joist/beam into place and then create a blend for the roof. First we need the ability to just input an elevation for each end of the beam, secondly we need a beam system that can have an elevation at each corner to create a warped system.

Here's my example

[James.Lupton]

David

I think what we are all saying here is that we need to be able to define objects where the position of the object is determined based on a surface shape rather than a definitive plane.

Curved roofs are quite common and are difficult to create in Revit. If the radius of curvature changes during the design development stages this becomes a nightmare to redefine the roof.

The current solution to this would be to use in-place families extruded to the curved shape however, this defeats the purpose of the BIM and can not be transfered on to third parties such as steel fabricators.