Structural Columns

[Batman]

When placing structural columns on a building level they seem to default to the lower level as the base instead of the current level/plan.

Is there a setting to allow change of this before placement of the structural column?

[sbrown]

Structural columns behave this way because thats typically how struct. engineers place their columns, from the top down. I know of no way to change this behavior, except use architectural columns. I usually set up a copy of my plans for structural and set the view properties discipline to struct. and make sure that when I place them I can see them so i can select and change them.

[Tom Weir]

I've been doing structural drawings for a long time and I never place them from the top down. If I am modeling a building I sure don't start from the roof. I think the Revit structural team got it wrong and should correct it.

Maybe that's the way people in other countries do it?

Also, they have the really wrong headed appraoch to structural walls. They mistake "strucutural" for "foundation" walls, so all the walls work top down. I've been working hard with them to get them to change this. Do they really want to tell me that my 4 story 20" thick shear walls aren't structural walls?

I hope the Revit team is listening!!

Tom Weir
Los Angeles

[Batman]

What is the main difference between Revit Structural and Architectural columns?

[Steve_Stafford]

What is the main difference between Revit Structural and Architectural columns?Graphically speaking, architectural columns are absorbed into the wall(s) they come into contact with while structural columns are not. Try it, load both types and place each in a wall. This will demonstrate it "right quick"

[Batman]

Yep, I get it.

Thanks.

[gordolake]

Thanks Steve for that insight re columns / wall behaviour.

I'm progressing on a commercial project which will need bored piles at 3M c/c to a founding base between 3-5M below natural surface.
I wanted to create another surface to represent this, then place 450diam concrete piles in plan host them on the topo then attach each to under side of stepped strip footings.

Q1 Is there a way to have a topo based column family?
Q2 Could these columns be easily attached to the u/s of footings (modeled as floors) ?
or perhaps a separate site family to give the base level insertion point to then place the columns?

I want to be able to get concrete quantities and give pile depths to boring contractors.

Then above this i have masonry walls hollow core floor planks topping slab then steel columns to the roof frame.The roof is quite complex and all the columns will need to project to the roof rake line.

Q3 Is there a way top attach these columns to the roof?

Regards Steve.

[Chad Smith]

This one's been on my wishlist for a while now.

Sure that's how engineers design, but we are architectural designers, and I don't know one person who starts designing a building in Revit from top-down.
And even when engineers start modeling in Revit, I'm sure that they already have their design mostly worked out, whether it be on paper, structural analysis software or in their head, then they start the Revit modeling from the ground up.

It's the design that starts from top-down not the modeling.
Revit Team: Can we get this changed!!

[Steve_Stafford]

It isn't a top down design approach. It is a where you stand and where you look issue. Many of us draw plans describing the structure above us. Conversely, the structural designer does the same plan depicting the structure below us. True at least for most of the structural designers I've worked with. I'm not arguing that it should remain as is...just commenting on the perspective.

[beegee]

Ginger beers on this side of the pond do it that way to.

I can see why Revit set it up that way originally, but with the soon-to -be-released Structural package for Revit, it may now make sense to review and revise this aspect of Revit, so that the whole module acts as an architectural package.

( Ducking now to avoid the slings and arrows from outraged engineering types who are not going to buy the Structural package... )

[Nic M.]

Here too,

Maybe a preference to set
bottom to top
or
top to bottom

For the record i prefer bottom to top only for the Revit part of things

:beer: always top to bottom

[Chad Smith]

So did you vote (http://forums.augi.com/showthread.php?t=10844)? ;)

[aggockel50321]

Q1 Is there a way to have a topo based column family?
Q2 Could these columns be easily attached to the u/s of footings (modeled as floors) ?
or perhaps a separate site family to give the base level insertion point to then place the columns?

I want to be able to get concrete quantities and give pile depths to boring contractors.

Then above this i have masonry walls hollow core floor planks topping slab then steel columns to the roof frame.The roof is quite complex and all the columns will need to project to the roof rake line.

Q3 Is there a way top attach these columns to the roof?

Use the building pad tool to cut out your topo. For the piles, do one pad & then array it as required. You can then add another pad to cut out the topo for the footings.

You could then set the columns into the holes created. Columns run level to level, & can have the bases & tops offset from those levels.

You can then do a schedule that reports out the column volumes.

[Tom Weir]

What the heck are ginger beers?

[Steve_Stafford]

What the heck are ginger beers?Why...you Tom..."engineer"...

[Tom Weir]

Oh.....I get it.....
let me see then...architects must be?

[LRaiz]

I suspect that the real reason for structural columns go down as opposed to up from plan view level is mostly related to a miscommunication.

People make statements that engineers design from top to bottom and that kind of information probably led to the current UI without too much thinking. However what does the statement really means? I think it simply reflects the fact that while dealing with gravitational loads engineer first sizes the structure of top floors then takes resulting sizes into account while computing loads and subsequently sizing lower floor structures. On the other hand when engineer places a column I suspect he is still thinking of column going from the bottom floor to some higher floor, not the other way around. So, my linguistic guess is that miscommunication and different interpretations of the word design is to blame for the current user interface of structural column creation.

If my guess is wrong and structural people really would like to be looking at the top level plan while placing their columns then it would be nice to hear from them directly as opposed to hearing second hand statements and getting the real intent lost in translation. The absence of a strong voice from real structural people insisting on the current UI would suggest that placing bottom to top would make more sense.

[Steve_Stafford]

I suspect that the real reason for structural columns go down as opposed to up from plan view level is mostly related to a miscommunication.I think you are on to something here. Though not a real structural person I'd tend to agree that columns would want to be placed from a level up rather than down. What is visible in plan is where we are likely to want different results.

[Batman]

Its the general inconsistancies that start to develop out of software that remove its intuituve aspect.

Coluumns, architectural or otherwise, is about building modelling. One would assume that consistant approaches are maintained and when there not they seriously kill productivity.

I was certain that I was missing some setting and now I can't belive that it's actually been done that way.

Having now commited to Revit I am a little concerned about what other 'little' issues this software has. It seems as though there is still some level of refinement needed.

[Tom Weir]

I am not the engineer, but the draftsman in a structural engineering firm. I think you are correct about the miscommunication.

Usually in the schematic phase, as we begin, the engineer will forward the architect's schematic drawing to me. I start by linking in the floor plans from Autocad and go to the first floor plan. At this point we start developing our layout and decide on materials. Maybe I start with a W14x 61 column size and W24 girders, and W16 beams. I insert columns from the first floor to the roof, with a 12" or 18" offset below the first floor. I go floor by floor up to the roof.

The roof is always the worst one to do because of the sloping requirements. At this point we rarely get information on the roof slopes....too early in the design process. So we don't want to model too much there yet. And most architects do not show columns on the roof level.

To develop the physical model we have to work through the floor levels to see whether the columns interfere with the architectural layout.

Once I have completed the schematic physical model we export it out to the engineer to use as the basis for his analytical model.

I think our confusion might be between the physical and analytical models. And I was thinking how we often say to build the computer model of the building the way it is built in the field. I find that a very useful way to think about it. I notice you only mention engineers in your message. It's the draftsperson doing the heavy lifting when it comes to laying out the structure, not the engineer, at least at my office (we have about 30 structural engineers and 10 draftspersons. Smaller offices may differ on this but I still believe they would have to do a layout from the ground up.

The interesting evolution now with Revit is that the analytical model is right in there with the physical model. We are on the verge of attempting to do it this way. It has great potential.

And I will say again, it's the same for structural walls being done top down in Revit. I have had to change most of the walls I have made for 2 years on Revit because of it. Foundation walls can be top down, but not other structural walls (i.e. Shear walls, Tilt-Up Panels, Masonry Walls, etc.).

Thanks for your comments.

Tom Weir
Cad/Lan Manager
Brandow & Johnston Associates
Consulting Structural Engineers
Los Angeles, CA

[lev.lipkin]

Manual placement of structural columns and additional placement options in 7.0 (by picking grids: columns appear on grid intersections, and by picking architectural columns: columns appear on the placement line of architectural columns, see option bar when structural column tool is activated), make structural columns (and structural walls) to go down from level under assumption that the primary reason they are placed is to support what is on current level.

For same reason default structural template has different view ranges for level views (vs. default architectural templates) to be able to display not only what is on the level, but also to display structural elements which support what is on the level.

After placement, pick structural column or wall and set desired top and base offset (you would need to reset view range in default architectural template to see column or wall after placement). In 3d view top level is selectable in option bar. It maybe more convenient to place one column, change its properties as desired, then copy that column to other place on the level where it is needed.

When using 'Modelling' wall tool and if setting of 'structural usage' property is needed, pick on the wall after placement and modify its 'structural usage' property.

We understand that setting placement properties before actual placement for columns (similar for beams), as well as ability to do top-bottom attachments are desired, and will try to incorporate those in future development plans.

If current assumptions (outlined above) do not correspond to your needs and 'bottom-up' placement is desired, please let us know your needs with a few details on the goals of the task (for example, add structural elements to architectural model when positions of structural columns are well known).

[Tom Weir]

< make structural columns (and structural walls) to go down from level under assumption that the primary reason they are placed is to support what is on current level.>

as Leonid said this is the miscommunication between design assumptions and building a model during the duration of the design process.

<For same reason default structural template has different view ranges for level views (vs. default architectural templates) to be able to display not only what is on the level, but also to display structural elements which support what is on the level.>

this is true. Thus far the structural template has not been correct. We cut our plans about a foot above the level and look down.
i keep my view depth at about -4 feet below the level.

<It maybe more convenient to place one column, change its properties as desired, then copy that column to other place on the level where it is needed.>

what we would like is not to have to go that extra step and to be able to set the properties ahead of time as required.

<When using 'Modelling' wall tool and if setting of 'structural usage' property is needed, pick on the wall after placement and modify its 'structural usage' property.>

The confusion in terminology concerning the word "structural" usage needs to be addressed. "structural" does not mean down. As a structural guy I go to the structural menu to do structural walls. I don't want to go to the architectural menu and draw a wall and change it's usage to structural, then go back to the structural menu and wonder what the "structural wall" function is supposed to be. Or just change the word "structural walls" to "foundation walls" in the structural menu. Foundation walls working top down would be much more appropriate.
Most every wall I have done needs to be altered and I keep wondering why if you can do it on the architectural walls you can't do it on structural walls. There seems to be a conceptual misunderstanding.

<If current assumptions (outlined above) do not correspond to your needs and 'bottom-up' placement is desired, please let us know your needs with a few details on the goals of the task (for example, add structural elements to architectural model when positions of structural columns are well known).>

I am approaching this from a multi-disciplinary outlook, as a structural consultant who has his own part of the model. Never done it yet but hope to soon. I have gone over this with the structural product manager of Revit in detail. He should be aware of and part of this discussion.

I really appreciate your attention to this problem and have a great day.....

Tom Weir
Los Angeles

[lev.lipkin]

It will take some time (due to vacation and holidays) to check the sources of information to see if miscommunication (assumed by Leonid) really did happen.

I would ask Manager in charge of requirements to contact Tom Weir (and other interested parties posted in this thread). I expect that to happen in the beginning of January.

Default structural template has cut plane at 1', and bottom of the range at -4', about as Tom Weir described.

I appreciate your help.
Happy Holidays!

[ita]

I may be missing something here, but it seems that the confusion is not between the physical placement of a structural element (because the element is always where it is in physical reality to all observers) but rather how the various professional entities view its representational placement - that is perhaps creating the "confusion".

As Tom Weir relates in his thread, the structural engineers "install" their structural elements into the architectural fabric design (for their structural design analysis) - presumably top-down because that is reasonable and logical. In other words they work within an already designed spatial context - even if it is only notional line sketches/layouts on the back of the proverbial envelope.

It would seem (to me) that that the discussion point is around how the engineer or the architect or designer views and represents that element, rather than than how the element is placed within the envelope of the structure.

So, rather than having a different methodology to inserting the structural element as opposed to the architectural methodology, would it not be better to have a consistent approach to all elements (structural and architectural) and provide a choice in the manner in which the element is viewed? So the "View" dialog box could be switched between the representational views of the groups. (I imagine that the HVAC people would also like to have their representation view acknowledged).

In reality of the architect and the engineer are (all) viewing the very same element within its physical context; it is how they represent what they are viewing that differs.

So in maintaining the Revit philosophy of drawing it as it is built, then the structural elements need to be inserted into the model in a consistent manner with the other elements/objects inserted by the other professional groups. Perhaps this would remove the current confusion. And . . would reduce the confusion of us architects, designers. drafters in installing structural elements and we could then stop avoiding the use of structural elements in our documents!! - because they are too difficult to insert - at least from our representational view. :lol:

Providing a choice of "viewing" the representation - that is, a structural engineers view or an architect/designers view of the element, would restore consistency to the modeling methodology (and to how we use the model) while recognizing the difference in representation. :shock:

. . . . . wow that took some getting down :roll:

[gallienhanson]

It isn't a top down design approach. It is a where you stand and where you look issue. Many of us draw plans describing the structure above us. Conversely, the structural designer does the same plan depicting the structure below us. True at least for most of the structural designers I've worked with. I'm not arguing that it should remain as is...just commenting on the perspective.


Thats how we do it here...as you say the structure below us.

[cadkiller]

Group;

The issue should be where do you insert them when modeling your building. Not how they are initially designed or visualized.
They should be inserted at the level of origin and they should be started from the bottom and go up. When working on the foundation, they should be inserted at that level and go up 2 or 3 levels. Then you would jump up to the appropriate level where they are being spliced and insert the next set of columns at that level.

Isn't the first thing you do when designing a building is start with the foot print and work up. So why would anyone want to start with the top of a level and work down. I could understand for foundation walls; but not steel columns.

What they really should have is a 3D grid for inserting structural columns and beams. That way someone could pick a line and the object will be inserted to that line. I hope Revit structures has this and that this is fixed before it is released.

[Steve_Stafford]

Group;

The issue should be where do you insert them when modeling your building. Not how they are initially designed or visualized.This is what we are all saying...hopefully it's cleared up any misunderstanding that's been held.