Spanning constructs

[lukearh]

Hello,

I am having troubles understanding how spanning constructs work.

For example if I make the shell for a 6 levels building and the levels 1-5 are identical, I should make a constructs and check the levels 1-5 in the levels dialog for that construct. 

Now is what I dont know: The process of displaying that construct for all the selected levels shoud be automatic or I have to manually copy the construct from level 1-5?

I am asking because in my case is not done automatic, (I might be missing something) and if I copy manually is no difference if I check the levels or not in the levels dialog for the construct.

What is the correct way to do it?

Thank you.

[David_W_Koch]

You would only need a spanning Construct if one file was going to contain geometry that extends to multiple floors.  If you have identical geometry on several consecutive floors, and you only intend to model it once, then you could either create a single-floor Construct to model it once, and then copy that Construct to the other levels, or you could do the model in an Element file, and then set up Constructs for each identical floor and externally reference the Element file in each.  The latter would allow you to edit the geometry in one place and have the changes reflected everywhere, but would require that all floors where use are identical.

[lukearh]

Thank you for the answer.

The steps you suggested are the steps I also follow. But the question came when I studied an autocad architecture 2009 tutorial project - "Small Office Building_M".

The project has 2 shell CONSTRUCTS: 1 for ground floor and 1 for levels 01-04. The 01-04 shell CONSTRUCT is set to span for 01-04 levels, and opened it displays the shell for all spaned levels. 

If I remove the spanning settings for the floors 02-04 an leave it only for one level, nothing is changed. (or I didn't notice anything to be changed). The elevationsfor example lokks the same.

So again, the questions I have are:

1. How was the "01-04 Floor Shell" construct created? It seems it was created the 1st level then selected and copied for all the rest of the floors (in the same construct file, not using the "Copy The Construct to levels" command, which would resulted in creation of additional constructs).

2. If so, what is the point for checking multiple spanning levels in "Modify Construct" dialog? 

regards,

lucian

[David_W_Koch · Accepted solution]

If a single Construct file has geometry that covers multiple floors, then you would want to make that a spanning Construct.  Indicating multiple floors "tells" Project Navigator to make that Construct a choice when creating a View file that applies to any of the indicated floors.

If the file in question literally has a one-story-high set of exterior Walls and Windows/other openings, etc., that have been copied vertically for each floor covered by the spanning Construct, then there is no real difference between having all that geometry in one file vs having it in multiple files.  One possible advantage would be that if there were changes in the design (say a Window needed to move laterally, on all floors, you would be able to make that change for all of the Windows in one shot, rather than editing multiple files independently.  If all floors are truly identical, then you could have one file editing by using an Element for the geometry and inserting that Element into multiple Constructs, one per floor.  But if there were some minor differences between the floors, then using a spanning Construct would allow you to make changes to items that are the same on all floors (or multiple floors) with one edit, in one file.

I typically think of a spanning Construct as being used for geometry that spans multiple floors, such as a Curtain Wall might, or if you are using the stair tower generator.

[dbroad]

In addition to what David says, even a single stair (not just a stair tower) should be in a spanning construct so that it shows up in both floors that it connects.