Finding center of gravity

[haydenwse]

In AutoCAD when I needed to find the center of gravity for a shape I would create a region of the shape and use the mass properties to find the C.G.  is there any way to find the center of gravity for a shape in Revit?

[Anonymous]

I belive there is no direct solution for calculating center of gravity in Revit, Though I always export my element as geometry or AutoCAD Architectural objects from Revit and then find the C.G. in AutoCAD Architecture. 

[haydenwse]

That is what I thought.  I find it completely ridiculous that this program cannot give C.G.  I work with precast concrete and have to find the CG to determine how to pick up the pieces.  I don't believe that it is not possible for Revit to output this info.  The programmers just don't think that it is important. 

I for one could really use this feature.

[Anonymous]

Autodesk....Any Answers?

[haydenwse]

Does anyone have any ideas for this issue?

[Anonymous]

Guess there might be a market for an Revit add-in for the precast detailers. 

Post the question to the http://thebuildingcoder.typepad.com/blog/ and in the Revit programming forums.

Who knows, you might get lucky.

M.

[Anonymous]

i would be interested in knowing if you ever came up with a solution.  I would like to find the CG for something with two materials such as a precast stair tower box with a flight of steel stairs on one side.  sure revit structure does know where the center of gravity is.

[haydenwse]

Never did find a Revit solution.  I have been exporting the product to dwg file and use autocrat to find E.G..  It is about all that I use autocad for any more. 

I still can't believed that autocad can do this and Revit can't.

[Anonymous]

we need more precasters speaking out.

[Anonymous]

This is not just a construction industry issue. Oil and Gas need C of G for steel work and platform lifting. If we cannot calculate the c of g we cannot detrmine the correct lifting points and additional steels required for placement.

AUTODESK, Please consider adding this functionality in as it is a real benefit to many users.

[LyleHardin]

I'll revive this old thread. We too, would like to find the C.G. of a truss we are lifting. Actually, it's a huge piece of ductwork for a power plant, but basically, it's a truss made up of W shapes, tube steel, and 1/4" plating for the outer skin. We're determining the lifting points. We get the Revit file from the manufacuterer and we can export to AutoCAD as 3D solids, but I have to extend the steel beams to the columns first, so it's not quite perfect. So, yeah, it would be nice if Revit could pop in a symbol or sphere or something at the C.G. 

[haydenwse]

I think that it is ridiculous that Revit DOESN'T calculate CG.  it has all of the geometry, volume and material density info build into it.  from there it can't be much of a programing challenge to output CG. 

It is just a matter of the programmer's thinking that because THEY do not need CG then nobody does. 

[L.Maas]

I can imagine that COG is not a default feature. Lots of thing in Revit are only representations of the objects. So COG of a Revit family can be totaly inaccurate.

However with the use of Dynamo, things can be done

[haydenwse]

Ok, i'll bit.  What is dynamo?

I do not buy that Revit could not calc an acurate CG as long as it was correctly modeled. 

Revit is a tool and as always it is the engineers responcibility to correctly use the tool and asses the resolts to just saying that it might be missused they you might as well close down AutoDesk becasue the same argument could be said about every feature of every software.

[L.Maas]

You do not have to bite. 😉

Revit can calculate the COG, basically shown in previous screenshot.

Dynamo used to be and add-in for Revit, but since Revit 2017 an integral part of Revit.

It is a visual programming environment to make use of the Revit API. The screenshot in my previous post is the 'code' to determine COG of a selected object. In this case it places a family (in this case the red ball) at the COG of the selected object.

[haydenwse]

I haven't yet moved into R2017 because I need to stay with the version that the rest of the design team is using.  At this time i am useing 14, 15 and just in the last couple of months 16.  It will probably be a year before i can move into 17.  How do I get it for those versions and is there a tutorial on how to use it?

[L.Maas]

In my previous post was a link to the Dynamo website (http://dynamobim.org/). There you can download it. The installer will indicate for which Revit versions it can be installed. There is a forum, there are learning files etc.

[haydenwse]

This looks interesting.  i downloaded Dynamo and was able to add all of the nodes that you show on your example but have no idea what to do with it.  can you pont me to a tutorial on where to go from there?

[L.Maas]

When you start dynamo from Revit, it connect automatically to the active project.

You have to run the code. This can be done by selecting "Run Automatically" and then click on the "Run" button.

The object in the Family Types node is the object/family that will be placed at the COG

This code expects that you select an object (Model Element). In your case press on the Select button (Select Model Element node)

Because my code was already running it shows for me "Change" (might also differ between different versions of Dynamo)

After pressing "Select" navigate to your Revit project and select the object you wish to determine the COG.

If everyhting is correct a family instance of the family mentioned in the "Family Types" node will be placed at the COG of the selected object.

If you want to explore this further take time to go through the documents/tutorials on the Dynamo website.

A good starrting point is the Primer on the Dynamo website HERE.

It is a real powerful tool.

[bradwitt]

 How can I utilize this script to find my COG of a generic model? I work for a company that does formwork for concrete and the vast majority of our formwork are generic models. Any assistance would be greatly appreciated.