CAD for Ventilation

Good afternoon

I am currently working at a sheet metal fabrication company and we manufacture our own rectangular ductwork and exhaust hoods.

I have been looking at ways of speeding up the time we need to turn around drawings for ventilation systems. Quite often our drawings have to be submitted to local councils for planning so we need to create several elevations which in 2D autocad can be quite time consuming.

I have been experimenting with Autocad MEP and Revit MEP but I cannot say I am very pleased as they both seem to do some of the things I need but not all. I have been using Autocad and Inventor for years but never worked with any MEP package.

My main problem is when we are trying to create an elevation drawing (front view for example) from a 3D model in Autocad MEP I cannot add dimensions like duct length. I can only do this on plan view. I can add size labels etc but I cannot give an indication of how long a duct segment is or how long a square to round transition is.

On Revit MEP on the other hand I can add dimensions on all views but the ductwork is shown like a straight continuous piece, instead of having connection flanges every 1250mm or 1500mm.

I have tried to find solutions over the internet, even purchased books for both Autocad MEP and Revit MEP but could not find anything. Am I missing something?

Since you're a fabricator, look into this instead:

http://www.autodesk.com/products/fabrication-products/features/fabrication-camduct/all/gallery-view

For fabrication, I think you would be happier with software that is designed with that in mind. AutoCAD and Revit MEP are more for the design side. I'm not familiar with the fabrication side, so I'm going to leave the recommendations to someone with first hand knowledge.

Now that I am reading my first post again I realise I might have given the wrong information.

We do not need Revit MEP or Autocad MEP for the fabrication part of the business. Our fabricators are old-school and they work out their cutting lists from the main drawing, I know it is so 70s or 80s but it works for us, at least for now. So in this sense CADmep will be redundant as no one will use it even though it is the right way to go (maybe in the future).

We need to create isometric, plan, side and front views faster but when I create the model in Autocad MEP I can only add linear dimensions to the plan view and I cannot add linear dimensions for example on a side view showing a 6 meter riser, so we do not have a reference of how long each individual piece of duct is, especially transition fittings like square to rounds. On Revit MEP on the other hand I can do this but it will show the whole length of the duct run as one piece. If I submit this drawing to planning authority they will return it and ask me to show connection flanges.

So are there features I am missing in Autocad MEP or Revit MEP that will solve my "problem"? One of the main reasons we want to stick with Autodesk is that we already have models of our exhaust hoods in Inventor so we can easily export them to Revit or as MvParts plus all the staff in the company is familiar with Autodesk products.

At the moment we have trial versions of both Revit and Autocad MEP and we are trying to make a decision on which way to go.

I see. Now that you've given additional info, 2 things you can do:

• AutoCAD MEP, become familiar with altering the UCS so you can dimension things accordingly.
  
• Revit MEP, use the Split Element tool to create "flanges" with a custom Union Family.
  

Revit will be much easier in producing BOM data in a schedule form, but you'll be responsible for setting it up AND you'll have to create some custom fittings along the way. AutoCAD MEP has much more fittings out-of-the-box and has extra tools that aid in a more real-world feel (e.g. separating duct joints by lengths) but creating custom content can be far more complicated and the scheduling abilities to produce a BOM data sheet is far less than satisfactory.

There are pluses and minuses in both. Revit will give you far greater versatility and longevity but will require more setup on your end where as AutoCAD MEP will give you the quicker fix for the time being but you will hit major walls in the long run.

Of the two, I would suggest going with Revit. I've heard of at least a couple of ways to show flanges but am not versed on them.

Manos84, check this link out: https://dl.dropboxusercontent.com/u/4989089/S09_S14_Handout_MEPFabricationModelinginRevit_M_Nelson.pdf

And the supporting Powerpoint Slides: https://dl.dropboxusercontent.com/u/4989089/S14_Pres_MEPFabricationModelinginRevit_M_Nelson.pdf

The presentation is about piping but this can be equally applied to ductwork for Revit. This should give you a great intro into setting things up for fab level shop drawings.