Cutting linked CAD solids with a void

[eugene.stolberg]

Hi all,

I am trying to see if its possible to cut a linked CAD file with a void, kind of like doing an actual subtract on the model. 

The context is that this project we are working on requires delivery in Revit (the project managers agreed to delivering an infrastructure project in revit, but thats another story), and we have alignments that drive our design and corridor models, which are then exported into CAD for revit links.

So in summary, our workflow is basically as follows:

-Create Corridors that are necessary

-Export Corridors to Solids into a ACAD file

-Link Solids into Revit model

Now this works for the most part, when the corridor model can build everything we need. However we have our piers and vertical elements in revit. A situation has now been realized that a corridor needs to be 'stepped' according to the geometry of the abutment for example. Now if everything was in CAD or all in Revit, easily done. Subtractions in CAD, and voids in Revit. But being that we are in both and trying to make it somehow compatible, we have to effectively use the geometry in a revit file to clip a corridor. 

The only method I have tried is to make a void inside the generic model family we have that import being brought in, but this doesn't do anything and the void just ignores it. 

Is this something that is just too far out of the capabilities of Revit? This is probably an extreme case and we are trying to push the envelope with our usage, but if a solution exists it would be helpful for the next steps as this will start returning soon. 

Screenshot example attached.

Thanks,

Eugene

[ToanDN · Accepted solution]

You cannot change the geometry (yes cutting with a void counted as one) of a link in Revit. You can't even do that if the link is a native Revit model.

Your best bet would be import the solid into Revit to create a mass form. Then, you will be able cut it with a void.

If you can go with this workflow, you can eliminate the involvement of AutoCAD altogether.

[eugene.stolberg]

I thought that would be the case. Sadly we may not be able to do an import as a mass since the workflow change would be to make the corridor, export to solids, import into revit, then cut the object. The import to revit is the piece of workflow we are trying to minimize having to do so that we dont need to do a new import each time theres an update.

I guess we will have to figure out a way to do it in cad before the import then.

[ToanDN]

Just curious, which program do you create the solid from? My understanding from your description of the workflow is that it is not AutoCAD.

If the corridor design keep changing, you could export the Revit void (or the geometry resembles the void), to a solid. Import it into the native program and locate to the correct coordinate. Then, use the geometry to cut the corridor.

[eugene.stolberg]

We use Civil3D, and since Revit cant directly read C3D corridors, we use the tool to extract corridor to solids which then Revit can read just fine.

The alternative method is most likely what we are going to end up going with actually. Might be simple to just incorporate the void solid into the abutment family and export it to get the void geometry, but I am still trying to coordinate with the others on which might be best for us and the rest of the teams.

[ToanDN]

I am not familiar with Civil3D but if you can import a 3D DWG or SAT file exported from Revit into it then you don't need to use AutoCAD as an intermediary.

[eugene.stolberg]

Civil 3D is the same thing as AutoCAD basically. The only controllable export we have to get the model elements into Revit has them as AutoCAD 3D solids. I have been...sternly warned about using excessive export/import formats, so we are trying to stick to CAD/Revit where possible.