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3D Faces ri a single enclosing 3D Polyline

Steve Wheatley

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I have a series of 3DFaces provided by the project civil engineer - these elements represent footpaths, roads, cycleways etc. These elements are sloping on various grades as one would expect. I'd like to generate a 3D Polyline that forms a boundary around all the elements that form a section of road or footpath. I can use the 3DPoly tool to visit each external vertex and snap to the vertex but is there a tool or Lisp program that can do this automatically? I've tried the LineworkShrinkWrap command but that doesn't retain all the correct Z values for the external vertices.

In the attachment, the layer DESIRED RESULT (magenta) is what I am trying to achieve.


Many thanks in advance!



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I've updated the CAD example to fully illustrate the problem


original 3d faces (CYCLEWAY layer - brown)

lineworkshrinkwrap (LINEWORKSHRINKWRAP layer - yellow)

desired result (DESIRED RESULT layer - magenta)



The desired result was manually created by tracing the extent of the 3DFaces using 3DPOLY command.


Hopefully this makes more sense?



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Bigal, thanks for your reply. I have to disagree. LINEWORKSHRINKWRAP in Civil3D doesn't do what I want. The magenta and yellow lines are different. The magenta line is what I want. I've attached some screenshots - you can see the difference between the original 3D faces, the 3D polyline (magenta) manually traced using 3DPoly and the result from running LINEWORKSHRINKWRAP in yellow.


BTW - my profile is correct - I am using Revit mostly, and this particular workflow is to allow me to create Revit Floors automatically from Civil3D elements using Dynamo.


Original 3Dfaces = brown

Manual trace with 3DPOlY = magenta

Shrinkwrap = yellow

Difference shown in the last image


Difference between manual trace and shrinkwrap.jpg

Original 3D Faces.JPG

Manual trace using 3DPOLY.jpg


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Revit has nothing to offer? So you're looking for a workaround for a workaround based on conversion using (the famous) Dynamo..?


I think you just should not use Revit and DWG for Civil use in the first place. You're asking for trouble, world of pain, still leads to DWG in the end.


My cent!

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Thanks for your reply Halam. I'll take it on board.


Thanks for taking that as my bold reply ;-)


I'm not sure you want to stick to Autodesk 'infra sollutions potfolio' either as a matter of fact

Why not try to find a more exotic and suitable elsewhere, i noticed some great things hapenning at Sketchup. Which most of the times is fairly good dwg compatible. Way better than the Revit beast. I'm not familiar with .skp abilities within the Dynamo playfield. Centainly there can be found some workflow skp into Revit.


Check this


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SLW210 - I stand corrected. CadTools DOES have what I needed! Convert 3DFaces to 3DPolylines. It seems to do exactlty what I want. Glad I went back and had a closer look. Many thanks for your time and suggestion.


In case any other newbie needs to know CadTools can be downloaded from here: http://www.glamsen.se/CadTools.htm

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Hi Halam

The project I am working on requires we use Revit and unfortunately our practice isn't in a position to dictate otherwise. Personally, Revit is a pain in the backside (for Landscape Architects) as it isn't really designed for hard landscape works. I'm not a civil engineer so I do not use Civil3D on a regular basis although our practice has licence. I have had to write code to convert 3D CAD linework into Revit Floor elements. This was the last piece of the puzzle. Turns out that CadTools has the tool to do the trick.

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Thanks SLW210 - turns out you were right and CadTools does have the tool 3DFaces to 3DPolylines. Glad I wennt back and checked again!

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I thought it might have, I haven't needed CADTools for a few months so couldn't remember, but was pretty sure I did something similar a while back.


Glad it worked.

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