Trying to use an AutoCAD surface as a cutting object in Revit

[Sahay_R]

Situation here - I have a surface that was created in AutoCAD. I would like to bring it into Revit and use it as a cutting object to cut a solid. 

My thought was to bring in the surface as a roof, and model  the volume with Walls. 

Steps I have taken so far - 

Exported the surface to DWG - imported to RVT - when imported DWG is exploded to isolate the surface, then it disappears. No go.

Opened the DWG in 3DS Max, selected and exported the surface to a SAT. Am able to import it to RFA, looks fine in 3D, but disappears in orthographic (plan, section, elevation) views. The same behavior occurs in RVT files.

The other route of course would be to carry out this operation in AutoCAD with the SLICE command.

DWG file attached. For some reason can't attach the SAT. Revit and AutoCAD 2022

Any thoughts, please?

[ToanDN]

- Import it in an in place Mass or a Mass family

- Create roof by face from the Mass

- Attach walls to the roof

[Sahay_R]

Thank you, @ToanDN . Here's the rub - when I insert the SAT into an in-place mass in the project, it disappears. Even in 3D.

[Sahay_R]

....even in a Mass Family

[Sahay_R]

I can only see it in a Generic Model family. When added, the surface disappears.

[ToanDN]

It shows up fine here.  Make sure Import category and Mass category are visible.  Import in a uncropped plan view (not a view placed on sheet), location center to center and move just in case it is far from your model.

And to attached SAT, you need to zip it.

[Sahay_R]

Aaaahhh - NOW I got it - the SAT step was totally redundant. Just DWG >> Mass >> Roof by Face. Awesome!!

[ToanDN]

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@Sahay_R wrote:

Aaaahhh - NOW I got it - the SAT step was totally redundant. Just DWG >> Mass >> Roof by Face. Awesome!!

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The reason your SAT is empty because they are surfaces, not solid.  Only solids can be exported to SAT.  What is it anyways?  By the shape of it,  I think you will have hard time creating roof by faces.

[Sahay_R]

Yep. Roof by faces is turning into a regular pain, especially with the really tiny slivers of roof.

These are lines of sight. They need to cut through the terrain. 

Actually, the SAT shows up fine in 3D in a Generic Model family.

Any other thoughts?

[Sahay_R]

Which is why I wanted to bring in the surface to use as a cutting piece in RVT.

[ToanDN]

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@Sahay_R wrote:

Yep. Roof by faces is turning into a regular pain, especially with the really tiny slivers of roof.

These are lines of sight. They need to cut through the terrain. 

Actually, the SAT shows up fine in 3D in a Generic Model family.

Any other thoughts?

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Terrain?  You mean the topography?  Don't bother convert it to Revit roof then because only nothing can cut a topo except building pads.  Keep it as import in a Mass or Generic model and visual to find out area clashes to lower the topo (graded region or whatever method you find suitable).

[Sahay_R]

Team member has a block of geometry - and wants the to surface of the block to follow this surface - which means that the surface should cut the block to reveal an undulating top. 

[ToanDN]

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@Sahay_R wrote:

Team member has a block of geometry - and wants the to surface of the block to follow this surface - which means that the surface should cut the block to reveal an undulating top. 

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If you override the block under the surface to a bold color solid pattern, set the view to hidden line then the parts of the block stinking up above the surface will show visually.  

[Sahay_R]

@ToanDN - not working. Even simplifying the lofted surface keeps giving the error that Revit cannot make roof. 

I've attached the surface - this is simplified from what it originally was.

[ToanDN]

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@Sahay_R wrote:

@ToanDN - not working. Even simplifying the lofted surface keeps giving the error that Revit cannot make roof. 

I've attached the surface - this is simplified from what it originally was.

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You are not going to be able generate Revit roof from those slivers. 

Either model the entire line of sight as a NURBS in Rhino and export it as a ACIS solid SAT file, import it as a solid Mass or generic model, the you might be able to cut/join geometry it with Revit's elements.

Or do what I suggested earlier "If you override the block under the surface to a bold color solid pattern, set the view to hidden line then the parts of the block stinking up above the surface will show visually. "