Tutorial – AutoCAD Civil 3D Surface to Revit Topography

Over the next few months I will be posting some tutorials and workflows for taking civil engineering models such as drainage layouts and retaining walls from AutoCAD Civil 3D to Revit. The reasons for these workflows are to increase the Level of Detail and information that is held within the models. For example, the coordination and documentation of foundations with new drainage and existing underground services can be achieved very efficiently with the use of AutoCAD Civil 3D and Revit. This is even more relevant with the introduction of Autodesk Collections which will have Revit and AutoCAD Civil 3D available to all! See this link for a full list of products that are available in the Autodesk AEC Collection

https://www.autodesk.co.uk/collections/architecture-engineering-construction/included-software

In this first post I will concentrate on the fundamental task of getting a TIN (Triangular Irregular Networks) surface from AutoCAD Civil 3D to Revit as a 3D TOPO.

Triangulation

AutoCAD Civil 3D and Revit each use slightly different algorithms for the triangulation of surfaces. This could potentially allow errors to creep in if we simply rely on points and use these points to build surfaces in Revit and Civil 3D. In practice you should create the Revit Surface directly from the AutoCAD Civil 3D triangles. In the example below you can see a triangulation model from AutoCAD Civil 3D with the points shown in red and the levels shown in blue.

TIN Surface Original Trangles

In the image below the Revit Triangulation algorithm is shown in red. The points are connected in a different order and can cause minor differences in levels.

TIN Surface Revit Traingulation

To ensure that AutoCAD Civil 3D is showing triangles, select the Surface and then select ‘Edit Surface Style’ from the Right Click context menu. Select the Display tab, make sure that the View Direction is set to Model and ensure that Triangles are visible and all other component types are switched off.

Civil 3D Surface Style Triangles

Datums

To ensure correct coordination to Revit you should clearly mark a survey station that you would like to reference and also a project base point. An example may look similar to the image shown below.

Revit Project Base Point and Survey Point

Note that in the above example the Survey Point was unclipped and moved to the Station ‘ST1’. You could also leave the Survey Point at 0,0,0 which would be the OS False Origin. You should never unclip and move the Project Base Point as this can affect IFC datum and coordination with other models.

Coordinates can be given from either the Project base point or the Survey Point. You will also have to multiply the Easting and Northing by 1000 to take into account the scale difference between the Survey (in Meters) and the Revit Project (in Millimetres).

AutoCAD Civil 3D Export to AutoCAD

The TIN Surface in AutoCAD Civil 3D is a special object that cannot be used easily in Revit. The solution is to export the AutoCAD Civil 3D surface as an AutoCAD drawing. This will result in 3D Faces which can then be used to build the Revit Topography.

Click the Application Button, then Export and then Export Civil 3D Drawing.

Civil 3D Export to AutoCAD

The Export Dialog Box will automatically add a prefix to the drawing name to identify this as an AutoCAD drawing.

Civil 3D Export Dialog Box

One the export has completed the TIN surface will be represented as AutoCAD 3D faces. Make a note of the Layer that the 3D faces are positioned as this will be needed when creating the Revit Surface.

C3D to AutoCAD 3D Faces

Delete all other information and just retain the 3D faces and the datum’s as shown in the image below. The datum’s are very important for the coordination of the model within Revit. Scale the AutoCAD model from the Origin 0,0,0 and set the scale factor to 1000 (scale from Metres to millimetres).

Isolated AutoCAD drawing with 3D Faces and Datums

Revit Topography

Start a new project using your template in Revit. Make sure you switch to the site plan as the view range primary top and cut plane will be set to 10,000 to allow you to see the topograpgy.

In the Visibility Graphics/Overrides dialog box make sure that the Project Base Point and Survey Point are visible.

Revit Visibility Graphic Overrides Site Category

Next you link the AutoCAD drawing into Revit. Make sure that you set the import units to custom factor = 1 to ensure that there is no scale change. Also bring the AutoCAD file in Centre to Centre.

Revit Link CAD File Settings

Once the AutoCAD file has been linked it is a good idea to set the Visual Style to Wireframe to allow you to see the Setting Out information through the 3D faces.

Revit Set Visula Style to Wireframe

Unclip the Survey Point and move to the Survey Station of your choice (In this case STN1). Note that you will need to unclip the Survey Point, move to the location and then clip the Survey Point. I would then suggest pinning the AutoCAD drawing along with the Project and Survey Points.

Revit Project Base Point and Survey Point

Your Model is now coordinated!

To create the Topography, make sure that you first set the category to visible. Click the Massing and Site tab and select the Toposurface Tool.

Revit Toposurface

Click the ‘Select Import Instance’ from the context menu and select the linked CAD file.

Revit Select Import Instance

Do make sure that you now select the Layer where the 3D faces (triangulation) are positioned. You will now have a Revit Toposurface with Identical triangulation to your AutoCAD Civil 3D model.

Revit Toposurface From Civil 3D

Hope this helps,

LawrenceH

Revit 2018 – New Reinforced Concrete features

In each release of Revit we are now seeing a continuous trickle of new features and improvements to the Reinforced Concrete modelling and detailing capabilities. Most of the ‘standard’ features are already firmly established and now Autodesk move on to the reinforcement of complex concrete forms and cross platform workflows. As discussed in my previous post on the Revit 2018 steel detailing features, Autodesk have some stiff competition in this area and are quickly closing the gaps. Also an expected delivery of a BIM project is a complete 3D model and it may no longer be appropriate to issue flat 2D drawings and a bending schedules. Some of the new tools will be very useful in Civil projects such as Tunnels, Bridges and roadside structures where the geometry is likely to be curved and sloped.

I have tested all the new features and will start with the main function of the reinforcement of complex concrete features. In the image below I was able to add 4 L bars in plan and then create a varying range to the inverted truncated pyramid shape.

Revit 2018 New Rebar Features

I also tested the varying distribution on other native Revit in-place families and did struggle with twisted and double curved objects but in general, this new function is very useful and saves a lot of time. In fairness I would image that you would need extra control over double curves and twists and likely have to use something like Dynamo to place ‘real’ reinforcement in a logical way.

Revit 2018 Curved and Multi Planar Rebar

Another refurbished tool is the Rebar graphical constraints. This tool enables reinforcement bar to be constrained in 3D views as well as the traditional 2D views. The user can selected the rebar plane or the end points of the bar and then constrain this to a relevant plane on the host element. In the image shown below you can see the bar plane constraint being set and then the end of the L bar to the front face.

Revit 2018 Graphical 3D Rebar Constraints a

The reinforcement bar also has Bar Handles that allows the physical leg lengths to be dynamically edited which is quite handy when you need to drag the bar around in the 3D view. The graphical constraints will still show the check box to snap the bar to cover.

You can now directly import a 3D solid from another CAD application (AutoCAD, Rhino, Trimble SketchUP & Bentley Microstation) and host reinforcement directly into the elements. This is a neat workflow when coupled to tools such as Infraworks. You can create a bridge and then export this directly to Revit and then add reinforcement.

3D Ramp from AutoCAD to Revit Rebar

In the example above a 3D ramp has been modelled in AutoCAD and then directly imported and reinforced within Revit. In practice this is only useful for single elements and not an entire bridge as you will need to import each solid separately and then set the correct Sub Categories and parameters.

In conclusion Autodesk continue to strengthen the Revit application and make the legacy 2D detailing a think of the past.

lawrenceH

Revit Structure 2014 Tutorial – Modelling piled wall systems

Link to YouTube Video:  http://youtu.be/XXRjqQJn3BY

I thought it was about time to produce a post and tutorial on piled wall such as sheet piling, contiguous and secant piled systems. On a recent customer project we had to model some sheet piling and in previous projects I had used curtain systems to produce the layout with mixed results. I have found that the best current system for the modelling of sheet piling is to use adaptive components and then apply this to a divided path.

Revit Piled Wall

The first stage is to model your pile family. The Pile family is modelled within a column family template. I downloaded a profile of a sheet pile and then used this to create a simple extrusion with a parameter to control the pile depth. Make sure that you set the pile to always be vertical within the Family Categories & Parameters otherwise you may find that you have horizontal piling!

You then create a Metric Generic Model Adaptive.rfa family and insert the pile family into this. Place a normal Revit point and make this adaptive as shown below.

Revit Adaptive Component

Start a new Metric Generic Model Adaptive.rft family and then draw your intended path for the pile component. It’s worth remembering that you can of course import a CAD file or an image into his family to help with the layout.

Metric Generic Model Adaptive CAD import

Start a new Metric Generic Model Adaptive.rft family and then draw your intended path for the pile component. It’s worth remembering that you can of course import a CAD file or an image into his family to help with the layout.

Divide Path Icon

You can then configure the divided path within the Properties Palette. Note that I have set the layout to Fixed Distance and the Measurement Type to Chord Length. In this example the width of the sheet pile is 900.

Revit Divided Path

Next you load in your adaptive pile family. On the Create Ribbon use the component tool and insert your pile at the end of your path making sure that you snap it on one of the points. Select the pile and then choose the Repeat command as shown below.

Revit Pattern along a path

You will now see your piling layout. You can now load this back into your project. The piles can be scheduled if you have set the family to use the Shared property.

Pile Layout

Here is another example where the path is travelling through 3D space. Very useful for infrastructure projects. Form more information see my YouTube Video:http://youtu.be/XXRjqQJn3BY

Revit 2014 Sheet Piling

 

Hope this helps,

LawrenceH

Revit Structure – Beyond Buildings web seminar

Just thought I would point you to a free web seminar that we are running on the 31st July where we will be investigating the usage and collaboration between Revit Structure 2014 and Civil 3D 2014. In this particular seminar we will focus on taking data from Civil 3D to Revit Structure for the creation of a half through rail overbridge.

Revit image 1

AGENDA

  • Realistic workflows between Autodesk  Civil and Structural Software
  • Workflow Example: A Rail Overbridge
    • AutoCAD Civil 3D Alignment
    • Extract the corridor
    •  Import in Revit structure
    •  Design of super and sub structures
  • Workflow benefits in the real world
  • Choosing the correct Autodesk Suite for your discipline based on your project deliverables
  • Conclusion
  • Q & A

If this is of interest please register at the following webpage.

http://www.excitech.co.uk/news/events/revit-structure-beyond-buildings.asp?cc=rsbbsm

lawrenceH