Archive for October 2009

Revit Model Review

Autodesk have just released a new module for the Revit Platform called Model Review. This is part of the Subscription Advantage Packs that have been released for a multitude of Autodesk products.  Unfortunately, at the present time, most of the Revit packs are not working due to installation problems. I will notify you when this is resolved!

The Revit Model Review tool is essentially a BIM checking utility which allows you to check certain parameters and families within your model for particular value ranges. When we think of a CAD Standard we generally expect to see references to line weights, line types, text styles etc within the standard. This is all well and good for typical 2D drawings but what about BIM models? The BIM model will contain a multitude of information that we will likely use for the design, construction and management. It is therefore vital that this data is present and correct but how can you check that the extended data exists? How can you check that door heights and widths meet your design standards or that rooms volumes have been correctly defined before running airflow calculations?

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Using the Revit Model Review.

The tools provided are simple to use and understand but provide powerful checking and verification functionality. The first step is to set up the standard and the various criteria to check. This is done within the Manage command. You add various checks to a standard. Below I have added a check for Views with Hidden Elements. Other checks may include minimum and maximum sizes for Revit elements or that Spaces and Room areas are correctly defined.

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You then continue to add your required checks and configure the check properties, filters and Pass and Fail Messages that you want Revit to provide.

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To assist CAD/BIM managers, there is an option to check multiple Revit projects and also linked files.

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Here you can see the results of the check. A report has been presented showing the Views that have hidden elements and the quantity of hidden objects. A nice feature of the checker is that you can repair the issues automatically by clicking the Fix icon shown in the dialog box below.

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In summery I think this will be an area that Autodesk will need to expand into and this is certainly a good start. With so much design and construction information now stored within the Revit model and the fact that many customers are directly linking the Revit models to design tools such as ROBOT this is a vital area that needs addressing.

Food for thought,

I would be interested to hear any comments that you have around this subject.

Lawrence

Civil 3D surfaces into Revit

For those of you who have both Civil 3D and Revit in your toolkit, here are a few options to help you get your surface from Civil 3D into Revit.

Surface viewed in Civil 3D

Surface viewed in Civil 3D.

Revit has tools to create it’s own surfaces – called Toposurfaces – from either drawing data or from a point file (text file of XYZ co-ordinates). In this post we are going to take a look at creating a Toposurface directly from the Civil 3D surface object. The first thing to understand about the way Revit creates it’s surfaces is that just like Civil 3D they are formed from a series of triangles. Unfortunately, unlike Civil 3D, there is no way of automatically controlling how the triangles are created (no adding of breaklines, no option to swap triangle edges, etc). So, how faithfully Revit reproduces your surface may depend a lot on how you take it across – and there is no single method that works great for all circumstances.

Setting up the Civil 3D drawing

Create a new drawing with ONLY your Civil 3D surface in it. If you import a Civil 3D drawing into Revit, and you have both Civil 3D objects and the polylines, text, points and other AutoCAD information you used to create your surface, Revit can get confused with the co-ordinates. I have found the best way round this is to use Data shortcuts in Civil 3D to recreate the surface in an empty drawing, with a co-ordinate reference point (such as a Survey station or other known point). Civil 3D point objects don’t show up in Revit, so if you use a Civil 3D point as your reference marker, explode it before saving the file.

Importing into Revit

 

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Using the Import CAD tool in Revit, you can import your Civil 3D drawing.

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The best results are obtained when setting the import units to metres  rather than “Auto detect” (make sure Civil 3D has the AutoCAD units set to Metres!) and positioning Manual - Centre . This positioning is important – you may be tempted to put it at the correct co-ordinates (Origin to Origin), but as you will probably have some large co-ordinate values, you certainly won’t want to use these in Revit.

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Use the Revit Survey Point and Project Base Point to align the surface drawing to your project. Use the “move” tool in Revit to move the entire import instance based on the reference point you added to the Civil 3D drawing, snapping onto the Revit Survey Point.

Surface From Contours

One option is to set the display of the surface in Civil 3D to show contours. This is achieved by using or creating a suitable contour surface style with the intervals set appropriately. If you use this option, then you need the contours spaced close enough to model the details of the surface, but not too close that you end up with a huge surface in Revit.

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Use the Toposurface tool , “Create from Import”, “Select Import Instance” in Revit to create the surface by picking the import instance.

Switch to a 3D view in Revit, and then change the visibility / graphics settings so that the Toposurface is visible.

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When you finish the surface creation, you will see the contours from the imported drawing, together with the shaded Revit toposurface. Notice where the Civil 3D contours disappear below the Revit surface, showing the differences in the way the two surfaces have been triangulated.

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Surface From Triangles

You can also try using a triangle display from Civil 3D. Since Revit does not honour every triangle formed in Civil 3D, there will be some discrepancies in the results. Set the surface style in the Civil 3D drawing to one that shows triangles in both plan and model views.

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The image above shows the Revit triangle sides highlighted which don’t conform to the Civil 3D triangulation. However, if your Civil 3D surface has triangles which are evenly spaced the you should get a reasonable result.