Wednesday, June 30, 2010

Clipping of DWG links

I’ve never been a fan of DWGs in Revit projects and my attitude persists. When I started using Revit in 2006, I came across several pitfalls that still lurk with us today in 2010. I think one of them is worth mentioning.

As you might know, when x-ref’ing a dwg into another dwg, you need to decide whether it will act as an Overlay or an Attachment. As a rule of thumb, I always suggest to use the Overlay option. The Attachment option is only to be used when you want that x-ref to come in when the parent dwg is inserted/linked. This is identical behavior to linked Revit projects. Any linked dwgs in Revit will bring in other x-refs if they are Attached and will ignore them if they are Overlays. So far so good.

The one major shortfall is that Revit ignores the clip boundary. It is very common when x-ref’ing a dwg to customize the clipping boundary. You obviously have good reasons to do this, but Revit completely ignores it. For example if I have a dwg file with several clipped x-refs and decide to link it into a Revit project to make it part of the rest of the drawing set, you get undesirable results, and end up with an overlapping nightmare of lines and text. There is really no solution to this issue, unless you are willing to live with some really ugly workarounds, which I’ll refrain from posting!

I wonder how many more years we have to wait to get this functionality? I know I know, just don’t use dwgs. That is usually my answer too!



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