So Many .DWG backgrounds, So Little Processing Power…

So Many .DWG backgrounds, So Little Processing Power…

Last week, I wrote a post about some general concepts regarding collaboration and data exchange. The hard truth is that while we are all pushing for 3D collaboration, we’ve all got consultants that will be stuck in 2D for years. It might not be your structural engineer, but there’s going to be someone sending you flat information. While you need to keep pressing ahead with more complexity and detail in your BIM, you also need to know how to smartly integrate materials from less evolved collaborators. As a leader of the BIM revolution, you should aim to always be in a more advanced position than those around you.

People sending you .dwg backgrounds?

I typically deal with one of three scenarios.

Consultants. Fortunately these are becoming less frequent. I’ve been doing residential for the last five years, so I honestly don’t see many consultant drawings. And those that I do get aren’t always digital. So let’s gloss over these for now.

Slices of a SketchUp model. I had one coworker who would do incredibly detailed SketchUp models. When it was time for me to get involved in a project, I’d save out .dwgs of the elevations, plans, and sections and then build everything from scratch in ArchiCAD using the .dwgs as underlays. I would also use the SketchUp model as a reference for measurements that there were missed in the 2D exports. I got pretty fast at it. Fast enough that I started modeling things in ArchiCAD for export to SketchUp for those people who only knew SketchUp. I can talk endless about this situation, but I’ll stop here. Let me know in the comments if you want more and I’ll be happy to elaborate.

AutoCAD drawings of existing conditions. There are a lot of great ways to get as-builts directly into a 3D format. Old fashioned measuring and then modeling directly into ArchiCAD is what I’ve been doing for years and years. Orthograph and other tablet programs bring documentation onsite into the 21st Century by making pencil and graph paper obsolete. When I get an iPad or tablet, I’ll definitely write about my experiences with these apps either here or over at Shoegnome.com. But once again, I digress. More often than not, when working with as-builts I’m dealing with old 2D drawings of existing conditions. Maybe a building owner has them on file, hired some cut-rate drafter to measure and document the site (I hate working off as-builts someone I don’t know or trust did), or perhaps they were done by someone else in your firm a long time ago. Whatever the reason, we’ve all dealt with this. And will continue to for longer than we should.

If you have to Import DWGs, at least be smart about it.

You’ve got 2D content from somewhere. Now what?

  1. Create an independent worksheet, call it ‘underlays’, and save the view. For speed, include this independent worksheet and saved view as part of your template.
  2. Place all the .dwgs, pdfs, etc. on this worksheet. Just drag and drop the external content from wherever it lives on your computer to the ‘underlays’ worksheet. The external content will be placed using the Drawing Tool. This is great, way better than placing .dwgs as an xref (or heaven forbid merging the .dwg with your .pln) because reference layers won’t clutter your file. All the layer information for each .dwg will be separately accessible via the placed drawing’s settings (embedded layers are a godsend). Also pens can be set to match the source file, black and white, grayscale, or any of your pensets.
  3. When placing multiple drawings, insert them a known distance apart and align elevations, sections, plans, etc. If you have 5 floor plans place each 50′, 100′, etc. apart vertically or horizontally. More on this in a moment.
  4. Put the external content on the ArchiCAD layer. Why? So that it’s always visible. Since all your reference materials are in one isolated place, there’s no reason not to have them always on. Having them all on the ArchiCAD layer means less for you to manage. More on that in a moment as well. If you set the layer on the drawing tool before you drag and drop the content, you’ll save a step. So do that. You should save your typical Drawing Tool settings as a favorite, saving even more time on future projects.
  5. Use Trace & Reference to have the underlays show up wherever you need them. The easiest way to do this is right-click on the saved view in the navigator and select “Show as Trace Reference”.
  6. As more and more xrefs are placed, you need to deal with the ensuing clutter. Make a separate worksheet for each xref, hide each .dwg via layers, delete them, deal with ever slower regenerations times… OR set all the .dwgs and pdfs to ‘no preview’. This is my preference. Set the one you need to FULL PRECISION PREVIEW or quick preview. If you’re scanning through a few floors or related sections, you might find that you need 2 or more drawings set to one of the visible preview options so that you can check the content on both. Having all the drawings in one place makes this easy. And just like having them all on the ArchiCAD layer, having them in one centralized location is easier to manage than having them scattered about your .pln.
  7. Use the ‘Drag Reference’ option in the Trace & Reference palette to move the ‘underlays’ worksheet around as necessary. Since you placed the references a known distance apart, you can easily drag the Trace & Reference a multiple of that dimension to move between plans. For instance, if you set your floor plans 100′ apart, just drag the reference 100′, 200′, 300′, etc. to place the proper floor beneath the work you are doing.

BIM is about organization and making us work better. Look beyond schedules and 3D elements with embedded data. Your Building is a whole lot more than that. 2D external content is Information too. Manage it intelligently.

Want a little more information on importing .dwgs and .pdfs into ArchiCAD? Check out these two articles on the ArchiCADwiki: DWG import and PDF import. Also for further details on the Drawing Tool, check out this ArchiCADwiki article.

1 Comment

  1. Jared -

    Excellent article. I like your overall summary of options, and your innovative use of the single worksheet with multiple DWG drawings.

    I’d like to add a couple of notes. Each Viewpoint in the project will remember the last Trace Reference that was used, including the offset. This means that you can go to an Elevation View of your model and reference in a specific part of the DWG Underlay worksheet, aligned to match the model. When you go to a different Section or Elevation, they will remember their own individual references, so this works beautifully.

    However, all Stories are considered (in this context) the same Viewpoint, so the Trace Reference will not adjust to show a different background when you jump from story to story as you work on your project. In your solution, you have to manually Drag Reference the appropriate offset (e.g. 100′, 200′, etc.) to get it “in sync.” Another alternative would be to have multiple Underlay sheets for the floor plans, each one set for specific stories. That way one can simply switch the Reference in the Trace and Reference popup menu in order to get the right one showing under the model.

    I have a tutorial video on this subject – “How to Trace 2D Drawings to Quickly Create a 3D Model” on my ArchiCAD Tutorials YouTube Channel:
    http://youtu.be/gF2xY8sOn5Y

    In the video demonstration I show a number of techniques for taking advantage of the Trace and Reference function to quickly model a building based on DWG underlays.

    Eric Bobrow

    Reply

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