Xref, Dref, and Plotting

With C3D, it is an ongoing evolution on what to xref into your plot sheets and when to reference data into your plot sheets. It has been awhile since anything was posted about this so I thought I would share what seems to work the best.

First, I will throw a disclaimer in that each company’s needs and setup will be slightly different.

Second, I have added a simple flow chart so that you can visualize how the process works.


It seems complex but the most challenging part is changing our thinking of how we work just a bit. Let’s walk through a project.

  1. We have an existing surface file (considered a design file) and we DREF this into the existing topo survey file (considered linework).
  2. We do a conceptual layout. Since this is linework only, it is a linework file.
  3. We xref our existing survey and our conceptual linework into a new file where we create our proposed surface. We will also have to DREF in the existing surface.
  4. We xref our existing survey and our conceptual linework into a new file where we create our storm sewer drainage pipe network. We will need to DREF in our proposed surface (and probably our existing surface depending upon location and length of network).
  5. Now we begin creating our plot files. To create our grading and drainage plan:
  6. We xref in the existing survey and the proposed linework into a new file. We also DREF in the pipe network and the proposed surface. In this file, we label our contours, pipes, and structure in a way that the project can be permitted, constructed and built. We can even drop in some surface spots for good measure.

This may seem like a lot of steps but there are reasons to do it this way.

  1. Reduces file size, especially with keeping C3D objects out of drawings they are not needed in.
  2. Opens the opportunity for the engineer to still be tweaking the design while the designer is working on linework (parking stalls, easements, etc.) and setting up of the sheets (even throwing in labels for contours) without having to worry about the design being done.
  3. Gives the greatest flexibility for presentation. How you may want or be required to show alignment labels in your layout plan vs. your plan and profiles drawing can differ OR your contours, spots, and labels for your surface from your Grading and Drainage Plan to your Drainage Area Map or Erosion Control Plans.

Do you see the power of this setup? How much you put in the linework files, design files, and how much you break up your plot files will vary per company and really per project but you get the overall point.

Look at your project containing three different sections: Design, Linework (Layout), and Plot (Construction Plans)


  1. Steve Batchelder says:

    One thing you didn’t mention is when creating Cross Sections, you can xref your “design file” (which contains a corridor) into a “plot file” and create your sections in that separate drawing. This helps reduce the size of your “design file” especially if you have numerous cross sections.

  2. John Mayo, PE says:

    Excellent post Joshua. It’s overdue. We have evloved into the same practice. You may want to note for the surveyors that the same practice can be applied. It has worked well in our firm for surveyors and engineers. The only difference being the design files are now parcel and EG surface files.

  3. Kevin Clark, P.E. says:

    Setup is a key. http://images.autodesk.com/adsk/files/civil_project_mgmt.pdf is a good starting point.

    • That document was terrible when it was written, it still is. They basically took a Mechanical Engineering work flow (one object per dwg?) and tried to shoehorn it into the Civil space because it was coming from the Vault experts.

      While there is some practical information there in terms of commands I wouldn’t suggest that process to anyone I liked.

  4. Jeff York says:

    Good chart. Thanks

  5. […] is kind of an add-on to Josh’s post about Xref, Dref and Plotting. I just think it is such an important concept that I still see the […]

  6. Mikie van der Watt says:

    Do you do all the fine grading in step 3 where you create your proposed surface before you xref it into the G&D plan in step 5?

    • Josh might answer differently, but I believe that’s correct. That gives you a working design file that can continue to me tweaked and worked while sheet creation occurs in parallel.

    • Yes but let me take this breakout a step further.
      Your fine grading may include phases of grading. For example, your preliminary built on top of your site fine grading, which is connected to your corridor surface from the entrance drive.

      This is where it gets tricky in the sense that each company will see how to split these files up differently.

      So would you keep all design grading in one file or multiple files which are DREF’d into one master design grading file?

      This is where consultants help out.

  7. Mikie van der Watt says:

    I always keep my corridor and at least my storm pipework in the same drawing as my proposed or graded surface. That sometimes gets big depending on the size of the project. Its OK to have your sanitary pipework separate and bring in your proposed surface as a data shortcut because in itself it does not require grading. Then on the other hand you have your pipe networks in different drawings.

    Fact is that if you do not make use of referencing you have got a problem. I trained myself to use Civil 3D and have been upgrading workstations and complaining on the discussion groups for a long time before realizing that one drawing with 70-80 layouts and more than 200 viewports does not work and no system can handle that.

    I am looking forward to more posts on this topic.