Takeoff Layers and Layer Groups - Best Practices

I am often asked how many layers and layer groups should I use to separate out data. I am also asked which methods to use after importing CAD or Vectorizing data to separate out the data. I carried out a deep dive into best practices and have come to the following conclusions

When you import CAD data or vectorize a PDF file you get layers of information that are in the default Layers Layer Group. At this point the layers are named as per the engineers naming or if vectorized from an unlayered PDF then the layers created are based on object types (lines, text, fills) and then based on styles (lineweights, colors, text styles, fill styles / hatch patterns etc.) Bottom line - this data is separated out as good as it is going to get without additional work.

One thing that we asked Trimble to add to the properties pane is the ability to add or modify the selected objects layer group. The benefit of this is that you can select a single object of data on each different layer and change the Layer group of those objects to e.g. Existing or Design and by doing so you move all the data from those layers into the new layer group. This is actually regrouping the source data layers into target groups.

To line up with this great feature, I suggest creating a Layer Group called 00 - Existing Source Data and 01 - Design Source Data and then you can simply select one or more objects that represent existing or Design features and then change the Layer group property to 00 - Existing Source Data or 01 - Design Source Data group. You can turn off these groups so you can see what data remains in the Layers Layer Group and then continue your selections etc.

Once you have the data separated as Source Data Groups - you can then review all Existing or all Design layers by turning off / on those Layer Groups.

Now you can work on each layer in turn to clean it - use Smart Join to join lines. Use Break to Break lines. Select and relayer linework to separate it from other data on the same layer to get your contours separated from everything else.

Ultimately for a Takeoff you probably will end up with 3 layers for Design

  1. Design Contours
  2. Data Lines (3D lines to be used as site improvement boundaries)
  3. Data Lines (3D lines that are model breaklines but not Site Improvement Boundaries i.e. Grade Breaks etc.)

You will likely need a layer for a grading limits boundary and another for overexcavation, and I would think that (2) above will be used to bound landscape areas for topsoil replacement.

For Existing you will have similar for

  1. Existing Contours
  2. Data Lines (for Demolition Site Improvement boundaries)
  3. Data Lines (for 3D model breaklines not to be used for site demolition boundaries)

Then you will have your Source Data Layers for Design and Existing, your residual data layers in the Layers group and then other key layers for Site Data (Boreholes, Site Improvement Markers, Image Boundaries etc. and other key Takeoff layers for e.g. Erosion Control, Areas of Interest and Cut Fill Map labels and legends etc.

I will post a video this week to show visually what I am recommending here as a process.