In your BIM process, you spend a lot of time modeling geometry, coordinating your design with other trades and generating construction drawings for field layout. If you are like many other contractors, you would like to be able to relay the accuracy of your CAD model to the field without doing additional work in that process.
The Trimble MEP Robotic Total Station (RTS) can help you accomplish this task both quickly and accurately. Using tools that are already built into PipeDesigner 3D from QuickPen, I will show you how to get your coordinated data from the CAD model to the Trimble MEP RTS.
There are several types of points you can extract from your CAD model to the RTS. Hangers, wall penetrations, sleeves and control points are a few of the items we can locate in the field, based on our CAD geometry.
We are going to cover three basic techniques that will allow you to create point data for the majority of your work, and bring the hard work and time you've spent in the coordination process to the field. Integration of the RTS into your BIM process will make your field layout faster and more accurate.
Creating a CAD layer for RTS Points
For this example, we will create three CAD layers that onto which we can place our respective points. They will be: A-Gridline-PTS, M-Pipe-Hngr-Rods-PTS, M-Pipe-Wall Penetration-PTS. To create these layers, I used the layer of the geometry for which I wanted to supply a point, and added a '-PTS' to the end of the name so I will have the ability to isolate that layer as needed.
Creating Control Points
Control points are important for RTS set up so it knows where it is located on the job site. General contractors should provide these for each floor as it is constructed but you will also want the ability to create your own in the event the GC's aren't available.
For this example, we want to freeze all layers except for the layer of the gridlines and its respective point layer (A-Gridline and A-Gridline-PTS)
- Select Insert Object Points from the PD3D Tools ribbon. The Insert Object Points Dialog box appears.
Enter the following items in the Insert Object Points dialog:
- Under 'Entity Types' check lines.
- Under 'Field Point' type a description of Control Point.
- Under 'Field Point Location' check the box that collates with where you want the point to be located. In this case At Intersection.
- Under 'Field Point Elevation' select 'At fixed Elevation' from the drop down box. This will give you the option to enter in a fixed elevation in which we are going to use zero inches.
- Under 'Field Point Layer' select 'On fixed Layer' from the drop down box. The layer that you want to select A-Gridline-PTS. (If that layer is not populated in the list you may have turned it off when isolating the gridlines. Layers need to be on and thawed out to be visible)
- Under 'Attributes' we can assign up to five.
- Attribute 1 description; Column
- Attribute 2 description; 3' Offset
- Back at the top of the dialogue box you have two buttons from which to choose. The first, 'Select Entities', allows us to pick individual objects on your drawing. The second button, 'Select Entire Drawing', will automatically select all the visible layers in our CAD drawing. For this example choose 'Select Entire Drawing' Button because we have previously isolated only the layer we want to put points on.
After you select the Entire Drawing Button you will notice that Under Entity Types the geometries have been populated with the number of objects found pertaining to that piece of geometry.
- From here double check all your information is correct and click on the 'OK' button at the bottom. The dialogue box will close and your points will be automatically populated in your Auto CAD drawing at each intersection.
If you remember in attribute No. 2, we used a 3' offset. We can now physically move those points in the appropriate direction by selecting them and physically moving them in CAD. This location will have previously been determined by your design team and/or the General Contractor.
Inserting Hanger Points
For this example, we want to place a rod point at the bottom of all our allthread rods. We want to freeze all layers except for the layer that the allthread rods are on and its respective point layer (M-Pipe-Hngr-Rods and M-Pipe-Hngr-Rods-PTS)
- First, make your 'M-Pipe-Hngr-Rods-PTS' layer current.
Then in an isometric view use the 'point command' in Auto CAD to snap a point at the bottom center of each piece of allthread.
- Once complete, isolate the 'M-Pipe-Hngr-Rods-PTS' layer with all the points on it that you just created.
- Next, go to Pipe Designer 3D tools ribbon. Select Insert Object Points.
The steps are going to be similar from above except for the following:
- We want the 'Field Point Elevation' to be the same as where we snapped the point instead of at a fixed location. This elevation will be relayed to the RTS and show where in your coordination process you have set the bottom of that piece of rod. This is beneficial if the bottoms of your rods are at different elevations. Also, we can give an attribute description of '1/2" Rod', information that will be beneficial to the site layout team.
- Select the Entire Drawing Button and the number of objects found pertaining to that piece of geometry will be populated.
- Double check that all your information is correct and click on the 'OK' button at the bottom.
Note: back in your CAD drawing your points that you created will not be visible in an isometric view. You need to switch back to a plan view to see them.
Creating Wall Penetration Points
For this example, we will place wall penetration points on a piece of pipe that will penetrate a wall. We want to freeze all layers except for the layer that the pipe is on and the layer we are going to put the wall penetration points on (M-Pipe-CW-Supply and M-Pipe-Wall Penetration-PTS). We also want to leave the wall layer on for visual reference.
- First, make your 'M-Pipe-Wall Penetration-PTS' layer current.
- Draw a line at the center of the pipe that extends about 2' on either side of the wall. It is important that the line extends past the wall so the RTS can better locate the center line in the field.
- Once you have lines on all the pipes that will be penetrating walls, freeze the layer that the pipes are on.
- Go to Pipe Designer 3D tools ribbon. Select Insert Object Points.
The steps are going to be similar from above except for the following:
- We want the 'Field Point Elevation' to be the same as where we snapped the point instead of at a fixed location. This elevation will be relayed to the RTS and show where in your coordination process at what elevation that pipe penetrates the wall.
- Also, we can give an attribute description of the pipe size and how big of an oversized hole will be needed.
- In this instance, we will use the 'Select Entities' Button and you will be taken back into the CAD model where you can select the lines you created. Once you select your lines and hit 'Enter', it will take you back into the dialog box and you will notice the Entity Types have been populated with the number of items you selected.
- Double check that all your information is correct and click on 'OK' button at the bottom.
Exporting Points for use with the Robotic Total Station
Now that we have all of our points created we need to export them for use with the RTS.
Now you can navigate to the folder that you named in the export and notice that you have created both a points file (.mep) and a background file (.dxf) for the Nomad. Or for the Tablet, a points file (.tfl) and a background file (.dwg). You can now load these files onto your respective data collector and start laying out points in the field.
- First isolate your CAD layers that you created points on.
- Then, under the 'Trimble MEP Export' button you have two options for export. If you have a 'Nomad' collector you will select 'Trimble MEP Export', if you have the 'Tablet' collector you will select 'Trimble Field Link Export'.
- The first example we will use 'Trimble MEP Export'.< >Fill out the 'Trimble MEP Export' dialog box as shown.
Verify the directory and file name and then click the 'OK' button.
The Second example we will use 'Trimble Field Link Export'
Fill out the 'Trimble MEP Export' dialog box as shown.
Verify the directory and file name and then click the 'OK' button. You have successfully exported point data to your Robot Total Station.