IMAGINiT Civil Solutions Blog

Five degrees of separation

Arc->SHP->Pipe network.

Last week I posted on how you can export plines to a SHP file and import the SHP back as a pipe network.

If in your geographic area, your pipes can be set to straight line assignments within the ROW of a curved road, than this is not an issue

 

However, if your pipes are to follow the curvature of the road, you may run into a few snags. After creating a SHP file of a curved pipe pline and importing it back into civil 3D, you will get the curve represented in segmented cords. Cleanup will then be necessary

Yes I realize that, essentially in the real world, stock pipes come in straight segments. However to simulate a curve we install the pipes with the allowable deflection to closely follow the curve.

        

The cause of the issue of the lost curve in a shape file is because, SHP do not support true parametric curves, including circular arcs, ellipses, and Bézier curves, so these shapes are stored as straight segments.

Using a trial and error method of creating a number of different curves and exporting and importing from shape file. It seemed the common denominator between all the curves, is the deflection or the central angle. No matter what radius or curve delta angle I used, the deflection angle was always 5 degrees. However if the curve delta angle was not a multiple of 5, then the last deflection would be the remainder

But what determines the cord or segment lengths. I have not been able to get an official response, however, as in most road design calculations, it seems that degree of curve may have been the premise of the calculation in the Mapexport to SHP. I love math formulas and here is a great explanation http://mysite.du.edu/~jcalvert/railway/degcurv.htm.

So why 5 degrees and can this be changed. Well apparently it can. In the C:\ProgramData\Autodesk\C3D 2015 folder there is a file MapExport.ini that contains the settings. This file can be opened in notepad. Currently the setting for the angle, although it is set to 5, has been commented out with a semi-colon (;).

What this also leads me to believe, is that unless specified otherwise, the default angle is 5 degrees.

 

To change, simply remove the semi-colon, change the angle and save the file.

 

However, if you want to use a cord distance instead of segmentation degree, enter a positive value for FME_ARC_CHORD_DISTANCE

When positive, the arc-chord distance will override the SegmentationDegrees, ARC_DEGREES_PER_EDGE.

and the next time you run the “mapexport”, the settings are extracted from the MapExport.ini file

 

 

 

Just a Pipe dream

How do you efficiently create a pipe network in a land development project?

Typically in my geographic area, as in most others, we are governed by utility line assignments that follow the road right of way.

 

However, the tools that we are presented with, in C3D assume that we will utilize the transparent command to place manholes based on alignment and offsets. And that my friend, is like using chopsticks to bait a hook with a worm. It can be done, but is a ……….

It would be safe to say that it is easier to use the AutoCAD offset command to draft up the sewer lines and then, either trace over using the pipe network creation tools or convert the polylines to a pipe network. However the tool to convert a pline to a pipe network, only allows you to select a single pline. To address a land development project similar to the image above, you will have to then merge all these single networks into one complete network.

Three years ago I started and partly completed a dot net program that would allow a user to select a network of plines to create a pipe network. I never did finish the program to make it fool proof (so any fool could use it) to be political correct error checking.

Anyway last week, as I was working on a project to import GIS data, I believe I may have stumbled on a solution that may not require me to write an application.

In concept.

• We will draft our sewer lines using offset,
• export to a SHP file and then
• Import the SHP file to create a pipe network.

Draft pipe layout

1. Draft a network of pipes using the AutoCAD offset command.
2. Use MAP3D “cleanup tools” to break lines at intersection i.e. where two pipes connect

Export to SHP

1. To export these In C3D, at the command prompt enter “Mapexport”
2. Change the file type to SHP and enter the name of the output file
3. Object type is Line
4. In Select object export. You can select manually or by all. Select all object that represent your sewer lines. At the bottom of the dialog you should verify the number of selected objects.
5.  As we have simply drafted lines without any intelligent data we do not need to utilize the options within the Data tab.
6. Click OK to create the SHP file. As a side note if you wish to insert symbols as manholes you could do that as well and follow steps 1-6. But at step 3 object type will be point

Import GIS pipe data

1. In C3D on the insert tab, in the import panes, in the drop down list select “Import GIS Data”
2. Select the SHP file (or files if you also created a SHP file for manholes). Select the connect button and the next button
3. Set all you options for your pipe network in the Object Options dialog and select Next.
4. Set the Schema and coordinates. In our case we do not have a schema. Select Next.
5. In the Data mapping select a C3D pipe shape and click add
6. You will see the pipe attribute assignment populated with the attribute fields that are defined in the selected pipe shape you selected in the step above. If in the drafting phase and the export phase you created pline without any intelligent data i.e. object data you do not need to do any mapping and can simply select Next. If however you data contains intelligent data you can map the intelligent data from your SHP file to the C3D pipe attributes.
7.  As we only had dummy down data that does not define the size of sewer lines, we are now prompted with a message. Select Use the default shape attributes. Select Next
8. If you have created a SHP file for manholes or structures you will have to go through a similar process as steps 5-7. Select Next
9. In this next dialog, Query options, you choose to import all or create a query to select specific pipe or structures. In our case we may want the Import all. Select Next
10. If additional drawing cleanup is necessary. i.e. set a snap distance between a structure and pipe, or delete dangling pipes or structure that are not connected to any pipes.
11. Select Finish.
12. You should now have a complete network drafted up. Some cleanup is also necessary as structures are not inserted at the intersection points but not the end points. Also, additional structures are inserted along a curve. After the manual cleanup using C3D as a design tool you can simply enter in slopes and inverts.

 

This could be an interim solution. Well, at least until Autodesk realizes the need to either provide us with an offset command for drawing a pipe network (similar to what AUD has) or have the ability to create a pipe network by selecting more than a single pline.

Multi view blocks, a different perspective

Last week I posted on how to create and utilize multi view blocks within C3D, and for the most part it has some value when viewing designs in 3D. This week I tried pushing the envelope just a little further and attempted to utilize multi view blocks within a civil 3D profile view.

It seems that this is not as simple a process as I had hoped or anticipated. A multi view blocks does not change to an elevation view in a Civil 3D profile view. This could be the simple fact, that similar to LDT, C3D’s profile view is simply a visual representation of the elevations in a 2D plane. It is not a 3D elevation view. As a result the true functionality and intention of a multi view block will not work in this regard.,

So what is……, yes, that dreaded word “workaround”. What you need to do, is also create an associated elevation view of your multi view block. This new 2D block will be used as a style in your profile view. Needless to say, not ideal.

Hyd_M is my multi view block that I will use in my point style that displays perfectly in plan, and 3D views.

    

   

Hyd_P is my 2D block that will display my elevation view of point object that is projected onto my profile view.

            

Hope this workaround helps. Well that is, until Autodesk address this wish list item.

 

On a different note. On a new vehicle or a rental, ever wonder which side of the vehicle the gas tank cap is located. 
Well if you look closely at the gas pump icon on the fuel gauge there is an arrow indicating the side.

 

 

Multi-view Blocks

A multi-view block is an AutoCAD block that can have different representations in different view directions. Incorporating multi-view blocks into a Civil 3D model is a great way to prepare your design for visualizations

For example, the top view of a multi-view block representing a Hydrant shows the 2D symbol. The bottom view shows the bottom of the Hydrant, and there are representations for left, right, front, and back views. You can have one set of views for plan view and another one for 3D view.

 

AutoCAD Civil 3D contain a large number of predefined multi-view blocks for a number of design purposes. These contain multi-view blocks of building footprints, landscape symbols, annotation symbols, site-related symbols, and other useful elements.

            

You can access these multi-view blocks from the AutoCAD Civil 3D MV Blocks Tool Palette.

    

Creating Multi-View Block

Creating a MV block is simpler that you may think. What you need are two symbols or blocks one in 2D and one in 3D. Below are my two blocks for a street light. The left symbol is a 2D symbol and the right is a 3D.

      

Create a Multi-view block to hold these two blocks.

1. In the C3D at the command prompt enter _AeccMvBlockDefEdit or in the AutoCAD workspace, insert tab, block panel, in the dropdown select edit Multi-View block definition.
2. In the Multi-view block definition
1. Select the new button
2. enter the name of the multi view
3. Set the Multi-view block component to 2D or 3D
4. Select the add button to select the block
5. Select the appropriate block based on step 3 i.e. 2D or 3D block. Note the view panel to the right
6. Select the apply and OK button when done

        

To insert a MV block in C3D enter _AecMvBlockAdd at the command prompt, or in the AutoCAD workspace in the insert tab, block panel, in the drop down list select add multi-view block

To use a MV block in as a civil 3D point maker, as a point marker can only use a standard AutoCAD block we will have to create a block that contains the MV block we created. Similar to a nested block

1. Define an AutoCAD block, from the Insert tab, block panel, select the create command. Give your block a new name, and for objects that will define this standard block, select the multi view block you created.
2. Now in C3D in the point style you will have access to this standard block that has a MV block imbedded.

Here is a video that will walk you through the process.

https://www.youtube.com/watch?v=3J8I2jSku_k

Importing SketchUp files into Civil 3D

Nicholas Edwin | Solutions Consultant

I’ve had several users, who’ve finally decided to adopt BIM workflows into their project processes. One of the first questions they ask is, “how do we import early stages of our model into Civil 3D?” They were using SketchUp in the very beginning and didn’t want to recreate the data. They also wanted to insert the SketchUp models onto the terrain surfaces, to show a very conceptual 3D view of the design.

 

Civil 3D’s 2015 version have adopted an add-in tab located on the ribbon where plugins can be installed. Theses add-ins give Civil 3D some extra functionality, like opening/handling proprietor formats like SKP files. One of the add-ins that can be executed is called the “Import SKP”. By selecting the “Import SKP File” command, user can select a SketchUp file and interactively place them in the drawing.

 

Keep in mind, manually scaling may be necessary to get the model proportional to the true scale of your terrain. Materials can also be viewed if the realistic mode is used in Civil 3D visual styles selection.

Enjoy……

Getting projects started using the set location command

Nicholas Edwin | Solutions Consultant

In the past, getting started on a Civil 3D drawings/project required some base data acquisition. This base data was used to determine where the site was located and from there, users could determine the coordinate zone, then the process begins. Which means, users will have to download aerial images, world files and insert them using the map insert command. A convert/re-project of the base files to the drawings coordinate may even be necessary when working with multiple coordinate systems. This process can take some time and since the majority of new projects will use aerial images in some shape or form, this can be a somewhat tedious task.

             

Civil 3D’s new features streamlines this process and allows users to get a head start on this process. There are some prerequisites that are required before getting started.  Users’ needs an Autodesk 360 account to allow for the use of this new tool. A coordinate system should be assigned to the drawing or template. Also an internet connection is required to stream data from the Bing map servers. Once the user has an account and logs in, the process begins. Login can also be done by selecting the “set location” command which automatically triggers the sign in screen. Additionally the information center, located in the upper right hand corner of the screen, can be used to sign in before starting the “set location” command.

 

Once logged in, clicking on the sign in button automatically opens the geographic location dialog box. An address can be used to pinpoint the site location.

 

Two intersecting roads can also be used to help pinpoint the site location. The last method can be a manual panning and zooming to the desired site location.  The user can select the road or aerial view option to display the map using the Bing map image servers. By clicking on the drop marker button, it allows for the dialog box to advance to the next option which is where the available coordinate system for the local area are all displayed. Once the coordinate system, time zone and unit of measure are selected, the location maps are now applied automatically. This is just another way users can implement a workflow for getting started in Civil 3D.

In the previous version of AutoCAD 2014-based programs while we were able to view the maps within a drawing you were no able to print the map data/image.  In 2015 Autodesk has introduced a capture function which allow the user to create an inserted instance of the image that can be printed.  

Enjoy…

Data format, DWG or GIS

Given that AutoCAD was released in 1982, this relates to a massive amount of digital information that has been created over the years. In the area of Land development or utilities, the selection of choice of data format for a majority Autodesk clients is the DWG format. For the most part on smaller projects this may be manageable however on larger projects that may span a number of years, managing massive dwg files becomes awkward.

What is needed is a streamlined process of design and data management that reduces errors, is model based, supports 3D visualization and simulation, and is capable of sustainable workflows

With the growing popularity of GIS and the increasing availability of a wide range of datasets, GIS is becoming a common tool for all disciplines. GIS can be a useful tool for analysis of landscape changes and trends, and can help managers and the public visualize resource conditions and the consequences of proposed management actions. (Interestingly enough Autodesk's newest flagship consumes a variety of GIS data formats)

 A CAD drawing element contains only the information needed to draw itself – coordinates, lineweight, linetype, color, and the layer to which it is assigned. GIS, on the other hand, has an additional functionality- its features can hold enormous amounts of data describing the features. Simply put, CAD is a drawing, and GIS is a spatial database

In many ways CAD and GIS are like oil and water. The CAD people see their work as real world constructability, engineering-based with high precision placement and accurate measurement. They view GIS as neither precise nor accurate. The GIS people on the other hand see their work as larger scale and cartographic in nature rather than pure engineering.

So how do we use CAD and GIS in what they are best suited for. The solution would seem to be that, it would be prudent to use CAD to do the real world design and convert the as built data so that it can be consumed by the GIS.

There are a number of tools within Map3D and Civil3D to do these conversions. In Map3D in the output tab, data transfer tab the DWG to SDF command or (_mapdwgtosdf) will allow to convert your existing CAD data to a variety of GIS formats.

In Civil 3D if you are outputting to anything other than a SDF file, the process is more involved.  You cannot export C3D objects directly to a varity of GIS formats. You will first have to export to an SDF file by going to the output tab, in the export panel, select the “Export Civil Objects to SDF” (_AeccExportToSDF).

 

Next you will have to import the SDF file. In C3D at the command prompt enter "_mapimport" or switch to the "Planning and Analysis" workspace. In the insert tab, import panel select the Map import command. Import the SDF file you just created, all the feature data will be intact.

 

Next using the Map3D command (as shown in the previous paragraph) export to any of the other GIS data formats.

Another tool for exporting CAD data to GIS that is absolutely worth exploring is FME by SAFE Software .

I was impressed with the product. Here is a short video worth viewing. https://www.youtube.com/watch?v=of4LLn_C5I0

Given that some CAD users have invested a huge amount of time leveraging out of the box tools like linetype, color, text or layers to identify different features, FME impressed me in how it was able to convert this data to spatial data. Example FME is able to take pipe text labels in a CAD drawing and create feature class.

Something to think about data management, DWG or spatial data file. Which works best for your application in the long run.