Being Civil

Project Blocks to Surface and Assigning Elevations

I have been meaning to write about this for a while now but for some reason the timing was pretty bad for me every time the thought crossed my mind....until, my colleague Phil (our Map 3D guru) asked for it. He’s got an issue where a user had a drawing with hundreds of points represented by blocks. These were not COGO civil points and they had no Z values (all were 0.00). His goal was to find the elevation for each point. Luckily he had a valid Existing surface. So basically he wanted to project his “points” to the surface. Here is how that can be done.

First let’s confirm that our blocks don’t have correct elevations by going into object’s properties

 

2. Select our Existing Surface and from Contextual ribbon expand Surface Tools and pick “Move Block to Surface”

 

3. The next dialog should pop-up showing available blocks. Let’s select our Tree and Utility Pole blocks

 

4. Finally, let’s check the object properties and confirm that our block now have some elevation values gotten from our surface

 

Note: This is also useful if you want to use visualization tools and use multi-view blocks during rendering. Also, you can then create Civil Points from it if necessary. Procedure is explained in this link: Convert Point Block References to Civil Points

 

Why My Corridor Surface Contours Are Not Displaying Correctly

By now we all know that Corridors and Corridor Surfaces are dynamically linked and that changes would propagate as soon as your corridor or surface used as target in corridor is changed. However, there is one exception to that rule which could cause some possible trouble. That is if surface object is locked.

How do you know if surface is locked? Well, in prospector tab you should to see  icon (lock). To demonstrate one issue that you may encounter, take a look at the contours in the image. You will notice that the contours are kind of sticking out, right? To give you more confusion, you the cross sections may be showing the modifications you have made to the assemblies but the proposed contours are not updated correctly.

 

Quick Tip: Creating Surfaces from Point Clouds

Why are all the points from my point cloud not being used to generate the surface? We receive this question fairly often from users who are working with Point Clouds and want to create surface from them. This is due to a few different factors, and the first thing to understand is that Civil 3D creates the surface from the points that are displayed. So that means if only 1,000 points are displayed, that is what is used for the surface creation.

Now there are some additional options you need to pay attention to in order to fully understand the results you are seeing. Civil 3D has a limit of 1.5 million points displayed at one time. If you are zoomed all the way out on your entire point cloud of 5 million points, only 1.5 million will be displayed at one time. Another thing to pay attention to is the Point Density Slider which will control the display of the points as well. So if you want your surface to take in as many points as possible you will want to move this slider to 100.

All that being said, adding all these points is usually not necessary as they are not all needed to accurately represent the surface with the TIN model. Not to mention the file size may become quite large when dealing with that many points added to a surface.

Corridor Surface Contours Not Matching Target Surface?

You may have noticed that occasionally when creating your corridor surface that the contours from the corridor surface sometimes do not "match up" as expected. Contours will never “perfectly” tie in because contours are not the TIN, they are an approximate representation of the TIN. We are modeling surfaces, so it performs an exact match from edge of TIN to edge of TIN.

As you may have noticed in your corridor some places can seem worse than others. This is due to the frequency set in the corridor parameters. A very wide frequency will cause the surface creation to interpolate between those intervals, and if the terrain varies quite a bit between those frequencies, the interpolation can produce less than desireable results. Although the results appear to be incorrect, it is just Civil 3D doing the best with the information provided. The trick to resolving this issue is to shorten the frequencies in these areas and you will see your contours begin to tie in to existing ground much better.

Moral of the story: tighter frequency=tighter contours

The fodder of this post was obtained from a conversation with the one and only Jason Hickey. Thanks Jason!

AutoCAD Civil 3D 2013 New Feature: Survey Query

One of the new and cool features introduced this year are the additions to the Survey functionality. Survey Query tool can be used to filter points and figures from Survey database by their properties. Since survey data is stored externally in survey database, it can be brought or referenced into a drawing-we all know that by now. Survey Queries now allow us to filter by any of the survey properties listed in either general or extended properties defined by user defined properties or brought in via LandXML.

One other thing you may notice when building a Survey query is the Survey ribbon that allows us to not only create new queries but to also insert them into the drawing or add them to the surface. It looks like this.

In survey tab you will see a new node “Survey Queries”, right-clicking on it will bring you to the Survey Query Builder.There you can name your query, add criteria and even preview it or save the query. So let’s see how to create one simple query out of points with description containing SDWK value. For lack of better idea, let’s say our goal is to filter all points defining our sidewalks. 

AutoCAD Civil 3D 2013 New Features: Check TIN for Max Angle

Now that we started slicing and dicing new features in AutoCAD Civil 3D 2013 one feature caught my eye. In Surface Properties, Definition tab, there is a setting that does pretty similar task as “Use maximum triangle length”. This one is found right above it. It’s called “Maximum angle between adjacent TIN lines”. What does it do, you may ask? Well it is basically set to analyze and build surface more intelligently by eliminating TIN lines that exceed desired maximum angle. To see more, click on continue reading.

AutoCAD Civil 3D 2013 New Features: Surface as a Hide Boundary

One of the new features added to Civil 3D 2013 is the ability to select surface and use it as a boundary for other overlapping surface. This one is not easy to explain so I will use one of the possible workflows to describe where you will most likely end up using it. At the same time we can review the workflow about adding boundaries. Two birds with the same stone, kind of a deal. Pay attention on step 4 but let’s go one step at the time.

Here is the scenario: When we created a corridor surface and tied it with Existing ground (EG) surface we often want to see how it all ties together. DRIVE command is very useful tool here because it shows us how the road looks and it looks pretty on the screen. But if we invoke DRIVE command we may see that there are some bumps along the road. These bumps are basically showing those cut areas from our Existing Ground (EG), so the corridor will be obscured here. The gray thing that looks like gray cloud is basically my quick rendering of Existing surface. It looks like the road will get into EG-not good!

You may choose to hide EG, and that’s OK- you can see the entire corridor, but you will not be able to see where it ties into Existing Ground. See how and what after the jump.

AutoCAD Civil 3D 2013 New Features: Surfaces in Volume Dashboard

For quite a few years, we have been able to compare two surfaces (existing and proposed, for instance) and get some cut and fill values. Volume Dashboard takes it a step further because it allows you to break down your surfaces in phases or for some particular area of your concern such as a lot (parcel). Basically any kind of closed polygon defined as boundary will do.

Volumes dashboard gives us a tool to calculate multiple volumes for a corridor surface, or a surface that lies below multiple parcels. It also calculates volume for the entire object. For example, if you have a corridor design that is broken into phases, you can calculate the volume’s cut/fill for each phase and also put it all together or combine to see what your Phase 1, Phase 4 and Phase 5 have while leaving out Phase 2 and Phase 3.

Another scenario that is documented in help (there is a video too) talks about having 4 parcels and driveway on top of the surface.

Not only that but it gives you an opportunity to adjust cut and fill volumes and factors for specific areas as you change it-in real time! From there you can create a report or paste the calculation in your drawing. Volume Dashboard command is found in Analysis ribbon. Create Volume Surface in Dashboard by comparing two surfaces (EG and my Top corridor surface).

 More about it after the jump.