Civil 3D Blogger Day – My Notes

My notes so far:

What’s covered: Subscription Advantage Pack, End of the week goal to get content out.

Point Cloud Support

“Bring site visit home with you”

Roundabout Layout

French market already has this tool.

Wizard included to layout the roundabout. Has a graphical representation of the different settings in the wizard. Both internal alignments and the flares entering the roundabout. No vertical design. Drag entering flares to see if the roundabout fits to see if additional right of way is required.

Visualization and Analysis Tools

Site visibility tool. To see if a driver can see an obstruction, a green disk.

Drive, select alignment, or feature line, it follows the profile of an alignment. Goes through the design, kind of like the cross section viewer for corridors, except you get the full 3D view of the surroundings.

Green arrow can see, red you can’t see. Line from road to a surface. The dragging uses a surface elevation.

Sight Distance Along Corridor. Works on both on Design Surface and Existing Surface. Magenta shows issue, green shows the design is OK.

Zone of Vertical Influence. Wind towers and cell phone towers. Green see all of it, Red can’t see it, Yellow can see part of it.

Transportation Productivity Tools

Alignment Tools

Create Best Fit Alignment: point groups or alignments. Can have two alignments, such as left and right sides. True curve and tangent.

Create Alignment from Existing: Road rehabilitation work applications. Split an alignment up.

Survey Production Tools

Zoom to Point capability

Edit figure database while in the drawing, move points around in the autolinework creation. Join, break survey figures, reverse all or part of a survey figure, create a survey figure in the drawing. Curve break, to create a compound curves, no need for a small tangent.

Miscellaneous Feature Improvements

Divide/crop surface (create subset to share into other drawings). Making smaller surfaces. Select cropped surface. The master surface changes reflect in cropped surfaces. Cropped edits don’t get pushed back to master surface.

Create surface from GIS data, takes the SHP file and assigns the elevations. Define area of interest by polyline. View with FDO for a preview and then bring in area of interest. Assign the correct elevation field from the GIS file. No data link from the SHP file to the surface. We’re the ones changing the GIS data.

Minimum vertical distance between surfaces, to find the distance between the roadway and the bridge. The zero elevation gives a drawing object for a daylight line.

Other items.

Language versions.

To be installed on Civil 3D 2010 (SP2)

Probably to become integrated into Civil 3D from the Toolbox and maybe other tools available .

Can call commands from the Toolbox, so each one has a command. Can create a ribbon, but has a short life.

Plane on a Treadmill

The Mythbusters on the Discovery Channel did an episode in 2008 regarding an airplane on a treadmill/conveyor belt. The myth as stated on the official discussion board of the show was:

"A plane is standing on a runway that can move (some sort of band conveyor). The plane moves in one direction, while the conveyor moves in the opposite direction. This conveyor has a control system that tracks the plane speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction). Can the plane take off?"

I enjoy watching the show, but sometimes I wish they’d add an engineer Mythbuster to draw some free body diagrams or inform them that there is better testing equipment available then making their own contraptions for testing strengths of materials. This episode sure could have used an engineer or physics professional.

 

I was thinking about the episode on my way down to Southern California this weekend and figured they didn’t test the myth, but they created their own myth.  In the episode they took a long length of fabric, put an ultra light airplane on it. A truck was attached to the fabric and pulled it at the takeoff speed of the plane.

You’ll notice their goal was to have the fabric match the takeoff speed of the airplane, which they did. To satisfy the myth the fabric would have to match the speed of the plane, which it didn’t. When the Mythbusters tested the myth the plane accelerated to match the speed of the fabric and then kept accelerating until it reached the takeoff speed.

In exploring the myth they took a RC car and put it on at treadmill to show matching the speed of the car and treadmill would have the car be stationary on the treadmill.

 

If you take a look at the forces involved we’ll notice that the force from the engine is transferred to the tires. The main concept to look at is the what friction provides in the relationship. Friction is what allows the tire to rotate on the treadmill and match the rotation of the treadmill. If the tire and treadmill didn’t have any friction the tire would spin and not go anywhere, regardless of the force the engine of the car applied.

In this case I’m looking at the front tires, since my car is front wheel drive. The force of the tire matches the force of treadmill keeping the car stationary. Since the front tire is the driving force we need to look at the rear tire to relate it to the tire of a plane. The both the rear tire of the car and the tires on the planes see only external forces applied to it. The speed of the tire will match the speed of the treadmill because of the force of friction. If there was no friction the tire would stay stationary. If I increased the coefficient of friction of the rear tire it would make the tire go slower, causing the engine to have to apply more force to the front tires in order to stay stationary on the treadmill.

If we take a look at the free body diagram of the plane’s tire we’ll see that the tire sees the force of the treadmill and the propulsion forces of the plane. The force of the treadmill is transferred to the tire through friction. If the friction force is greater than the force of propulsion the plane will move backwards. If the friction force is less than the force of propulsion the plane will move forward.

The tire will go as fast as necessary to reflect the forces applied to it. As the mythbusters provided in their video if the speed of the treadmill matches the takeoff speed of the plane it will take off. That is because the propulsion of the plane is greater than the friction force applied to the plane’s tires.

In order to get the plane to stay on the treadmill we have to either make the plane weigh more to make the force of friction match the plane’s propulsion (which wouldn’t be preferred since the takeoff speed of the plane would be increased or the area on the wings would need to be increased to provide additional lift to keep the takeoff speed the same) or increase the friction coefficient by changing the treadmill/tire surfaces. The easiest way to test it would be to increase the coefficient of friction of the tire/treadmill interaction. Unfortunately I don’t have a plane or treadmill to test out the theory. Maybe the Mythbusters will try it out in a follow up episode.

Adding Multiple Boundaries to a Corridor Surface

Occasionally you may want to add multiple surface boundaries to a surface. If you try to add multiple surfaces to a corridor for the corridor properties you will discover that only one boundary may be applied at a time. A way to get around this limitation is to add the boundary directly to the corridor surface outside of the corridor properties.

The first surface will be an outer boundary and each additional boundary will be a show boundary.

Here’s a short video: http://screencast.com/t/4Pg3FNLAsW3

Running .NET from a Network

Running a vb.NET dll from a network in AutoCAD doesn’t work very well on it’s own. It appears, at least from my small sample size, to work as long as the code doesn’t use Windows Presentation Foundation. If the code utilizes a routine that AutoCAD runs with WPF, AutoCAD crashes indicating that the routine isn’t supported. Unfortunately prompting the user for information such as a number or object causes this crash.

A way around this is to use the LispFunction available in .NET. The LispFunction passes a ResultBuffer between the .NET routine and a LISP command. By utilizing a LISP routine I was able to avoid the WPF issue. The LISP routine gets any objects or numbers required from the user and then passes them to the .NET routine. The first code I created worked fine on Civil 3D 2008, but crashes Civil 3D 2009 & Civil 3D 2010. I suppose the AutoCAD API was revised to use WPF after AutoCAD 2008. I then had to resort to using the LispFunction.

For more information on how to use the LispFunction check out these AU Papers:

CP211-3 VB.NET Command School

DE211-2 The Best of Both Worlds: .NET and LISP Can Coexist

Both papers may be found at AutodeskUniversity.com or AUGI.com.

Civil 3D 2010 Swap Parts Part II

In a previous post I introduced the ability to swap parts for pipe objects. It is also possible to swap structures. The structure of the code is almost exactly the same as the swapping pipes as shown below.

In the above case I’ve gone through and moved the code to vb.net. I’ve also added coded to allow the user to select multiple pipes and structures and added a dialog box to have the user select the pipe and/or structure from a dialog box (most of the code is not shown), no more having to change pipes or structures one at a time.

This short video shows it in action: http://screencast.com/t/MksgtRgeBuHS

If you want to try it on for size you may find the compiled project here: http://style.civil3dreminders.com/C3DRemindersPack2009-10-12.zip

Instructions on how to load it may be found here:

http://style.civil3dreminders.com/civil3dreminderspack