AutoCAD 2010: Polylines

I've decided to blog some more about AutoCAD 2010 and ignore Civil 3D 2010 (probably for the next two months). One of the new features I think is cool and will improve productivity is the following two features (taken from Between the Lines):

• Polylines can now be sub-selected i.e. segments of plines (also called as sub objects) can be sub selected using CTRL key
• Users can sub select the segments of Polylines during 2D editing commands such as move, rotate etc.

It's kind of hard to read those two features and get what you can actually do with it. So in this post I'm going to explore what you can do with these new features. First as the feature says you can select a sub object or multiple sub-objects of a polyline.

I was thinking it would be cool to select the segment and delete it, but you can't. You can grip edit one of the grips and when using the stretch grip edit it moves the whole segment keeping it as the same angle and adjusting the adjoining segments.

So in the above picture I'm extending the line to the right using polar and the two adjoining segments are getting longer. As the feature list indicated the other grip options also work as shown in the picture below.

I've just shown the new feature with one segment selected. You can also grip edit more than one segment at a time. For instance in the picture below I've extended the vertical lines to the west of the previously modified segment to the east.

You can even select segments from two different polylines and modify them. Hopefully you can see why I think this is a good new feature in AutoCAD 2010.

So why no Civil 3D 2010 related posts? Because I think I should test drive the new feature before blogging about the feature. I have confidence you can read press releases or view videos and me blogging about the features that I don't really know about doesn't benefit me or you. I currently don't have access to Civil 3D 2010 and don't expect to get it until the free trial download is available. I do have access to AutoCAD 2010, so that's why I feel comfortable blogging about those new features.

BE Communities

I did do a few posts in the past regarding Microstation, I did learn some of the program but I never did get much work to do with it. Some people in the office did get to do some work with it, I just wasn't one of them.

I did get an email from Bentley regarding recently regarding their BE Communities site. It has a bunch of information regarding their products. It seems a lot easier to find information about the products compared to the last time I looked for stuff. They even have a place to create a blog, although I probably won't be using since you can't link to an outside site.

Forrest Gump was a Good Movie

"Yes, Mom if everyone else was jumping off the cliff I would also" and with that said I'm going to go along with the marketing blitz and mention that Autodesk announced that AutoCAD 2010 has been released. Not quite sure what released means since you can't yet purchase the program. I guess it means that the masses can learn what's in the 2010 version without worrying about a non-disclosure agreement (NDA).

I'm not sure but the blurb in the press release regarding Civil 3D looks like a typo. I'm thinking it should read AutoCAD Civil 3D 2010 AutoCAD Civil 2010, it looks like the marketing folks are even confused on the versions of the program.

"AutoCAD Civil 2010 AutoCAD Civil 2010 adds a variety of feature enhancements that help civil engineering technicians, drafters, and surveyors complete projects faster including a streamlined user interface, a more complete field to finish surveying workflow, and roadway intersection modeling."

I have seen AutoCAD 2010, but haven't seen much of Civil 3D 2010. The roadway intersection modeling looks intriguing though.

Since I do a lot of posts regarding VBA, it's interesting to see that the AutoCAD product won't be shipped with VBA installed. VBA will be available as a download though. I'm don't know if Civil 3D will be shipped the same way.

The parametric tools look promising and I've done a little experimenting with them. I think they may be helpful in revising a portion of roadway, but probably wouldn't work very well to add them to a whole subdivision. Well I guess I should explain what parametric tools are. It's kind of like partbuilder with an easier user interface, just kind of kidding. You are able to have AutoCAD constrain objects to one another. For instance you can make a an arc portion of a polyline remain tangent to the next line portion of the polyline. The images below show two polylines that have parameters applied. Grip editing the top polylines top rightmost grip will adjust the parts of the polyline and the lower polyline.

Before

After:

To quote Forrest Gump, "That's all I have to say about that."

Slope Ranges

In the last post I provided a link to a site that had the formula, in relatively simple terms, to figure the slope of a TIN triangle. Civil 3D uses the formula (or a similar one) to draw a water drop path or shade the TIN triangle based on the surface's slope analysis style. On thing you can't do in the surface style is exclude portions of a surface that are under a certain area. Some municipalities require an exhibit showing of all slopes within a certain range, but more than a given area value. For instance they may require showing slopes that are greater than 25% and more than 500 SF in area.

By using Civil 3D's API it is possible to extract the information from the surface to create the required exhibit. The OutputTriangles method for an AECCTINSURFACE object contains all of the points that make up the TIN. By taking the points that make up the triangle's one can use the formulas to calculate the slope of the triangles. Once the triangle slopes are known, the boundary's of the triangles that meet the slope range can be merged into a boundary polyline and then checked to see if it meets the minimum area.

The link below contains the program that I came up with to do the task. The program only works in 2009 and completes the task at hand really, really, really slowly. The slowness is in the code and could be optimized. The code portion of the dvb file is password protected, but feel free to use the program if you like. The program hasn't been fully checked and may contain bugs, so please check the output. The way I checked it was setting the style of the surface to show the same slope range and then checked to make sure all of the big areas had polylines around them.

http://style.civil3dreminders.com/SurfaceSlope.dvb

Calculate the Slope of a TIN Triangle

This link: http://geoinformatics.sut.ac.th/sut/vichagan/AdvanceGIS/3_TerrainMappingAnalysis.pdf

Combining pages 31 & 34.