Handle the Bag: Cul-de-Sacs and Parcels

How do you do parcels around a cul-de-sac?

This is a quite common question. I used to get bombarded during those notoriously straightforward straight road demos with cries of "BUT THAT ISN'T REAL. WE DO A LOT OF CUL DE SACS" followed by "I hate Civil 3D" and "Civil 3D Sucks".

Well... I do cul de sacs, elbows and other weirdness with Civil 3D parcels all the time. This is just a way that I have found works.

There are many other Autocad and Civil 3D tools that can be combined to make a good cul de sac.




This works in both Civil 3D 2006 and 2007. Don't forget The Parcel Rules .

THE PARCEL TOOLKIT

There are a bunch of AutoCAD commands I like handy when doing a site plan. So I made a Tool Palette for them. Making a custom tool palette is super easy. I am a customization MORON and I can handle this.

If you aren't familiar with toolpalettes, they are SO EASY it hurts.

There is a pdf paper in the Files Area of the Cadapult_Civil Yahoo Group that you can download that will take you throught making a custom toolpalette. Or check out HELP or the New Features Workshop under HELP.

You have to be a Cadapult_Civil Member to get that paper, but everyone is welcome to join. You just need a yahoo login. http://groups.yahoo.com/group/cadapult_civil

REMEMBER- ANY CAPTURE CAN BE ENLARGED BY CLICKING ON IT!


Yes, there is a ROW parcel tool under Parcels Menu. But I don't like it. It works OK for simple stuff, but it is too hard to edit the result. I like to make my ROW and Back of Lot target parcels from polylines.



Use regular offset to offset your aligment. The resulting offset lines are polylines.

I make a circle for my culdesac.


Fillet and trim as necessary around Cul De Sac and intersections. You have to explode the polylines in order to fillet to circle.


I like to join all the lines to prevent leaky buckets. It also gives me a chance to erase the whole ROW at once later if I want.


Once they are closed and tight, define them as a parcel.


Here is my starting point. I leave the back of lot target rounded for now.


I like to make perfectly sized lots along the first stretch.










Then, since my lot width is measured from the building restriction line (40 ft in this case) I offset my ROW with a little guideline. You can change the frontage in the parcel layout tools to a lower frontage number if you know what works.



There are a few ways to confirm and get your frontage. This is just the way I am doing it now. Other ideas include making a BRL parcel and a BRL site, then laying your parcels out there with min. frontage and using that result as a guide.

I like to break my guideline at point, then use the lengthen command (which also shortens BTW) to see where 75' is.


Then I grip edit my attached parcel segment.



If the width is good, but the lot is too small, I can add another segment.



And erase the perpendicular to ROW segment. Using the parcel edit erase button, I can erase one segment at a time.


To square up the rears when I am done, I draw a new segment (or acad line then create from objects) then erase the arc using the parcel edit tools.

After a few iterations and adjustments, I wind up with this: