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:
Friday, July 07, 2006
Posted by Dana at 5:34:00 PM