Locate Your Building on a Plot Plan with SketchUpcomments (7) January 18th, 2012 in Blogs
Location, Location, Location
What are the three most important things for real estate value? Location, location, location. This time-worn adage applies just as well to builders and contractors. What with setbacks, easements, drainage planning, and other code compliance issues, it's important to get the location for a structure properly on the lot. There are plenty of ways to accomplish this but implementing the capabilities of SketchUp can streamline the process with a very respectable level of accuracy.
It's unusual to get a homework assignment before taking a class but its necessary in this case. Since most plat drawing line angles are given in degrees:minutes:seconds format and SketchUp (free version 8 at least) doesn't have that capability. It requires importing a "Ruby Script" to add the function. Even using a construction calculator to enter d:m:s angles and converting them to decimal angles doesn't help since SUv8 only allows three decimal places. I think it would take at least four spaces right of the decimal and probably five to be accurate enough. So the homework assignment is in SketchUp go Help>Learn About Ruby Plugins. Once you understand the process download this plugin: Survey Tool. After installing it you can find it under the >Tools>Survey Tool tab. As you watch the video you'll see how I access the Plugin and use it to create a plot plan layout from an acutal plat drawing I got from the local county courthouse.
I chose a random cul-de-sac plat for this tutorial to show the real "strength" of this process which is the ability to handle abstract angles and even a radius. While everything I show here applies to simple rectangular lots, I don't want to be accused of being a lightweight :-)
Do It To It
With the plat to follow and a PlugIn to work with I get about the business of creating the plot plan in SketchUP
In this video I create a random house footprint and place it on the plat. This is where the benefits of this process really kick in because it is virtually effortless to explore endless location options. Rotating the footprint, shifting it to any orientation, maximizing front, back or side yard sizes and distances and all manner of possiblities can be explored while SketchUp grinds out any dimensions you want to derive.
Extra Curricular Work
After creating the plot plan for this tutorial I was a little annoyed by the fact that the area calculation for the lot is shown in square feet while the plat drawing shows 0.8216 acres (select the lot area and go right click>Entity Info>Area). It feels hypocritical to proclaim the benefits of SU only to have to resort to a construction calculator to do a square foot to acres conversion, so I queried the SU Help Center and found this little Ruby Script to do the conversion for me. I learned that if you select the area then go Window>Ruby Console and paste this script into the box, it produces a text tag linked to the center of the selected area and shows it in acres. So if you download the Plot Plan model created for this tutorial from the SketchUp Component Warehouse you now know how I got the area to show in acres, not square feet.
I am NOT a registered/certified surveyor, not even an un-registered one, just a guy who's been around this stuff awhile like many of you. Taking this into consideration, apply any results you derive from this process using your own sensibilities. When in doubt, consult a professional, you'll both be glad you did.
Also, the calculations in this example are assuming a flat piece of real estate and DO NOT account for inevitable discrepancies that would be encountered on a sloped lot: the greater the slope, the greater the discrepancies. These factors could be incorporated into the process but that would be a topic for a more in-depth tutorial.
There You Have It
Hope this tutorial has given you at least a little food for thought for using SketchUp to expand your capabilities in doing plot planning for your own work or interest.
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posted in: Blogs, architecture, measuring and marking tools, foundations, driveway, plot plan survey setback
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