Site Plans

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Bill Wimberley
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Site Plans

I am working on a tutorial dealing with Site Plans. I will probably have it posted this weekend. In particular I will be dealing with how to draw site plans that have multiple connected curves.

Generally when I receive a site plan that I need to replicate in SoftPlan there may or may not be a curve data table. The curve data almost always shows the radius and length of the curve but rarely will it show the Delta angle for the curve. The problem is that SoftPlan does not have any way to draw a curve of a certain length. You can specify the length of the Chord that connects the two ends of the curve but not the length of the curve itself.

I have also created an Excel spreadsheet that will aid in the process. The spreadsheet calculates the Delta for the curve based on the length and radius of the curve. I will be showing how to use this information to accurately draw the curves so they are the correct length.

If anyone has any other site plan problems they would like included in the tutorial let me know.

Bill is the owner and maintainer of SoftPlanTuts.com

jimcrook@live.com
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Site Plan

Where do you find the time to do all the stuff for this site ?

 

I have done fairly limited Site Plan stuff but one thing I've wondered about is how you achieve a nice rounded ( curved, rolling ) 

look to the plan vs a very triangulated look.    I would typically set shot points at the corners of the site to get the overall rise or

fall of the site, but as I get around the building there is often fairly steep slopes as grade extends down say around a walkout

basement.   Even though I might place a fair amount of shot points I still find I get that triangulated sharp edged look rather than

a nice flowing grade.   In other words what I get looks more like trigonometry rather than geometry.  

How does one get that smoother looking flow ?

 

JimC

Bill Wimberley
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Grade Splines

Jim, try using Grade Splines as shown in this video. Creating A Site Plan

ChrisStewart
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Should make for an

Should make for an interesting article. 

Math is not one of my strong points but got me thinking about this problem because in the past I have just either had only one curve or have been able to obtain th full curve data table. 

 

I do not see where the delta would be useful in itself but it is useful for finding the arc chord

d=delta

r=radius

L=arc length 

ac=arc chord

 

 

d = (L x 360) / 2 x (Pi) x r

ac = 2 x r x sin(d/2)

 

Assuming that you also are given the bearing because if you are not given the bearing you would not know where to place the delta center point.  

But maybe you have an easier way. 

 

Bill Wimberley
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Delta

Knowing the Delta angle gives you a means to rotate a copy of a radius line and then use that to define the end points of the arc.

 

ChrisStewart
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Yes but that is an

Yes but that is an unnecessarily long way to go about it.

You can't define the arc center point without knowing the bearing and if you know the bearing and chord length and radius then you do not need to rotate a copy of the radius.

If you know the bearing and chord length than you enter the coordinate just as usual.

 

You example only works well when the center point happens to be perpendicular to the last known end point.  

   

Bill Wimberley
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Site

The subject of the tutorial will be to show how you would draw a lot such as Lot 1 below using just the information given. In this particular case the Delta Angle is provided so you wouldn't need to calculate it. But you would still use it to draw the curves. Many times the curve information would include only the radius and length of the arc.

 

ChrisStewart
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Good technique,

Good technique,

I can see how on most lots it is a good guess where the center point of the curve is. 

Bill M
Bill M's picture
IMO Softplan has improved the

IMO Softplan has improved the ability to draw site plans over the versions. They use to give me trouble but not so much anymore.  I don't draw them with elevation changes at all.  

Is there a reason it hasn't been improved to draw the length of the Delta?  I will be nice to have this chart to use Bill, thanks for effort on that and looking forward to the tut.  

Chris Stewart I don't know if this has been the same for you or not but I have found depending on the engineering firm that did the plat design, the coordinates don't always give satisfactory results and have to be tweaked to work.

 

ChrisStewart
ChrisStewart's picture
Yes that is true maybe 10% of

Yes that is true maybe 10% of site plan coordinates I receive do not form a closed site.

Usually within inches -could be a rounding error?

 

Standard rectangles are pretty safe. 

leglace
leglace's picture
Whew

Great, its not just me.

smiley

cbe
cbe's picture
I look forward to the

I look forward to the tutorial.  I am still working in that same subdivision from a few years ago where no 2 lots are alike and every lot as at least one curved property line.  I have a site bookmarked that will calculate the arc dimensions much like the spreadsheet you created.  It's helpful.  That would be a nice feature for softplan to add in future versions.

One thing that you could possibly include (or update your existing 'direction of north' tutorial) is a good explanation of the newer options and function of the direction of north since Softplan changed it for 2014.  I have figured it (or so I think), however newcomers may be able to get more use out an updated tutorial. I could be remembering incorrectly, but it seems that in v2012, the direction of north was handled on a per drawing basis.  Since v2014, it has been handled at a 'project level.  

 

While this is helpful for most situations, I wish I could go back to the 'per drawing' basis sometimes.  The subdivision I mentioned above has 50 unique lots and none of them have the same zero axis.  In 2012, I had a project that was just for the site plans.  B/c they are all small lots, I often needed to have each lot available to test a floorplan to see if it would fit for a client.  Each drawing had the zero axis correct.  Once I moved to 2014, each drawing reset itself to the project north.  Therefore I've had to add a note within the drawing on what the zero axis should be so I can easily edit it when the time came to use that site plan for a home.

- Cory

Bill Wimberley
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Tutorial delayed

I haven't forgotten about doing this tutorial. After announcing that I was going to do the tutorial I was made aware that SoftPlan had been working on an enhanced version of the "Enter Surveyors Coordinates" tool that would allow for drawing arcs using arc lengths or Delta Angles. I have been testing a couple pre-release versions and I wanted to see what the final version of this tool looked like so I could add it to the tutorial. Even though the enhanced version was not quite ready for prime time it was released in today's 2.0 patch. I'm going to hold off on the tutorial until they get it working properly. So I guess this won't happen until after the next patch.

Bill M
Bill M's picture
Bill will the patch be for

Bill will the patch be for v2016 or included in other versions as well?

Bill Wimberley
Bill Wimberley's picture
Patch

No, the enhanced Enter Surveyors Coordinates tool is a new feature added to 2016.

cbe
cbe's picture
I drew my first site plan

I drew my first site plan with multiple arcs yesterday since they released the patch.  It worked great for me.  It took me a minute to figure out how it worked, but it will save me some time compared to how I drew arcs in the past.  I could see some room for improvement, but it's definitely better than what we had in past versions of SP.

Jim Schuchmann
Jim Schuchmann's picture
Bill,

Bill,

First off - Thank you for this sight, it is amazing! I have been coming here for over a year and learning a lot. I am using 2014 so I do not have access to the new feature in 2016 for entering coordinates. I was wondering if there is any chance you might release the tutorial?

Bill Wimberley
Bill Wimberley's picture
Tutorial

Hey Jim. Honestly I had completely forgot about creating the tutorial. I have been so incredibly busy the past couple years I haven't even taken the time to do much at all on this site. I'll see if I can find a couple hours in the next week or so and put something together.

Jim Schuchmann
Jim Schuchmann's picture
I'm glad that your busy,

I'm glad that your busy, hopefully with paying jobs, 2006-2013 was brutal !

I would really appreciate it. Every time I have a lot with a curve I usually just have to fake it. Most plot plans in my area don't include all of the info needed.

Thanks again for your effort !

Slammer
Slammer's picture
I often am provided with the

I often am provided with the Delta, Length and Radius but I am still unsure of how to use that information to enter the distance and bearing like Softplan asks for. For example. L=195.39 ^=27 48 47 R= 402.5

 

How do I use this information to determine the bearing?

 

Bill Wimberley
Bill Wimberley's picture
Arc info

In versions prior to 2016 you could not use the length of the arc segment when drawing arcs. If you knew the arc chord bearing and length you could draw the arc by defining the end points and radius, but it is rare that I have ever been given that information. Many times people confuse the arc length with the arc chord length. Understanding exactly what all the parts are is key to drawing a site plan accurately. The Arc Length is the length measured around the curve of the arc. Arc Chord Length is the length of a straight line drawn between the two endpoints of the arc.

The Delta is the measure of the angle between two line segments that go from the ends of the arc to the center of the arc. So if you have one of the line segments you can get the other by making a copy and then rotating it by the delta angle. Typically, the center of the arc is perpendicular to the line that joins with the arc. This is because typically the arc segment is tangent to the adjoining line. So you can normally determine the center of the arc by drawing a line 90 degrees from the end point of the line segment and make it the same length as the radius of the arc.

In version 2016 you can draw arc segments by entering some combination of Arc Length, Arc Radius, and Arc Delta along with the optional "Tangent to Previous" setting.

In your example the L is the arc length. ^ is the Delta which is the angle between line segments drawn from the end points of the arc to the center of the arc. And R is the radius of the arc.