Site Line Offsets

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Last post's picture
Site Line Offsets
SoftPlan Version:
2014 Plus

On a Site Plan what is the proper way to offset an irregular shaped lot frontage ( i.e. water frontage )  to establish the setback line ?  

In my experience you can't really just offset the frontage line in it's entirety due to it's irregular shape you actually end up with 

different setbacks at various points along the line.  In other words due to the irregular shape not all parts of the line are being moved

at a 90 degree angle.  Alternatively if you try to offset individual parts of the line at 90 degrees you change the shape of the line. So

how is it typically done ?


Jim C

Bill Wimberley
Bill Wimberley's picture

It looks to me that offset works just fine. I just offset the site polygon.


Bill is the owner and maintainer of

yvongonthier's picture
Spline property line

He might be using a spline property line which offsets differently than the lines?

Bill Wimberley
Bill Wimberley's picture

Hmmm...I've created tons of site plans over the years and have never used splines for the property lines. Typically the property lines are made up of explicitly defined straight lines and arcs. The arcs can get a little messy when offsetting a distance larger than the arc radius. But Fillet cleans them right up.


Bill M
Bill M's picture
I use the offset command also

I use the offset command also and to connect/clean up the lines I use the fillet tool.  I did have and instance not long ago where the offset was going to the opposite side that it was suppose to and Bill W knew of the problem and told me how to handle it.'s picture
See Attached Example

I have attached an example of what I'm talking about.


You can't just take the front property line ( shoreline ) and block copy it back the setback distance you want

because that won't really give you the actual setback to the structures that you want due to the various angles involved.


Trying to offset a polygon or even individual lines at 90 degrees each works great in a large lot but in narrower lots the

setback lines can actually by-pass each other to the opposite side and/or when you fillet the lines the resulting setback 

is not really the shape of the frontage line at all.


I've done both on the attached example. In one case I just block copied the frontage back 20 meters to see how it would

relate to the buildings and in another case I copied each line back 20 meters at a 90 degree angle for each and try to

fillet together what makes sense and erase the by-pass lines that are not longer relevant to the setback.


I just wondered if there was some logical way to deal with developing this curvy and angled kind of setback line without

havaing to copy all the individual lines or arcs and filleting as best you can ?  If I try to offset a polygon it just ends up with

a series of circles due to all the lines gong too far past each other.



Bill Wimberley
Bill Wimberley's picture
SoftPlan Drawing

Can you attach the actual SoftPlan drawing rather than an image?