3D Model to See How High-Voltage Power Lines Impact My Property/Garden

Hi Sketchup Community

I am a newbie, so please excuse any dumb questions about Sketchup or incorrect terminology … and I hope I have posted this in the right place.

I have done an internet search to see what free software might allow me to create a 3D model of my property and garden and Sketchup came up in my search.

What I am trying to do is create a 3D model of my garden (nothing fancy just the a scaled model of the dimensions), then drop in my house and also a high-voltage electricity pole that is on the border of my property and the wires that cross the garden.

I am looking at extending and remodelling my house but the high-voltage power lines create a health & safety issue and I want to be able to model extensions to the property, changes to the roof or possibly demolish & build a new property within the garden footprint and be able to use Sketchup to understand the distances (x, y and diagonal) from various points of the property to the high-voltage wires to see if I have a health & safety issue.

This is the simple newbie question, will the free web version of Sketchup Web allow me to do the above?

If it can then a further question is will Sketchup allow me create a ‘no-go’ zone around the high-voltage wires so I can then take measurements (x, y and diagonal) using Sketchup Web to selected points in the garden so that I can understand what is in effect the ‘safe’ footprint area of the garden to re-build a property in?

Is the above quite simple to do (and for a newbie to learn how to do) in Sketchup Web?

Regards
Neil

It isn’t trivially simple, but not too difficult either, and well within SU’s capabilities.

If you could upload a simple sketch of your house and garden’s dimensions, and photos of the electrical pole, wires, and of your house, I might have a go at an example model. It would probably help to draw the wires correctly if you can show wires and one further pole on each side of the one nearest your garden.

I think I’d recommend using the free desktop version Make 2017 which would allow you to use a plug-in to draw the correct catenary shape of the power wires. It has very similar functionality to the free web version, but can use extensions - not available in the web versions. As this is for personal non-commercial use (as I understand your question) you would be ok to use this version. (All later desktop versions require a Pro licence.)

Once you have the wires correctly positioned, and can specify how far away from them is ‘safe’ you could use the FollowMe tool to draw a circular curved ‘tube’ round the wires to indicate where not to have your proposed extension or new building.

Hi John

Many thanks. I will create a sketch and provide some details of the electrical equipment. Based on my work may take me a day or so to pull together during non-work time.

Regards
Neil

Hi John

Please find attached diagram showing the property border and the house (a bungalow) position within the border.

The electricity poles and wire are shown in red. The height of the poles is 8m above ground and on the diagram I have shown a point where the cable height from ground is 7.3m. These are measurements that have been taken by the network power company. The electricity cable run has 3 cables, I would estimate 0.75m to 1m apart.

Please also attached 3 photos, showing Pole B, Pole C and a view of the cable run between them.

If any more information is needed then please let me know and I will do my best to provide.

Really appreciate you help and advice on this.

Regards
Neil

Forum wouldn’t let me upload as individual attachments so initially had did as sepate posts. Have now created zip file containing all.

Files.zip (3.0 MB)

Thanks. I’m busy much of this evening but will try and draw something late tonight (UK time) or tomorrow evening.

I’ve been able to have a quick look, and started a drawing.

I have a bit of a problem withy your dimensions, and am not sure how to resolve it.

It looks in your diagram as if the short ends of your plot are parallel, or very nearly so. And your diagram is not to scale, so I’ve redrawn it using the measurements you have noted.

But if I draw a 16m line at one end, and a 35m line at the other end, both at right angles to the 70m edge, the diagonal edge is only 72.5m.

If I extend it to 76m as your diagram suggests, it would make the ends very far off right angles at one or both ends.

Can you measure either diagonal of the quadrilateral to see how to fix this? Or else measure the angle at the lower right corner of your plot?

And also, the sag in the power wires is so small (0.7m over 64.5m) that I’ve approximated the catenary by a circular arc.

Here’s the model so far, saved back to v2017. You can open it in either the Free Web version, or the free Make 2017 desktop version.

Electrical wires.skp (2.6 MB)

The single wire I have drawn needs to be copied twice to represent the three parallel wires in the photo you attached. How far apart are the parallel wires? (Approximately.)

Hi John

Many thanks, this looks great.

The property border dimensions are taken from a plan that was from many years ago, I have converted to metres from feet. I would take the 76m as being more correct that any of the sides being at right-angles.

The measurements of the quadrilateral and angle will be difficult and I don’t really have the equipment to do. None of the 4x property boundaries are perfectly straight and I simply used the shape in the tool I did the drawing that gave the closest approximation. In reality the left, right and bottom sides are not that perfect.

All the measurements will have a degree of error. Particularly those that try to give the position of the top-right of property relative to the border, the same with those that try to give some guidance on pole B position relative to the house and the distance from the border where the wires cross the boundary.

The distances between poles were simply taken used ‘measure distance’ on Google Earth, so could well have some degree of error.

I would estimate the gap between each of the wires is 0.75m. I tried to see if could find a specification for these but haven’t so far.

Regards
Neil

Do you have anything like a hiking compass, or even a home-made ‘theodolite’, to estimate one of the corner angles?

The trouble is, that doesn’t of itself define the angle, just a range of possibilities.

Even a simple home made tool, like a school protractor on top of a stick, could get you a ‘good enough’ corner angle. Or even two pencil lines you sight along at the 76m and 35m corner.

Or two long straight pieces of wood you could place on the ground at the corner, approximately parallel to the 76m and 35m sides, then measure the angle between them?

Is the site approximately flat? If not, you may need information about the height of the ground at different places.

Roughly where do you think the new building or extension might go?

And what’s the minimum distance from the wires that you think would be safe for the nearest part of the new building to be placed?

Hi John

Many thanks.

I don’t think I will be able to get the angles you mention. I think the key aspect the diagram is the wires crossing the property and the relationship of the existing house and potential extensions or relocated footprint to it. The house (be that extended or rebuilt) would stay in the same area of the property as the current house. At this stage I am looking to analyse whether (and by how much) I can extend out towards the wires (north and west directions) or what the house footprint might look like if I rebuild the property moved in the south/south-west directions.

In terms of the minimum distance the power networks guidance is 3m. I would like to be able to model a range of zones from the wires from 3m, 4m, 5m and 6m, almost like a set of coloured bands that come out (i.e. almost like a heat map), but appreciate that may not be possible.

In terms of extensions or rebuild I then wanted to be able to model various options of house shape and height, which I was hoping that would be simple for me to just add, and the model to give me an indication of the proximity using the heat map.

Another option maybe that the height of the poles gets increased by the power network company so I wanted to be able to adjust these and then be able to understand the effects on the existing/extended/rebuilt house.

The ground is flat.

I accept that none of the measurements/angles are perfect and this was something to at least give me a feel for a few ‘what-ifs’ on what was possible in terms of extension or rebuild. Once I get to that point I then have a further set of decisions to make and if need be to refine the modelling.

Regards
Neil

Well, here’s a bit further development of the model.

I drew 3, 4 and 5m circles round the ends of each of the three wires, then took the outside of all three to represent the different clearances you might want to use.

Then oriented the plane of the circles at right angles to the start of the centre wire, and used FollowMe three times - once for each clearance radius.

That gives a good representation of the ‘tubes’ outside which you would want to build.

But there’s still a large uncertainty about the position of the wires in relation to the house.

You showed a distance of 13.7m between the pole and the side of the house, but as originally drawn, it’s only 13.2m. I positioned the house parallel to the angle in your sketch.

If I were to rotate the house about the corner 14m from the plot edge to make it 13.7m from the pole to the house side, it would need to rotate some 6.9°.

Like this:


Electrical wires.skp (2.7 MB)

No time to do more at the moment, but think about how you can more accurately relate the position of the house to the centreline of the wires. You need one or two angle measurements for the plot edges, to correctly position the 76m edge in the drawing, and/or measurements from both corners of the house to the base of pole B and to the plot perimeter.

Hi John

Many thanks, this looks really great. Really appreciate the work you have done.

On the 3x wires, then it is the outer wire nearest to the house that at this stage is the key in terms of provding a basis to measure 3m, 4m, etc outwards to the house.

How can I pick up the above as an actual file(s) so can play around with in Sketchup and FollowMe? Is this relatively straightforward for a novice to do? Is is relatively straightforward to add further circles at 1m intervals?

I want to be able to look at the effects of:

  • Extending the property say on the left-end (so moving towards the wires on as they flow from Pole B to C) and also extending towards Pole B.
  • Moving the actual house footprint downwards (so towards the 70m boundary if that makes sense) and then being able to see how that affects distance I have to the wires and possibly also how the height of the property may have more space to increase.
  • On either of the above get a rough basis of clearance distances (hence the thought of the circles/heat map).

As per previous post at this stage I am simply trying to understand my options for the house (accepting degrees of error), so can either make or at least dismiss some options. If any options I have still have viability then I can look at refining the model or make is part of a task that I would want an architect to be able to as part of a design stage.

Once again, really appreciate the help you have given on this. The above already looks to have surpassed what I expected at this stage based on the limited and accuracy level of the information that I have been able to provide.

Regards
Neil

Download the .skp file I uploaded above.

I’ve already done that for all three wires, and for 3, 4 and 5m clearances.

Sorry but I really have to go now. More later if it helps.