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What should I ask a surveyor to provide in their DWG file?


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Does anyone have recommendations as to what deliverables to request from a surveyor in order to have a smooth import and DTM creation workflow in VW?   I typically work on single family residences, so the survey areas are relatively small.

 

@zoomer it looks like you've already thought about this.  Do you have specific things you ask for?  

 

 

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34 minutes ago, E|FA said:

Do you have specific things you ask for?

 

Not really.

I look at what I get and try to deal with it.

Last time I got a larger area as 3D Contours from the city and the site

as a DTM from the surveyor. Both where on different Z levels 😉

 

I am not sure what is really better.

Contours can be simplified before DTM creation.

But it isn't impossible to rectreate Contours from a DTM or Points

to do so later if necessary.

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1 hour ago, zoomer said:

I look at what I get and try to deal with it.

That's what I'm doing.  I'm working with a DWG file that has the contours with Z elevations, but all of the data points at elevation 0 (with actual elevation noted with text).  So the surveyor gets the points, converts to a DTM, generates contours, I take the contours and generate a VW DTM.  I assume there's a fair amount of rounding error in the process. If I knew what to ask for, I could probably get the original z-elevations to create the VW DTM.  Or, I can manually move 310 points to the correct z-elelvations.

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I ask for a "survey points file" in CSV format, which is a commas separate value file of all the survey point in a text file. Then it is rather easy to use the "Import Survey File" command to import the points into VW, creating stake objects that can then be made into a site model using the "Site Model From Source Data.." command. You need to specify the type and order of the information for each point: I use ID, Northing, Easting, Elevation, Description/Note. Tell the surveyor what order you want the information. Be careful of survey points that are not at grade. They can be stripped out of the CSV file prior to import or removed after importing.

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Posted (edited)

@E|FA I believe you should ask for a 'point plot' + then when imported the points are converted into 3D Loci:

1476003130_Screenshot2021-07-06at22_20_36.thumb.png.f89f65c164e1583040d65ef8b2114493.png

 

This way you're importing the exact levels/coordinates as measured on site without the information passing through any other process such as, like you say, interpolation into contours.

 

Although I say this having yet to be given survey data in this form: often like you I've been given a few token 3D contours but the bulk of the points in 2D which I've then either had to manually give Z heights to myself or try + get the data in .txt format, which brings it's own problems in terms of cleaning up the text before it can be imported.

 

I'm working with a different surveyor now how seems a lot more geared to 3D modelling, just waiting for first survey back off him...

Edited by Tom W.
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If the source 2D polys are evenly spaced there is also the 2D Polys to 3D Source Data command. You enter the height of the first poly (lowest) and the contour interval. Click the Next button to go to the next poly and it will automatically be one interval higher than the previous one. Or you can use the Higher/Lower buttons if you need to change the setting for that particular poly.

 

This saves you having to type in all of the heights.

 

Just another option is your surveyor is not helpful.

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I agree with @David Poiron.  Working with a text delimitated file is by far the most reliable, high function import you can use.

Contours and 3D polys from your engineer or surveyor are interpretations of surveyed points, better to start with the source data yourself.

 

I too edit the point file in a spreadsheet to break up the data set to what I need.  As long as your surveyor sends you their description codes, you can make quick work of filtering the points prior to importing the selected set into vectorworks.   I think this is the gold standard for building great site models and leads to the most stable vectorworks performance in my experience.  Plus, you can do math on the points, if required, to adjust points…. Example…lowering the elevation of points for a concrete driveway to account for its removal prior to your design starting.

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Thanks for the quick responses.  I asked the surveyor if he can provide a text file with points listed by ID, Easting, Northing, Elevation, Description in order to use the Import Survey File method mentioned above.  I'll let you know how it goes.  

 

I wouldn't have found this option without the forum.  I was looking into all of the File->Import options and never would have thought to look in the AEC menu for another way to import data.

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@David Poironsuggestion is the best option. I’ve done this myself and occasionally had to format the csv file to suit vw import but it is great to have the stake objects come into your file in exactly the right place.

 

I have sometimes separated the data into seperate csv files to import and class the stake objects as I go.

 

Its good to have a PDF of the survey for reference so you can see what should be where. 

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But is it not possible to import in 3D loci directly in one fell swoop + not have to process a .txt or .csv file first? The .txt files I worked with needed quite a lot of work to get them in a format VW was happy with. Admittedly a more helpful surveyor would have done this work for me but they were unwilling/incapable. And I've since been told about software you can use to clean up the text automatically which would have saved me doing it manually...

But im hoping to just be able to import points as 3D loci + have them classed according to whether they are terrain or structural or vegetation. Then is literally just a couple of clicks to make the DTM.

Also if you have a TIN based on 3D polygons presumably this is just as good as 3D Loci as each corner of each triangle represents a point? I've had surveys in this format too.

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UPDATE: The surveyor sent me a comma delimited text file with ID, Easting, Northing, Elevation, Description for each point, which I imported using @David Poiron's suggestion.  Oddly, it came in flipped vertically, but given the point descriptions I was able to align the property corners with a PDF underlay of the survey which I had already imported.  

 

Next up I'm going to see if I can set georeferencing and origins to work.  It looks like this should help:

 

 

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