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mpkeane

Cut and Fill Calculations

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Hello;

I am hoping to do some cut and fill calculations on a landscape design. I have the existing contours on one layer (2D plan view), and the proposed new contours on another layer (also 2D). Is it possible to add elevation information to the contour lines and have VW do cut and fill calculations automatically?

Marc

Mac OS 10.6.8

VW 2010

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Hi Marc

You need to create a Site Model. Here's a brief summary of the process:

You'll need to convert both sets of 2D contours into 3D Polygons and set their Z value to their respective heights.

Select the contours that relate to the existing site and choose Landmark > Create Site Model. Complete the dialog and click OK.

Now, select your proposed contours and add them to the class Site-DTM-Modifier. Select your model and choose Update.

Then, you can choose Update Cut and Fill calculations on the Object Info palette.

Good luck!

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Thanks so much for the clear explanation Tamsin. I'll give this a try.

Marc

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You're welcome - as I said, it is a very brief overview of the process you need to follow, but it will set you in the right direction.

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Anyone know how to export those numbers to a worksheet, rather than copy and paste them from the OIP?

Also, I was under the impression that 3D polys didn't have to be in the DTM-Site Modifier class.

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Hi

Yes - Tools > Reports > Create Report. Create a report based on the Site Model record and choose the fields you want to include in your report. That will list the information you need in a worksheet.

The 3D Polys that you use as source data do not need to be in the Site-DTM-Modifier class, but as Marc has already drawn his proposed contours as 3D Polygons, he will need to put those in the Site-DTM-Modifier class to get them to behave as modifiers on his site.

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Hi Tamsin;

Things have worked about halfway I think.

I placed the 2D contours, existing and proposed, onto 2 separate layers

I made each contour line (both existing and proposed) into a 3D polygon and assigned a Z value to each

I selected all the existing contours and created a site model of those (Landmark > Create Site Model). A model was made with a boundary line.

There was no class called Site-DTM-Modifier so I made a new class with that name (hyphens included just as you wrote) and assigned all the proposed contours to that class. The existing contours are in another class and the Site Model of the existing contours is in the class None.

I selected the site model of the existing contours and clicked Update in the Object Info palette but nothing happened. I clicked Update Cut and Fill calculations on the OIP but still nothing. No data for cut or fill.

In the OIP, there is data for Projected Area (existing) and Surface Area (existing) but the Projected Area (proposed) and Surface Area (proposed) read No Proposed Site.

Question, when I made the Site Model, under 2D display settings, should I have chosen Existing Only, Proposed Only, or Existing + Proposed?

I think the problem is this "No Proposed Site" but how can I fix that?

Thank you.

Marc

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Is the file huge? If not, you're welcome to send it to me and I'll take a look for you. If it is huge, we could set up a shared dropbox folder.

tamsin@vectorworks-training.co.uk

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Guest

Ive noticed a correlation between large files and incorrect Cut and Fill quants...Marc,I suggest you do checks and balances using spreadsheets

How do you check your quants Tasmin?

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The file is very small. I extracted on the contours from one section of a larger design to do a test run on the cut & fill calculations, so the whole thing is tiny. I'll email it to you.

Thanks in advance for your help.

Marc

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OK I had a look at the file. I had forgotten to explain that your model also needed a Boundary (created with the Site Modifier tool). However, I couldn't get the model to work and when I copied the source data into a fresh file, it wouldn't make a model at all. So, here's what I did:

1 Take the source data (original contour) 3D Polygons and ran the Simplify 3d Polygons command to reduce the number of points on the polys a little.

2 Ran 3D Polys to 3D Loci to convert the Polygons to 3D Loci.

3 With these Loci selected, created a new site model.

4 Copied your 3D Polygons representing proposed contours from your file and pasted them in place in the new file.

5 I then made sure they were in the Site-DTM-Modifier class.

6 Then, on the Site Model, I made sure 2D Display was set to Proposed.

7 I clicked Update on the Site Model and it updated beautifully.

8 I clicked Update Cut and Fill Calculations and it worked.

Hope that helps! Good luck with the rest of the project.

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Hmmm am I the only one that checks Cut and Fill Quants?

Guess it doesnt matter if all we're talking about is a couple of trailer loads->$100,in one case VW was out 250,000 m3->$1 millon (Badluck)

"Leader in Site Design" is a bold statement any comments (your tube Video) from NNA?

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I have been able to get partway through this cut and fill calculation process:

? convert contour lines to 3D polygons

? make a site model from the existing contours

What I don't understand is how to identify the proposed contours as such. I put them in the Site-DTM-Modifier class but when I select the site model made from the existing contours and click Update, nothing happens. The OIP reads "No Proposed Site"

Is there a user manual for VW 2010 that has a detailed description from start to finish on how to do Cut and Fill calculations? The VW Help system is not very helpful in this regard.

Marc

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Hello Tamsin;

Sorry for the late response ? I was away for the weekend.

I'm afraid I did not receive your email with the screen-shots. Could I trouble you to send it again? info@mpkeane.com

I really do appreciate all the help.

Marc

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LOL, Tamsin, I know you meant "re-sent", but I still chuckled when I read "resent" because it was so totally out of character. You are certainly one of the least resentful people I have ever known ;-)

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Tamsin;

Thank you, again, for all the time you are spending on this. I'm afraid I still have three problems.

1) I still do not have a clear idea on how to do a cut and fill calculation from start to finish myself. I have been able to create a site model from the existing contours, but I cannot understand how to signify to VW which the proposed contours are. Do they need to be on a separate layer? Is assigning them to the class Site-DTM-Modifier all that is needed? Isn't there a user manual that describes in detail how to do a cut & fill calculation? It really seems to be needed.

2) When I opened the VW file you sent back to me, the Cut and Fill data was just as shown in the Screen-shots you sent: Cut = 37820 cu ft, Fill = 9788 cu ft. When I clicked Update and then Update Cut and Fill Calculations, however, VW comes up with an entirely different set of numbers: Cut = 7994 cu ft and Fill = 7886 cu. ft. Why would the calculations be so wildly different on my computer and yours?

3) If you look at the existing and proposed contours in my drawing, you will see the re-grading design I did is almost entirely Fill. Your calculations showed a net of 28,000 cu ft cut. My show a net of 128 cu ft of cut. Both are obviously very wrong.

Is VW 2010 actually dependable for doing cut and fill calculations?

I will try making a simple grading plan in a new file and see if (a) I can actually do a cut and fill calculation and (b) if I can get some reliable data.

Thanks again for all your help.

Marc

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Tamsin;

Is VW 2010 actually dependable for doing cut and fill calculations?

Marc

The short answer NO!

and the user wouldnt know that unless you get into the habit of checking the DATA- Your credibility is at stake,mate-HTH

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Marc

The "triangulator" within Vectorworks's site model changed significantly between versions 2010 and 2011, so you will see a difference. My screenshots are from 2012. I will explain the process in more detail later... in a meeting right now.

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OK Marc to answer your questions:

Here's an overview of the process:

1) Prepare your source data (the existing site). This can be 3D Loci, 3D Polys or Stakes.

2) Select the source data and choose Create Site Model. This is the existing site.

3) Use the Site Modifier tool to create a Boundary - this limits how much of the site should be updated when you make changes.

4) Now, add further site modifiers. Pads will create flat areas or new contours. 3D Polys or 3D Loci can be added to the Site-DTM-Modifier class and they will become modifiers. So, any modifiers that are not the source data (that we prepared in 1 above) will be seen as the "proposed" site.

5) Select the Site Model and click Update. Change the options on the Object Info palette to see existing site or the proposed site. 6) Click Update Cut and Fill Calculations to see the cut and fill.

However, Building Design Consultant makes a good point about cut and fill calcs. There were significant changes made from Vectorworks 2010 to Vectorworks 2011 in the triangulator engine within the site model. I have done tests by building a known and constant slope and then created cut and fill that is easy to calculate outside of Vectorworks, and I get extremely similar results in this simple model. However, it will also be affected by the quantity of source data. Vectorworks will connect up the source data points and create triangles from it. If you don't have enough source data, remember that a lot can happen across the site in reality so there will always be small inaccuracies. In Marc's case, he is using Contours for both source data and proposed changes. Contours are "interpolated" data, and, depending on the circumstances, you may also need to include specific spots heights if you are protecting certain features on site.

I hope that helps explain the process a little better.

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Tasmin,

A couple of questions:

CAn the DTM-Site Modifier class be further amended and still show up in the site model, such as "DTW-Site Modifier-Proposed" or "DTM-Site Modifier-Pad" and put in the same layer? Could all proposed go in another layer and then check to use all layers or all visible layers? Still not sure from your answer how you distinguish ex and prop.

Also, what (in 2012) is the maximum number of points a site model can efficiently handle? I work on big sites (golf courses) and have heard varying numbers, but seem to recall a maximum of 10,000 points before it gets boggy.

BTW, my draftsman tells me that 2012 really seems to handle the DTM better than even 2011 and certainly 2010, so there seem to have been some "under the hood" changes to Landmark in the last two versions.

Thanks.

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Hmmm am I the only one that checks Cut and Fill Quants?

Guess it doesnt matter if all we're talking about is a couple of trailer loads->$100,in one case VW was out 250,000 m3->$1 millon (Badluck)

"Leader in Site Design" is a bold statement any comments (your tube Video) from NNA?

Have you filed a bug report on this issue?

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Yes - significant changes "under the hood" since 2010 which all help with accuracy in calculation, but as I said in my earlier post, quantity and quality of source data for the model will also affect the results when compared to the real world site.

In terms of Existing and Proposed, once you have created the model from the "source" data from the survey, this becomes the existing site. If you need to add any further information to the site, you can right-click it and choose Edit Source Data, which enables you to add source data. You then no longer need to have modifiers for the existing site in your design layers. So, there is no need for a method of distinguishing between existing and proposed. Existing is embedded within the model.

Other modifiers relate to proposed changes.

I will use different design layers for different types of modification, and set the model to visible layers only, so I can a) review the effect of certain modifiers in isolation and b) explore different design options, simply by making design layers visible and invisible.

I don't have an answer on the number of points I'm afraid. I've had issues with large sites that are created from very curvy 3D polygons, where there are an unnecessary number of points along the curve. This can cause things to slow down. But you can run Simplify 3D Polygons to reduce the number of points along the poly before making the model. I prefer to use point data from the surveyor instead of existing contours because they are the accurate measurements that were read on location and have not been pre-interpolated.

Hope that helps

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