Advance Volume

[rsalastopografia]

Good afternoon dear community, I turn to this forum in search of help on a topic related to advance volume by the surface comparison method. In the file I have 3 surfaces (1. Initial land surface, Design surface and progress surface in work) and I need the appropriate procedure to obtain a precise volume by the mentioned method, in such a way that when calculating by sections it returns the same data. Currently, the company with whom I collected data requests that the surface purchasing method be applied to obtain volume measurement. Below I detail with images:

In this image cut from a longitudinal profile we can see 3 lines (corresponds to the initial surface, design and advance) and a fill hatch, I want to obtain my advance volume (red line) by the surface comparison method which is It makes it complicated for me with 3 surfaces.

In the following image cut from a longitudinal profile we can see 3 lines (corresponds to the initial surface, design and advance) and a cutting width, I want to obtain my advance volume (red line) by the surface comparison method taking as data 3 surfaces. Additionally, I was wondering if in 3D civil, using the surface comparison method, I can obtain measurements only of cutting and independently of filling, or in any case what would be the appropriate procedure in this case to obtain my volume and that it does not differ with the cross-section method? . I hope you can read my case and provide me with the timely help; Greetings, Attached Dwg file.

[Joe-Bouza]

I see your concern. Can you share the supervision’s methodology for computing the volume?

[Joe-Bouza]

I see your concern. Can you share the supervision’s methodology for computing the volume?

[Joe-Bouza]

Maybe this will help

Google “Civil3d surface volume accuracy “

I tried pasting for you but my phone won’t 

[teerawat.pSCHYQ]

Hi @rsalastopografia  basically surface comparison analysis in Civil 3D are 100% accuracy. as you only showing result volume from your side and from  supervision, I believe if you and supervision used same surface in base surface and comparison surface, the result will come same. Now we don't know your comparison step by step and supervision comparison step by step.

[fcernst]

Yes.. a Composite Volume surface gives separate Cut and Fill volume totals with optional Cut and Fill factor capability. You need to make your section sampling distance very small for the approximate section methods to more closely approach the surface Composite comparison volume method. 

[rsalastopografia]

The supervising designer used the surface comparison method, previously carrying out another process, and described how to make an accurate calculation.
1. By comparing the initial terrain surface vs. the design surface, I generate polygons independent of the cut areas, then I do the same to determine polygons in fill areas (there is a command to generate polygons with 2 surfaces).
2. crop the initial and design terrain surface independently with the cutting polygons I previously extracted.
3. crop the initial and design terrain surface independently with the fill polygons that I previously extracted.
4. Once the 4 surfaces are obtained, the comparison is made as follows: initial terrain surface (cut) vs advance surface, initial terrain surface (fill) vs advance surface, design surface (cut) vs advance surface, design surface (fill) vs advance surface.
5. Finally, to calculate the cutting volume, the following surfaces are subtracted: cutting (initial ground surface vs. advancing surface) - cutting (design surface vs. advancing surface).
6. With the fill volume, the following surfaces are subtracted: fill (initial land surface vs advance surface) - fill (design surface vs advance surface).

[rsalastopografia]

Hi teerawat.pSCHYQ , Use the steps you described to calculate volume by comparing surfaces. The supervising designer used another method prior to the volume calculation by the surface comparison method.

[rsalastopografia]

Hello friend, the method that is being used for this case is by comparison of surfaces, I have noticed that it is not enough to take one surface and compare it with another; It requires more analysis to perform this calculation and I describe it with images.

[fcernst]

Why do keep saying though.. that you want your surface comparison method to absolutely match volume computed by approximate Sectional methods?

They are not the same. It could be that you or the contractor are being paid by Sectional methods? Apples and oranges when discussing Civil 3D composite surface comparisons and pay quantities computed by Sectional methods. 

[fcernst]

I think you’re Supervisor may be computing volumes for pay quantities by approximate Sectional volume methods at some unknown sampling interval.. and you’re frustrated why you can’t get Civil 3D composite volume surfaces to match up with whatever they are doing with their method and the Supervisor possibly using volume adjustment factors. 

[Joe-Bouza]

The independent cut and fill volumes are calculated in the composite volume calc and the difference is the net cut or fill.

In my opinion by chopping the surface by polygon (AKA by hand) to compare cut and fill separately is a colossal waste of time.
There is an expression in English “Too many cooks spoil the sauce”

if you are getting different cut and fill numbers then the comparison, all that tells me is that the chopped out section have damaged the TIN. 

If the EG vs Advanced has a cut =100 and a Fill=100, and you separate and compare EG vs cut = 75, EG vs fill= 50.  That doesn’t tell me you have a more accurate analysis. It tells me the TIN was mangled by hand and is unreliable.

sorry I disagree with your supervisor .

Make sure your surfaces are clean, compare and accept. 

[rsalastopografia]

I see that the volume obtained by the method used by the supervision is more precise, I noticed the great difference between the volume calculated by the supervision and the volume that I obtained through their suggestions (in this case I am the builder); I lose out as a contractor. Perhaps with a dynamo script you could speed up these surface cuts with cutting polygons and independently for filling. Since I uploaded my case to this forum I expected better suggestions from those mentioned because I previously carried out that process and the values ​​obtained did not work out in my favor; I still appreciate your time for helping in solving the problem statement, greetings.

[rsalastopografia]

Detail the method used by the supervision, also explain through images the volume that was desired to be obtained, greetings.

[Joe-Bouza]

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@rsalastopografia wrote:

I see that the volume obtained by the method used by the supervision is more precise, I noticed the great difference between the volume calculated by the supervision and the volume that I obtained through their suggestions (in this case I am the builder); I lose out as a contractor. Perhaps with a dynamo script you could speed up these surface cuts with cutting polygons and independently for filling. Since I uploaded my case to this forum I expected better suggestions from those mentioned because I previously carried out that process and the values ​​obtained did not work out in my favor; I still appreciate your time for helping in solving the problem statement, greetings.

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Please understand that this forum is a peer to peer users group. we are users like yourself. We share our experience and knowledge freely and willingly. As such users, we struggling our way through the day looking to make things easier for ourselves and others. 

It would be excellent if you can share your supervisors model so we can see the vast differences and possibly understand why.

The polygon you want is the zero contour of the base volume surface

[rsalastopografia]

I am grateful to all the users who responded to my post in search of a solution, on the other hand, when mentioning supervision I am referring to another company of the client that is responsible for verifying and accepting the measurements in the field from the builder; It also applies to volume reconciliation in the office because they have their designer. The method that the supervision used was able to explain to me in their office, but they did not provide me with archive dwg.

[JamesMaeding]

@rsalastopografia 

I read your initial and some other posts, and may not totally get what you want, but it sounds like you have a top, bottom, and intermediate surface going on.

This is exactly what happens with either "progress" volumes, or with modeling "remedial" (overexcavation) which almost every residential and commercial project does.

What you will find is you generally need to composite 2 surfaces, usually to get the "lower" of the two.

In your case, it is the original ground (top), and the middle line you had. You then compare that to the bottom surface to get a volume.

I've seen people do that compositing by hand, but  knowing the cut/fill line between the two. Its a horrible tedious exercise.

You typically must do it twice too on my projects, once for top of OX and once for bottom if 2 different depth criteria for existing and proposed in geotech report.

Having said all that, Civil3d is MISSING the tool to do that.

My tools accomplish it by making a grid sampling of the two surfaces, and the grids get subdivided at edges where a full square cannot be sampled. Maybe other tools out there do true tin to tin sampling, like the civil3d tin volume tool does. It turns out either is accurate enough, and the grid method is much lighter weight so a big advantage.

Anyway, curious if other have used maybe trimble business center, or carlson, smartdraft, or dotsoft tools to do that?

[rsalastopografia]

The case presented is calculation of massive earthwork volume having 3 surfaces (Initial ground surface, Design surface, Advance surface) and obtaining the values ​​of the advance volume within the design by the surface comparison method. I agree with you that civil 3d lacks tools in the mentioned method to be precise in obtaining advance volume with 3 surfaces, its tools are limited to comparing an initial surface and a design. Is the tool you mention by 3D civil cross sections or is it another software?

[fcernst]

Use Subcriteria methods:

 

[rsalastopografia]

Are these subcriteria to be applied by the method of cross sections or comparison of surfaces? I'm not clear

[Joe-Bouza]

Hi @JamesMaeding maybe you can explain to me, ignoring datums because this was not mention or addressed when questioned.

 If there is an EG  and a progress surface (Advanced) how is it the the volume surface  EG vs Progress is not the volume cut or filled from EG  or FG vs progress?

Hypothetically if the job were all cut then the advanced surface would be incremental cut until FG were reached  an vice verse

it seems to me if there is a design cut fill of EG vs FG then as the project advances the progress volume  should eventually add up to the CF of EG vs FG