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]

Hi @rsalastopografia you are welcome.

What to you mean by variations? It has always been my understanding that surface to surface surface comparison is the most accurate. It is pure integration. 

What are you comparing it to, Average end area? You will never get these to match.

It has been my experience if the resulting volumes are not in the range I expect , it can almost certainly be traced to a bust in one or more Tin surface. One errant triangle can change the order of magnitude.

Turn on you triangle, view from different perspectives

I would view these areas as suspiciously inconsistent, compared to the rest of the triangulation.

  I believe these are in the FG : REPERFILADO 4TA ETAPA

[rsalastopografia]

What do you mean by variations? I was referring to the volume results obtained when making the comparisons that you indicated, they are not precise, the results are many hundreds of cubic meters different. I must cube my advance surface only within the FG (4th stage reprofiling), so I make longitudinal profiles projecting the initial terrain, design (FG) and advance surfaces. The advance surface outside the design (FG) is clearly observed in some sections; Therefore, it is required to cube the volume only within the design. I hope you understand my answer, greetings.

[Joe-Bouza]

the triangulation interval are mostly uniform except those area. might throw off results.

what are you comparing to that you can say it is off by a great amount?

https://forums.autodesk.com/t5/civil-3d-forum/how-accurate-are-the-calculated-volumes/td-p/8533260

[rsalastopografia]

A question, with the calculation that you made through your surface comparisons; Did you get the volume I require from my advance? I will upload images below (the volume outlined in blue is required). I hope Google is translating correctly.
1. brown line: initial land surface (EG-TN PAD).
2. magenta line: design surface (FG-REPROFILATING 4TH STAGE).
3. red line: advance surface (Advance Sup).

 the volume outlined in blue is required

 the volume outlined in blue is required

 the volume outlined in blue is required

 the volume outlined in blue is required

[Joe-Bouza]

I looked at it differently.

make another volume surface with 

EG as base and advanced as comparison and you will have that volume 

[rsalastopografia]

When comparing surfaces (EG vs AVANCE) according to your suggestion, the result would not be the volume I require and you can analyze it with the images I uploaded and even with the DWG file. It is a special case that cannot yet be resolved by the surface comparison method. It is not about choosing any surface and comparing it with another, it requires more analysis.

[Joe-Bouza]

Not sure why not. You first picture clearly shows the comparison of EG vs advance.

then each of your subsequent  sketches show the volume between two surfaces.

sorry I’m not full understanding but it looked clear to me

[rsalastopografia]

Requiere mas análisis para resolver mi caso, no es correcto su sugerencia; saludos.

[fcernst]

You don’t say what your section sampling interval is.. the smaller your delta x sampling interval is.. the closer it will approximate your surface composite volume calculation. 

[rsalastopografia]

In my case, the volume calculation by the method of cross sections is not applied. The question is to resolve my case by the surface comparison method by performing a good analysis. The calculated volume should be similar if the method of cross sections were used. ; This is the only way to guarantee that the result of the surface comparison is optimal. The longitudinal profiles were generated to project the surfaces and perform an analysis to obtain the desired volume by the aforementioned method, greetings.

[Joe-Bouza]

I know we have a small language barrier but you have not explained why the volume surfaces are incorrect. Saying they need more analysis is confusing 

Requires more analysis required more explanation.

Volume surface compared two surfaces no more. The accuracy of the surface comparison is completely based on the accuracy of the surfaces.

you can read up on the accuracy of each method. 

I still don’t understand why the comparison shown are not correct. They are the comparison you sketched. Not all but some.

what exactly is the answer you are trying to get? I am very interested 

is my interpretation of “advanced surface” = to earthwork progress in the field?

[rsalastopografia]

To clear up any doubts, calculate the volume by the 2 methods (comparison of surfaces, cross sections), you will notice that your suggestion is quite wrong, it is not about comparing any surface without analyzing what you want to obtain. Explain through images (blue hatching-volume required) what you want to obtain, you can also see in the dwg file; A thorough analysis is required, observing the projections of the surfaces in the longitudinal profiles to finally see how what is requested is achieved (real volume within the design), I hope it is understood.

[Joe-Bouza]

No it is not understood. And I do not think I am alone. We have had several very experienced users try unsuccessfully. I’m afraid we don’t understand your goal.

sorry

[Joe-Bouza]

Apparently this is the wrong way of thinking if it

[teerawat.pSCHYQ]

if you would like to know how obtain volume that need to go, basically yo can do comparison surfaces as following like this.

1. you have the existing ground surface that call "TN-PD" , this surface not need to edit anything

2. you already have design surface that call "REPERFILADO 4TA ETAPA" this is no need to edit

3. then you have progress surface that call "Sub_Avance" this surface also do not edit anyting.

4.  then you make a new surface that maybe call "Existing Ground + Progress surface" 

5. then Edits "Existing Ground + Progress surface" by paste surface "TN-PD" first

6. Then Edits "Existing Ground + Progress surface" again by paste surface by "Sub_Avance", then your "Existing Ground + Progress surface" updated.

7. do Surface Analysis between "Existing Ground + Progress surface" and Design surface "REPERFILADO 4TA ETAPA"  

8. after that you will see current cut and fill, after that you will comparison these value with original value.

these process should be meet your question.

[Joe-Bouza]

I believe this will give good answers. Sounds similar to making three volume surfaces as I earlier described, leaving a simple hand calculation in the end.

very good 

[rsalastopografia]

Hello dear, thank you for taking the time to resolve my case. Please could you be more detailed in the last points, carry out the entire process up to point 6. I attach the image.

[rsalastopografia]

Keep in mind, the volume you want to obtain is shaded in blue with lines (I hope Google translates well), I attach images.

1. brown line: initial terrain surface (EG-TN PAD).
2. magenta line: design surface (FG-reprofiled 4TH STAGE).
3. red line: advance surface (Advance Sup).

 volume shaded in blue (lines) is required

 volume shaded in blue (lines) is required

 volume shaded in blue (lines) is required

 volume shaded in blue (lines) is required

Previously, make the observation by comparing the initial land surface vs. advance surface; However, it was not possible to obtain the volume explained in the images. With that comparison you are going to calculate in a general way and that is not the point; I want to obtain the volume that is within the design (blue shading with lines). I hope your method is more effective and meets what is required, thanks for the contribution (I am using Google Translate).

[Joe-Bouza]

you want the volume comparisson between design and progress. that is the volume surface to make.

I compared EG to Progress 

and EG to FG

if you subtract the two you get FG to progress

All your requirements are achievable, defining the stratum is all that has to be done.

keep in mind, when you create a stratum there is no calculation where one surface is and another surface is not

[rsalastopografia]

Good evening, I appreciate your help in trying to solve my case. I carried out the procedure with your suggestions, however when reconciling volume measurement with supervision I came across a huge difference. I think the C3D surface comparison tool still needs to be improved to achieve a good calculation. I attach images.

 supervision volume measurement.

 calculated volume

I would appreciate if someone from the forum shares any C3D technique related to surface comparison to perform a good calculation, greetings.