Volume calculation

[Anonymous]

Hello all,

I am trying to calculate the volume of stockpiles using Civil 3D 2017. I have created 2 surfaces such that a Tin Volume Surface can be produced. I have defined the surfaces with point groups and also given surface boundaries (at the end). When creating a Tin Volume surface it creates a duplicate model below as seen in the attachment given. Why does this happen? I can extract a quantity of material from this but have concerns as to how reliable this is.

Any help on the matter would be great.

Thanks

[neilyj666]

I can't really see what is going on as just able to view on my phone.

I would tackle this by pasting the OGL into a new surface and then removing the TIN points that define the tops of the piles. This assumes a "struck base" i.e. the OGL is linear under the pile. I then just do a simple comparison avoiding creating a Volume Surface unless I need it for something specific.

[Anonymous]

Cheers for getting back to me Neilyj,

I have created two separate surfaces to compare: The 1st being the OGL surface and the 2nd being the fill material, as shown is the pictures below. The only way i know of comparing/computing volumes is through Tin Volume Surface. How do you carry out this comparison method that you are talking about?

OGL Surface BaseFill Material SurfaceDuplicate model created when using Tin Volume Surface. Why has this happened?

[wfberry]

Perhaps if you looked at each surface's STATISTICS and compare minimum and maximum elevations you could see it they are making any sense.

Bilol

[mohammad.banitamim]

Hi”djlgow” actually clear I want to know “do you want to compute volume between 2 surface with a similar coordinates and different heights” Yes? (Just Yes or No)…

[neilyj666]

I can't remember the command as I have added it to my ribbon ... will check tomorrow.

The volume surface method will create an additional surface but the levels will typically in a case like this range from 0 to the max relative height of the piles.

It would be useful if you could share the dwg

[Anonymous]

Yes, I want to compute the volume between two surfaces that i have defined. When doing this a duplicate model of what i what i have produced appears at an elevation of 0. The model i constructed is taken from a Trimble Total Station at height 508m. Does civil 3D for some reason show the Tin Volume Surface at elevation 0? Here is my model, which will help show my issue. 

[Anonymous]

Hi Neilyj,

Here is my model which will help show what my issue is. The model might be fine, i am just not sure if it usual for civil 3d to create a duplicate model at elevation 0. 

Thanks

[Joe-Bouza]

I may be wrong but am I looking at three surfaces: base, comparison and volume

[neilyj666 · Accepted solution]

@Anonymous - The models look perfectly ok to me.

The volume surface below has surface labels which range from around 0 to 3.3ish and represents the relative height of the sand pile above the ogl - this is totally as expected.  The command I couldn't remember is ReportSurfaceVolume as shown in the screen shot

This command gives a volume of 308.5 cu.m. which unsurprisingly is the same as the volume surface but without the overhead of a volume surface.

[M_c3d]

@neilyj666 is correct, the volume surface it has created looks fine to me. Unless you use the reportsurfacevolume tool @neilyj666 suggested, the volume dashboard will always create a tin volume surface

[ChrisRS]

@Anonymous, the duplicate model is the TIN Volume surface.

The "elevation" of each point in the TIN Volume surface is the elevation difference between the Base and Comparison surface at the point. A negative elevation means cut and an positive elevation means fill. Because the cut and fill are relatively small numbers, the surface is near zero. The overlap area of the base and comparison surface determine the boundary of the volume surface.

In this case, your Base and Comparison surfaces have the same boundary, thus the volume surface does as well. The model is all fill and the base surface is somewhat flat. this results in the volume surface looking similar to the comparison surface, but they are not identical. The volume surface is not a duplicate.

If all fill makes sense, what you are doing looks correct. 

[neilyj666]

.....all as explained in other posts in the thread...

[CharlieGreene7827]

Not really sure if this is what is happening when you crease a volume surface you are creating a third surface that will be 0 and will be the difference between the two try and insert points to the surface as surface grid and if the levels are minus and plus figures that is what it is

[CharlieGreene7827]

As a double check you extract the points calculate the mean of the sum of elevation and multiply by the area and that would get you a volume also double check in the surface property’s for the volume and mean also don’t forget to analize