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Richard McDonald
2012-08-14, 10:11 AM
I have created a comparison surface to get cut fill volumes.
I have inserted a table to show the different volumes per bands.

On checking through with the Engineer in charge, he asked how the calculation of the volumes for each band is achieved.
Can anybody point me in the direction of any documentation for how Autodesk have set this up?

Many Thanks

mjfarrell
2012-08-14, 12:53 PM
that would depend on how your created your volume surface

if it is a GRID volume that would be average end area

if it is a TIN surface, that would be through a composite method

Also I think for the elevation banding a composite method is used;
however the help file isn't exactly clear on that issue"

Elevations. Used for elevation banding analysis. Renders surface triangles differently according to their elevation range.

Richard McDonald
2012-08-14, 09:07 PM
Thanks Michael.

The image attached may explain things a bit clearer.


The areas and volumes don’t seem to add up. The areas, I think, are cumulative but I am finding it difficult to prove with a rough estimate the volumes of any given band.
Without any way of checking we are just relying on the computers output which could be dangerous.
I need to know how C3D calculates the band volumes so I can double check with a rough calc.

MTIA
Cut Fill.png

Opie
2012-08-15, 02:31 PM
Have you thought about creating an alignment and a series of sample lines? It would at least get you some cross sections to check.

Also, your attached image did not save.

Richard McDonald
2012-08-17, 12:44 PM
I seem to be having trouble uploading the image.
We have just swapped over to Microsoft forefront which has been blocking random net traffic.

I will create a series of offset surfaces mimicking the bands and see what volumes I get from them.
Hopefully it will shed light on how the figures are obtained in the cut fill surface legend table.

Russ's link was helpfull, it looks like the volumes may be determined by the Monte Carlo Integration method which will make manually checking the output impossible.