## AutoCAD Civil 3D General Discussion

Member
Posts: 4
Registered: ‎03-20-2011
Message 1 of 15 (3,940 Views)

# Cut and Fill Estimating

3940 Views, 14 Replies
03-20-2011 06:52 AM

I work for construction company as an estimator. Just to be clear, my background is in GIS, Urban Planning and Surveying. I'm quite versed in AutoCAD design and also use it daily for calculating quantity takeoffs for proposed construction projects.

Here's my question. I've been testing Civil 3D as a quick method for calculating cut and fill quantities. I've done some reading and I think I've figured out a simple method of doing this. What I would like to know is if I'm doing this properly.

Below are the steps I've taken to produce my numbers:

1. Existing and proposed elevation marks in the AutoCAD drawing are assigned points with correct z elevations.

note* the existing and proposed elevations cover almost the exact same surface areas. To be clear, if a polyline was connected around the boundary points of each layer, they would almost match up.

2. All points are brought into Civil 3D

3. Existing points are converted into Civil 3D cogo points with the description "existing"

4. Same process as step 3 used for the proposed points with the description "proposed"

5. Existing and proposed cogo points are assigned to separate point groups with relative names

6. Two TIN surfaces are created with surface style "Contours 1m and 5m (design)"

note* I'm not sure what the difference between the (design) and (background) options are

7.  Both existing and proposed point groups are assigned to each relative surface.

8. A TIN volume surface is created using surface style "Contours 1m and 5m (design)" and the "existing" TIN surface is assigned to the base surface, with the "proposed" TIN surface assigned to the comparison surface.

note* Cut and Fill factor are left at 1.000, as I'm unsure how these values effect the TIN volume surface.

Basically that's it. I'm getting some nice cut and fill numbers when I check the properties of the volume surface and they do seem to be accurate, but I would like to be 100% sure that I’m getting accurate information

To reiterate, I am very new to Civil 3D, and any input on my method would be greatly appreciated.

Cheers,

Jeff

p.s. I've attached the file "Cut fill test.dwg" if you would like to see what was done.

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Message 2 of 15 (3,926 Views)

# Re: Cut and Fill Estimating

03-20-2011 07:45 AM in reply to: j3ff1rw1n

If all you have are spot elevations, I would say you are doing it correctly.

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Posts: 103
Registered: ‎09-10-2007
Message 3 of 15 (3,916 Views)

# Re: Cut and Fill Estimating

03-20-2011 08:27 AM in reply to: BrianHailey

Since you've created a comparison surface - 'Cut Fill'.  You can also create color schemes to verify where the cut and fill areas respectively are.

At a glance your drawing looks correct.

Valued Contributor
Posts: 92
Registered: ‎02-01-2007
Message 4 of 15 (3,903 Views)

# Re: Cut and Fill Estimating

03-20-2011 10:32 AM in reply to: j3ff1rw1n

you can also use the surface volume feature under the sufaces pulldown, utilities. I typically just use this feature unless i need to display a color scheme for cut and fill areas. You also have to consider in a compression factor. when they bring in dirt for roads or lot grading they are going to pack it down. In the surface volume feature i typically use a 1.15 fill compaction factor. anyways hopes this helps.

tony carcamo

Senior Design Tech

www.tonyscivil3dworld.blogspot.com

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Registered: ‎08-01-2008
Message 5 of 15 (3,890 Views)

# Re: Cut and Fill Estimating

03-20-2011 12:02 PM in reply to: j3ff1rw1n

Always remebering that the cut and fill factors (also called bulkage factor, swell factors,compaction factor) can vary with material type and compaction method etc so use with caution.

The other thing to consider is that the spot levels accurately define the surface and that breaklines are not required to enhance the triangulation

neilyj
(No connection with Autodesk other than using the products in the real world)

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Registered: ‎03-10-2011
Message 6 of 15 (3,873 Views)

# Re: Cut and Fill Estimating

03-20-2011 01:29 PM in reply to: j3ff1rw1n

Hello Jeff

But just as far as using C3d 2011 i use C3D as a  survey & design  "mostly"  and next a Vols Qc for complex highways

Without a sample of your project I have found that you may be up  the creek.

No 1 civil 3 D is complex with no such thing as a casual user, autocad background more or less of small benefit

Survey robots             1/10 complexity

Gps                             1/10 complexity

C3D                9/10 complexity - it is not a estimating tool i am sad to say unless you use say C3D all day long

But i would say that i Like C3D for it is fare better that LDT (user simple) since  1999 however the complecity has

gone way of the scale

PS  i have my own small survey company

Any comment on your procedures would be difficult at best

PK

Active Member
Posts: 10
Registered: ‎03-10-2011
Message 7 of 15 (3,864 Views)

# Re: Cut and Fill Estimating

03-20-2011 02:21 PM in reply to: j3ff1rw1n

Jeff

i loloked at the DWG and it may be in the long run to farm the work out for like i said C3d is complex and i

would be better to look at a simplier program to hunt down stock pile volumes or excavation volumes.

For a most projects now are made up of assembly of endless drawings and to piece it all together is a chore

for sooner or later you will require design C3D dwgs

Peter K

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Posts: 331
Registered: ‎05-13-2010
Message 8 of 15 (3,853 Views)

# Re: Cut and Fill Estimating

03-20-2011 03:18 PM in reply to: j3ff1rw1n

Your basic premise is right. Create an EG surface from your topo points, and a FG surface for your design points and wither use the volume tool or what you're doing.

The two surfaces do not need to agree in size as the smaller surface will be used.

The same thing can be done in ArcGIS but takes longer and you need to use extensions. C3D is much faster. I do the same as you on a daily basis to estimate volumes. Ignore the suggestion to outsource.

Design and background contour styles are simply different so yo ucan visually tell the difference between youe EG and FG surfaces.

The factors are based on compaction and expansion depending on what you are removing in cut and fil; different materials compact and expand at different rates. For a high level number, leave them at 1.

Eric Collins, P.Tech.(Eng.)

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Intel i7 3770 @ 3.40 GHz
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Civil 3D 2012 SP2
Member
Posts: 4
Registered: ‎03-20-2011
Message 9 of 15 (3,837 Views)

# Re: Cut and Fill Estimating

03-20-2011 04:56 PM in reply to: wdbar

Color schemes are very helpful. It makes it much easier to determine what's being moved based on the borehole data. Thank you.

Member
Posts: 4
Registered: ‎03-20-2011
Message 10 of 15 (3,828 Views)

# Re: Cut and Fill Estimating

03-20-2011 05:34 PM in reply to: j3ff1rw1n

When it comes to farming out this work, it just makes no sense. We have some great Trimble based GPS hardware that we use for site layout, and C3D would complement our surveying hardware as much as our estimating numbers.

As for the rest of the comments, I appreciate all the input. This sounds like the best method to produce the data I’m looking for.

As for bulking and compaction factors, they are always in the back of my head, but I do appreciate the advice.

I also agree ESRI products can produce much of the data I’m looking for, but GIS software (as much as I love it) is somewhat unnecessary for a construction company. On a side note, I have heard good things about Manifold though (cost vs. capability).

Again, thank you all. It is much appreciated.

Jeff

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