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Surface Manipulation

62 REPLIES 62
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Message 1 of 63
tysonbird
2297 Views, 62 Replies

Surface Manipulation

I am curious if it is possible to modify only specific portions of a surface? For example, I have recieved an xml surface representing FG for a project, and want to do an earthwork calculation, could I raise and lower only portions of the project say by using specific boundaries for the asphalt paving, concrete etc. and then implement the raise & lower surface feature for these portions of the FG surface.

 

At this time I have been creating multiple surfaces for each particular feature of the site, then paste the FG surface, add a boudary and lower appropriately. Finally, I have to go through and paste each particular feature and its small surface into one "subgrade surface" to get an accurate representation. This method results in countless small surfaces and alot of leg work for something that seems like it should be simple.

 

I know that the surface defentions (FL's or corridors), should they be provided, would make this easy, but there have been several occasions where these are not being made availble by the project sponsor. 

 

 

62 REPLIES 62
Message 2 of 63
Joe-Bouza
in reply to: tysonbird

Not that I know of but the items you refer would be an easy area time depth, no?

Thank you

Joseph D. Bouza, P.E. (one of 'THOSE' People)

HP Z210 Workstation
Intel Xeon CPU E31240 @ 3.30 Hz
12 GB Ram


Note: Its all Resistentialism, so keep calm and carry on

64 Bit Win10 OS
Message 3 of 63
CADvisers
in reply to: tysonbird

It sounds like the method your describing is close, but I would suggest pasting the whole FG into a new SUBGRADE surface AND THEN lower to your subgrade depth and apply your boundaries.

 

If you need the SUBGRADE surface with the original FG to compare to EG, then you'll have to create one more surface (FG & SUBGRADE) and paste the original FG and then the SUBGRADE.

 

Don't try to paste the SUBGRADE back into the FG, that creates a circular reference.

 

Jonathan Stewart
CADvisers
P.O. Box 7811
Lancaster, PA 17604
Ph. 717-468-3111


Message 4 of 63
Neilw_05
in reply to: tysonbird

I think the technique you are using is the most accurate aside from recreating the model with corridors and gradings.

 

I can't think of any other techniques that don't require a similar amount of work. C3D's lack of subgrade tools for gradings is one of the reasons I have preferred a competing product up to now.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 5 of 63
Neilw_05
in reply to: Joe-Bouza

Joe,

 

The problem with area times depth is you have to account for whether the subgrade is in cut or fill. If in cut you'll need to add the subgrade depth to the depth from FG, in fill you'll need to subtract the subgrade depth.Typically the FG is going to have both conditions.

 

You can create an ISOPACH surface to establish which parts are in cut or fill and then use the appropriate Area x Depth for each region but that can end up being alot of work when you have varying subgrade depths (i.e. under pavement vs. under sidewalks, etc) as well as when the subgrade transitions between cut and fill in numerous places within a feature. Too it is not as accurate since the cut/fill depth becomes variable near the edges where the subgrade transitions from cut to fill.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 6 of 63
tysonbird
in reply to: tysonbird

You are correct nielw. Most sites involve both cuts and fills therefore area x depth is not helpful. Sounds like my procedure is easiest way to go about it without rebuilding FL's and corridors.

Unfortunate, as this should be relatively easy. Contractor software does this on a regular basis with little problems.

Message 7 of 63
CADvisers
in reply to: tysonbird

I'm not seeing the difficulty in the process I mention above.

 

I do this on a regular basis.  I always have subgrade surfaces that have the FG pasted in and boundaries around my various paving, conc. etc. and then lowered to my depth of material. 

 

Note:

You don't need multiple surfaces for non-contigous areas.  You can control individual areas by having an overall hide boundary followed by multiple show boundaries.

 

This way it is always dymanic and continually current with any changes that are made to the FG.

 

In addition, these additional sub-grade surfaces can be shown on profile views with the profile hatches and all be up to date and current with any FG changes.

 

 

Jonathan Stewart
CADvisers
P.O. Box 7811
Lancaster, PA 17604
Ph. 717-468-3111


Message 8 of 63
neilyj666
in reply to: CADvisers

I use this method to tackle this problem - works well for me...

 

http://ericchappell.blogspot.co.uk/2012/01/magical-way-to-calculate-volumes.html

 

.....but raises another question: how can Civil 3D be called a BIM tool when it can't do calcualtions such as this easily. Obviously corridors can extract quantities fairly painlessly but not everything needs, or works well with, a corridor

neilyj (No connection with Autodesk other than using the products in the real world)
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Message 9 of 63
Joe-Bouza
in reply to: Neilw_05

Hi Neil

 

A picture is worth a thousand words. If total earth work is done between FG an EG any proposed volume pavement, sidewalks curbs drainage structures will always increas the total cut on a job. Show me how this math dos not work?

 

cutfill2.png

 

 

 

 

Thank you

Joseph D. Bouza, P.E. (one of 'THOSE' People)

HP Z210 Workstation
Intel Xeon CPU E31240 @ 3.30 Hz
12 GB Ram


Note: Its all Resistentialism, so keep calm and carry on

64 Bit Win10 OS
Message 10 of 63
Joe-Bouza
in reply to: tysonbird

See my response to Neil. Be free to show me the error in the math

Thank you

Joseph D. Bouza, P.E. (one of 'THOSE' People)

HP Z210 Workstation
Intel Xeon CPU E31240 @ 3.30 Hz
12 GB Ram


Note: Its all Resistentialism, so keep calm and carry on

64 Bit Win10 OS
Message 11 of 63
troma
in reply to: Joe-Bouza

Joe, I think it depends what information you're looking for.  If all you need to know is the total earth balance (does this area have too much earth, or not enough, and by how much?) then I think you're right.  But if the contractor is going to quote one price for cutting earth and remove from site, a different price for cut to fill on site, and another price for placing imported fill you're in a whole other kettle of fish.  You can't just say "we need this much fill imported/exported". You need to know exactly how much you are cutting to form the subgrade, and how much you are filling.


Mark Green

Working on Civil 3D in Canada

Message 12 of 63
troma
in reply to: tysonbird

In answer to the original question, I don't think there's a lot of time to be saved from what you are doing.  I build surfaces from scratch and do it the same way!  My one question would be: why do you paste all the subgrade together?  I leave them all seperate (but on the same style as each other).  That way I can report the volumes per area, and we get a good idea of where the site is in cut and where in fill, which may lead to staging decisions.


Mark Green

Working on Civil 3D in Canada

Message 13 of 63
Joe-Bouza
in reply to: troma

Agreed - in part.

 

Our contract documents have a line item for select fill and a line item for excavation it does not specify exactly how much cut or fill at point A or B. They buy the job on totals. They have the grading plans to determine a bid price and I don't think his line item bid will vary that much due to location.

 

Granted if this were 10 miles of highway I agree it may be a whole other kettle of fish, but does it really make that much difference over the whole job? The diagram is the same between station 10+00 and 10+50 and so on

Thank you

Joseph D. Bouza, P.E. (one of 'THOSE' People)

HP Z210 Workstation
Intel Xeon CPU E31240 @ 3.30 Hz
12 GB Ram


Note: Its all Resistentialism, so keep calm and carry on

64 Bit Win10 OS
Message 14 of 63
Joe-Bouza
in reply to: troma


@troma wrote:

In answer to the original question, I don't think there's a lot of time to be saved from what you are doing.  I build surfaces from scratch and do it the same way!  My one question would be: why do you paste all the subgrade together?  I leave them all seperate (but on the same style as each other).  That way I can report the volumes per area, and we get a good idea of where the site is in cut and where in fill, which may lead to staging decisions.



To paraphrase David Letterman... You have crystalized my thoughts eloquently. Smiley Wink

Thank you

Joseph D. Bouza, P.E. (one of 'THOSE' People)

HP Z210 Workstation
Intel Xeon CPU E31240 @ 3.30 Hz
12 GB Ram


Note: Its all Resistentialism, so keep calm and carry on

64 Bit Win10 OS
Message 15 of 63
neilyj666
in reply to: Joe-Bouza

We recently had a consultant proudly announce that the job we were tendering for had a cut and fill balance until we got the CAD drawings and found that there was indeed a balance from EGL to FGL but it was a different story when topsoil had been removed and the FGL adjusted for construction thicknesses..!!!

 

It is not always useful knowing the overall cut/fill but where it all is as the cut may be at one end of the job and the fill at the other which will greatly affect the earthworks costs

neilyj (No connection with Autodesk other than using the products in the real world)
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Win 11 Pro x64, 1Tb Primary SSD, 1Tb Secondary SSD
64Gb RAM Intel(R) Xeon(R) W-11855M CPU @ 3.2GHz
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Message 16 of 63
Jay_B
in reply to: Joe-Bouza

Nice sketch Joe.

 

The way I see it if you look at the dashed blue EG line & do a volume calc between the EG surface & the Datum surface

(bottom most red line in sketch) you have your raw cut / fill #'s. (splitting hairs a bit but you may also have a thickness representing topsoil etc. on the tie slopes shown which would alter the datum line a bit).

Then you have your proposed quantites that will not be included as cut / fill but also must be accounted for & calculated in your quantities.

 

Jay

C3D 2018.1
C3D 2016 SP4

Win 7 Professional 64 Bit
Message 17 of 63
Joe-Bouza
in reply to: Jay_B

Thanks Jay

 

My renderings were always the envy of the class (LOL)

 

Here is a revised sketch. Area of Top soil increases the total cut

 

 

 

Thank you

Joseph D. Bouza, P.E. (one of 'THOSE' People)

HP Z210 Workstation
Intel Xeon CPU E31240 @ 3.30 Hz
12 GB Ram


Note: Its all Resistentialism, so keep calm and carry on

64 Bit Win10 OS
Message 18 of 63
troma
in reply to: Joe-Bouza


@Joe-Bouza wrote:

Agreed - in part.

 

Our contract documents have a line item for select fill and a line item for excavation it does not specify exactly how much cut or fill at point A or B. They buy the job on totals. They have the grading plans to determine a bid price and I don't think his line item bid will vary that much due to location.

 

Granted if this were 10 miles of highway I agree it may be a whole other kettle of fish, but does it really make that much difference over the whole job? The diagram is the same between station 10+00 and 10+50 and so on


I'm not talking about location Joe, I'm talking about totals.  Your diagram says that the area x depth is always a reduction in Fill, or conversly an increase in Cut.  But which is it?  I could have a site that works out to a balance, but I need to know if it is a reduction in cut (reduction in price) or an increase in fill (increase in price).

It could be cut 1000000 cubic metres and fill 1000000 cubic metres, or it could be cut 100 cubic metres and fill 100 cubic metres.  Your method doesn't let us know which.


Mark Green

Working on Civil 3D in Canada

Message 19 of 63
Jay_B
in reply to: troma

Many good points in this thread & it seemed to start out in a general sense and became more advanced with each post adding multiple assumptions.

 

Generically speaking I think most of us can aggree on how to arrive at the overall cut/fill raw volumes. (Assuming the site is all wonderful sand to begin with.)

 

Then we could start talking Soil constructability issues (rock exc., mucking etc.), whether the site will balance.

Those are all valid points we must deal with which will change our approach & volume numbers greatly.

Without a lot more specifics re: the original post project scenario it get's quite speculative IMHO.

 

Jay

C3D 2018.1
C3D 2016 SP4

Win 7 Professional 64 Bit
Message 20 of 63
Joe-Bouza
in reply to: troma

My diagram shows that anything in the proposed section below FG increase the total cut.

 

 

 

EG -vs-FG surface analysis:

 

Cut:                                                        100 cubic meters

Fill:                                                         200 cubic meters

Unadjusted net                                100 cubic meters (F)

 

Area depth Adjustments for pavement, topsoil, structures etc.: 300 cubic meters

 

Total adjusted earthwork:           200 cubic meters (C)

 

I enjoy the debate but no one has mathematically proved this wrong yet Smiley Wink show me the numbers Smiley Wink

Thank you

Joseph D. Bouza, P.E. (one of 'THOSE' People)

HP Z210 Workstation
Intel Xeon CPU E31240 @ 3.30 Hz
12 GB Ram


Note: Its all Resistentialism, so keep calm and carry on

64 Bit Win10 OS

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