AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

Reply
*Antoljak, Strahimir
Message 1 of 14 (187 Views)

RockSurf

187 Views, 13 Replies
10-09-2003 11:24 PM
We are multidiscipline company
Civil/Geotech/Environmental/etc
and here is the fairly frequent
requirement we have with
regard to Rock Surface/Contours
(but I can envision very similar
application/benefit for creating
pollutions surface/contours or
anything else).

We get existing surface data
from surveyors. This is always
detailed.

Then our Geotech/Environmental
people go to the site and collect
boring/environmental logs. The
number of logs may very between
say 30 (more often) to 150 or more.

In certain cases the geotech people
look to encounter rock and they
collect rock depths/elevations.
(The environmental people collect
PID values, etc).

So we have very detailed existing
surface and only 30+ points to represent
rock depth. Often, the geotech people
want to see estimated/rough rock surface
and contours. Now, 30+ points is too
few points, I'd say, even for approximate
surface.

Is there a way, or can it be built in the
future release of Civil3D, to automatically
(not manually) generate multiple interpolated
points based on 30+ known points and
accounting for existing surface - see attached
figure.

Thanks,

--
Strah @ Langan
*Cannon, Steve
Message 2 of 14 (187 Views)

Re: RockSurf

10-10-2003 12:23 AM in reply to: *Antoljak, Strahimir
Hi,

Disclaimer: I know NOTHING about Civil3d, I am just here lurking, learning
what I can about the product.

However, with LDD you may be able to achieve your goal:

1) Make a terrain surface representing the Top of Ground elevations (a point
in the terrain may be at MSL, e.g. 5280)

2) Make an LDD terrain surface representing Bore hole depths (a point would
be a positive depth, e.g., +10).

3) Run a composite volume with a stratum for MSL vs. DEPTH, and LDD creates
a composite surface. This composite surface represents the difference
between the two compared surfaces ( a point in the terrain is the
difference, e.g. 5280 - 10 = 5270).

4) Convert the composite surface to a terrain surface and you have your
guesstimated top of rock surface.


I wish to make two additional points:

1) Playing with the triangulation (flipping faces) of the borehole tin may
give you drastically different rock surfaces (based on limited coverage of
wide-spaced boreholes). Perhaps this process is easier and more interactive
in Civil3d, allowing you to play with alternatives.

2) With my experience with geology in New Mexico, I would never adopt your
hypothesis that the profile of the top of bedrock is in any way congruously
related to the top of topsoil profile. But your experience with geology in
your location may support your hypothesis.

Can this be done easier or differently in CIVIL3D? Maybe others will
contribute...

sc

Strahimir Antoljak wrote in message
news:FE2978F1CF422943E2C1CB9F55D5994F@in.WebX.maYIadrTaRb...
>
> We are multidiscipline company
> Civil/Geotech/Environmental/etc
> and here is the fairly frequent
> requirement we have with
> regard to Rock Surface/Contours
> (but I can envision very similar
> application/benefit for creating
> pollutions surface/contours or
> anything else).
>
> We get existing surface data
> from surveyors. This is always
> detailed.
>
> Then our Geotech/Environmental
> people go to the site and collect
> boring/environmental logs. The
> number of logs may very between
> say 30 (more often) to 150 or more.
>
> In certain cases the geotech people
> look to encounter rock and they
> collect rock depths/elevations.
> (The environmental people collect
> PID values, etc).
>
> So we have very detailed existing
> surface and only 30+ points to represent
> rock depth. Often, the geotech people
> want to see estimated/rough rock surface
> and contours. Now, 30+ points is too
> few points, I'd say, even for approximate
> surface.
>
> Is there a way, or can it be built in the
> future release of Civil3D, to automatically
> (not manually) generate multiple interpolated
> points based on 30+ known points and
> accounting for existing surface - see attached
> figure.
>
> Thanks,
>
> --
> Strah @ Langan
*Antoljak, Strahimir
Message 3 of 14 (187 Views)

Re:

10-10-2003 01:30 AM in reply to: *Antoljak, Strahimir
Hi,

> 2) With my experience with geology in New Mexico, I would never adopt your
> hypothesis that the profile of the top of bedrock is in any way
congruously
> related to the top of topsoil profile. But your experience with geology
in
> your location may support your hypothesis.

well I definitely agree this is a tough issue to digest, and I am
sure this will be open discussion forever. I exaggerated
my sketch only for the purpose of making point of what
I would like to see available, or know how to accomplish.

I do not claim this is necessarily true. I heard geotechnical
engineers claim geotechnical engineering is more art than
engineering. Why? Because the investigations are done
point wise and then from what was found in discrete points,
educated guesses (or sometimes they may be less educated)
are done for the entire 'halfspace' - surrounding area.
(pretty bold guess I'd say).

Everybody ever been in touch with geotechnical engineering
is aware of that fact. That's why 'art' and that's why enormous
factors of safety as compared to some other civil engineering
disciplines (say structural engineering) - you really do not know
exactly what is going on under the surface.

Just as a comparison I will take Finite Element Analysis
(FEM). When something is modeled as finite element
model, everyone doing it is aware that the smaller the
finite elements are, the greater chances are to get more
accurate analysis results. But then it is costly (time consuming)
Or, you may have large elements and quick analysis.
In geotech engineering there are codes, and they may
require min 1 borehole per 5000 ft2 to 1 boring / 25000 ft2
or there may be some other constraints to require
more borings for the same area. But then it is
costly (money and time consuming) but of course more
accurate.

To conclude, this surface approximation is done anyway
(manually) either because project manager wants to include
that in their report or a client asks for that. To emphasize again,
everybody knows that what is among points is (an educated)
guess, and there is a big note accompanying such drawing
saying "THIS IS ONLY ESTIMATED ROCK SURFACE..."
or something of that kind.

What I am asking for is to have ability to do it quickly
and easily, maybe several versions of such 'educated guesses'
if possible and then let us users, based upon our accumulated
geotechnical/geological engineering experience decide how
accurate that is, and how to present it to a client.
There are such software on the market anyhow,
but I would like to see that option in Civil3D and use
one software rather than buy another too, and in my opinion,
with underlying Civil3D engine, it may not be even that difficult.

Thanks for you input,

--
Strah @ Langan

"Steve Cannon" wrote in message
news:6E3E8148D66BD2CCAD08374DF87A54D8@in.WebX.maYIadrTaRb...
> Hi,
>
> Disclaimer: I know NOTHING about Civil3d, I am just here lurking, learning
> what I can about the product.
>
> However, with LDD you may be able to achieve your goal:
>
> 1) Make a terrain surface representing the Top of Ground elevations (a
point
> in the terrain may be at MSL, e.g. 5280)
>
> 2) Make an LDD terrain surface representing Bore hole depths (a point
would
> be a positive depth, e.g., +10).
>
> 3) Run a composite volume with a stratum for MSL vs. DEPTH, and LDD
creates
> a composite surface. This composite surface represents the difference
> between the two compared surfaces ( a point in the terrain is the
> difference, e.g. 5280 - 10 = 5270).
>
> 4) Convert the composite surface to a terrain surface and you have your
> guesstimated top of rock surface.
>
>
> I wish to make two additional points:
>
> 1) Playing with the triangulation (flipping faces) of the borehole tin may
> give you drastically different rock surfaces (based on limited coverage of
> wide-spaced boreholes). Perhaps this process is easier and more
interactive
> in Civil3d, allowing you to play with alternatives.
>
> 2) With my experience with geology in New Mexico, I would never adopt your
> hypothesis that the profile of the top of bedrock is in any way
congruously
> related to the top of topsoil profile. But your experience with geology
in
> your location may support your hypothesis.
>
> Can this be done easier or differently in CIVIL3D? Maybe others will
> contribute...
>
> sc
>
> Strahimir Antoljak wrote in message
> news:FE2978F1CF422943E2C1CB9F55D5994F@in.WebX.maYIadrTaRb...
> >
> > We are multidiscipline company
> > Civil/Geotech/Environmental/etc
> > and here is the fairly frequent
> > requirement we have with
> > regard to Rock Surface/Contours
> > (but I can envision very similar
> > application/benefit for creating
> > pollutions surface/contours or
> > anything else).
> >
> > We get existing surface data
> > from surveyors. This is always
> > detailed.
> >
> > Then our Geotech/Environmental
> > people go to the site and collect
> > boring/environmental logs. The
> > number of logs may very between
> > say 30 (more often) to 150 or more.
> >
> > In certain cases the geotech people
> > look to encounter rock and they
> > collect rock depths/elevations.
> > (The environmental people collect
> > PID values, etc).
> >
> > So we have very detailed existing
> > surface and only 30+ points to represent
> > rock depth. Often, the geotech people
> > want to see estimated/rough rock surface
> > and contours. Now, 30+ points is too
> > few points, I'd say, even for approximate
> > surface.
> >
> > Is there a way, or can it be built in the
> > future release of Civil3D, to automatically
> > (not manually) generate multiple interpolated
> > points based on 30+ known points and
> > accounting for existing surface - see attached
> > figure.
> >
> > Thanks,
> >
> > --
> > Strah @ Langan
>
>
>
>
*Jessup, Allen S.
Message 4 of 14 (187 Views)

Re:

10-10-2003 01:50 AM in reply to: *Antoljak, Strahimir
You point out one of the disadvantages of using a product that is targeted
at a wide user base. You don't find many tools that are written specifically
for one industry. While you will find software written with the geotechnical
field specifically in mind will do what you are looking for. The software
written for the Civil in general will not. What you might hope for is that
if there is enough market for it some one might write an add on for this.

I don't know anything about the geotechnical area. Does anyone use Ground
Penetrating Radar to get a better idea of the rock surface? I've seen GPR
used in Archeology.

Allen

"Strahimir Antoljak" wrote in message
news:BB4AD9D7968B2770411AC12B30170B41@in.WebX.maYIadrTaRb...

> To conclude, this surface approximation is done anyway
> (manually) either because project manager wants to include
> that in their report or a client asks for that. To emphasize again,
> everybody knows that what is among points is (an educated)
> guess, and there is a big note accompanying such drawing
> saying "THIS IS ONLY ESTIMATED ROCK SURFACE..."
> or something of that kind.
>
> What I am asking for is to have ability to do it quickly
> and easily, maybe several versions of such 'educated guesses'
> if possible and then let us users, based upon our accumulated
> geological engineering experience decide how
> accurate that is, and how to present it to a client.
> There are such software on the market anyhow,
> but I would like to see that option in Civil3D and use
> one software rather than buy another too, and in my opinion,
> with underlying Civil3D engine, it may not be even that difficult.
>
> Thanks for you input,
>
> --
> Strah @ Langan
*Cannon, Steve
Message 5 of 14 (187 Views)

Re:

10-10-2003 02:04 AM in reply to: *Antoljak, Strahimir
> What you might hope for is that if there is
> enough market for it some one might
> write an add on for this.

I apologize for being a little off topic, but does C3D include a VBA or LISP
API for new Land objects?

sc
*Antoljak, Strahimir
Message 6 of 14 (187 Views)

Re:

10-10-2003 02:24 AM in reply to: *Antoljak, Strahimir
Well, I am surprised with that
much of attention for that matter.

I am just a person who does
not recognize discipline boundaries
that strictly these days. Many today's
projects are interdisciplinary and complex,
tend to show as many data in a single
project as possible, interacting among
different disciplines - site, architectural,
structural, mechanical, electrical, etc.

In our company this rock surfacing/contouring
is done with LDT, by a site/civil engineer,
manually estimating points 'in between'
and creating rock surface and contours.

Funny enough, I've also just gotten
an off newsgroup email alerting me
that capability I was asking
for, exists in another Site/Civil software.
So my thought is why not Civil3D as
well.

Thanks,
--
Strah @ Langan



"Allen S. Jessup" wrote in message
news:0BD3F6BF7F71B7F12BD8D048FED6F108@in.WebX.maYIadrTaRb...
> You point out one of the disadvantages of using a product that is targeted
> at a wide user base. You don't find many tools that are written
specifically
> for one industry. While you will find software written with the
geotechnical
> field specifically in mind will do what you are looking for. The software
> written for the Civil in general will not. What you might hope for is that
> if there is enough market for it some one might write an add on for this.
>
> I don't know anything about the geotechnical area. Does anyone use Ground
> Penetrating Radar to get a better idea of the rock surface? I've seen GPR
> used in Archeology.
>
> Allen
>
> "Strahimir Antoljak" wrote in message
> news:BB4AD9D7968B2770411AC12B30170B41@in.WebX.maYIadrTaRb...
>
> > To conclude, this surface approximation is done anyway
> > (manually) either because project manager wants to include
> > that in their report or a client asks for that. To emphasize again,
> > everybody knows that what is among points is (an educated)
> > guess, and there is a big note accompanying such drawing
> > saying "THIS IS ONLY ESTIMATED ROCK SURFACE..."
> > or something of that kind.
> >
> > What I am asking for is to have ability to do it quickly
> > and easily, maybe several versions of such 'educated guesses'
> > if possible and then let us users, based upon our accumulated
> > geological engineering experience decide how
> > accurate that is, and how to present it to a client.
> > There are such software on the market anyhow,
> > but I would like to see that option in Civil3D and use
> > one software rather than buy another too, and in my opinion,
> > with underlying Civil3D engine, it may not be even that difficult.
> >
> > Thanks for you input,
> >
> > --
> > Strah @ Langan
>
>
>
*Putnam, Chris
Message 7 of 14 (187 Views)

Re:

10-10-2003 02:54 AM in reply to: *Antoljak, Strahimir
The technique described by Steve should work equally well in Civil 3D.
Volume surfaces are the mechanism for "subtracting" two surfaces from each
other, so if you can construct a surface that represents "approximate offset
distance" you can subtract it from the existing ground surface to obtain the
result.

In Civil 3D the steps would be ( with credit to Steve for the steps that
I copied! )

1) Make a terrain surface representing the Top of Ground elevations (a point
in the terrain may be at MSL, e.g. 5280)

2) Make a terrain surface representing Bore hole depths (a point would be a
positive depth, e.g., +10).

2a) (Optional) use one of the smoothing methods to add interpolated points
to the bore hole surface ( this should help minimize the triangulation
problems that Steve mentioned ) Kriging would probably work best for this
because it does not depend on the existing triangulation, only on the point
coordinates and elevations. Choice of smoothing parameters could have a
significant impact on the results. Natural neighbor should give good
results if you're already satisfied with the triangulation and don't need to
add points beyond the extents of your borehole data. You could also
manually augment the borehole surface with aproximate points/edge editing
based on engineering knowledge of the local geology.

3) Create a Volume or Grid Volume surface using the top of ground surface as
the "Comparison Surface" and the bore hole surface as the "Base surface"

I'm pretty sure that there have been other requests for functionality
similar to your original request, but I'll pass your request on to the
surface team. If you have a specific interpolation method in mind that
isn't covered by the smoothing options, we'd like to hear about that as
well.

Chris Putnam
Software Engineer
Autodesk Civil 3D Team
*Jessup, Allen S.
Message 8 of 14 (187 Views)

Re:

10-10-2003 03:17 AM in reply to: *Antoljak, Strahimir
No reason why not other than it wasn't included in the menus. The underlying
software is certainly capable of it. Steve C.'s question about VBA & Lisp
addresses this. If these are available in C3D then it should be possible to
write a program that does thin inside the product. This problem should be
similar to offsetting a surface .

Allen

"Strahimir Antoljak" wrote in message
news:smileyvery-happy:400E84F38426434A04F4B749ECFE24E@in.WebX.maYIadrTaRb...
> Funny enough, I've also just gotten
> an off newsgroup email alerting me
> that capability I was asking
> for, exists in another Site/Civil software.
> So my thought is why not Civil3D as
> well.
>
> Thanks,
> --
> Strah @ Langan
>
>
>
> "Allen S. Jessup" wrote in message
> news:0BD3F6BF7F71B7F12BD8D048FED6F108@in.WebX.maYIadrTaRb...
> > You point out one of the disadvantages of using a product that is
targeted
> > at a wide user base. You don't find many tools that are written
> specifically
> > for one industry. While you will find software written with the
> geotechnical
> > field specifically in mind will do what you are looking for. The
software
> > written for the Civil in general will not. What you might hope for is
that
> > if there is enough market for it some one might write an add on for
this.
> >
> > I don't know anything about the geotechnical area. Does anyone use
Ground
> > Penetrating Radar to get a better idea of the rock surface? I've seen
GPR
> > used in Archeology.
> >
> > Allen
> >
> > "Strahimir Antoljak" wrote in message
> > news:BB4AD9D7968B2770411AC12B30170B41@in.WebX.maYIadrTaRb...
> >
> > > To conclude, this surface approximation is done anyway
> > > (manually) either because project manager wants to include
> > > that in their report or a client asks for that. To emphasize again,
> > > everybody knows that what is among points is (an educated)
> > > guess, and there is a big note accompanying such drawing
> > > saying "THIS IS ONLY ESTIMATED ROCK SURFACE..."
> > > or something of that kind.
> > >
> > > What I am asking for is to have ability to do it quickly
> > > and easily, maybe several versions of such 'educated guesses'
> > > if possible and then let us users, based upon our accumulated
> > > geological engineering experience decide how
> > > accurate that is, and how to present it to a client.
> > > There are such software on the market anyhow,
> > > but I would like to see that option in Civil3D and use
> > > one software rather than buy another too, and in my opinion,
> > > with underlying Civil3D engine, it may not be even that difficult.
> > >
> > > Thanks for you input,
> > >
> > > --
> > > Strah @ Langan
> >
> >
> >
>
>
*Putnam, Chris
Message 9 of 14 (187 Views)

Re:

10-10-2003 05:29 AM in reply to: *Antoljak, Strahimir
Yes, there's a VBA API. Look in the samples directory under "Civil 3D
ActiveX" (or something like that) for some sample projects to get you
started.

Chris Putnam
Software Engineer
Autodesk Civil 3D Team
*Boys, Doug
Message 10 of 14 (187 Views)

Re:

10-10-2003 05:39 AM in reply to: *Antoljak, Strahimir
Steve's approach will create a surface but Strahimir pointed out that there
may be only a few isolated borehole depths to rock. Interpolating between
these will not "follow" the surface very well.

But "guessing" some extra in-between points on the rock surface may be much
easier using Steve's method. You would only have to choose a "depth" to rock
at each new point which may be easier to do by inspection of the depths to
rock in the known boreholes surrounding the new point.

(PS What Steve, you haven't even been given a copy of Civil 3D ? Who *** have they got beta testing then ?)

Doug Boys Cardno MBK Brisbane Australia
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