Creating a surface from AEC contours??

[Anonymous]

I'm having one heck of a time with this one...

I work for an engineering firm. We get the survey information from one of
three places: The surveyor, the landscape architect or, God forbid, the
Architect (depending on where we are in the chain of command of any given
project). When we get the survey, 99.9% of the time we only get a DWG with
maybe AEC contours but mostly PLINES with a Z elevation. Getting the point
files or a DTM is next to impossible.

So, given everything that I've read to date regarding the no-no's of
creating a surface from contours only (point groups are better), what's the
BEST way to get a surface that represents the contours in the drawing?? My
first few attempts resulted in the contours crossing boundary lines and I
even had a few contours that crossed other contours!

Any input that anyone can give will be greatly appreciated.

Thanks in advance!


Matt W
"What am I gonna do with 40 subscriptions to Vibe?"

[Anonymous]

Hi,

Try harder to get the original surface. If you have AEC contours, then you
know someone has an electonic surface model.

The time you spend on administrative effort in doing this will reduce over
time as your clients come to realise your needs. Also you cannot guarantee
your work without the model.

Also you do not need to spend any engineering time trying to make a
reasonable model from the contours.
--

Laurie Comerford
CADApps
www.cadapps.com.au
"Matt W" wrote in message
news:5049176@discussion.autodesk.com...
I'm having one heck of a time with this one...

I work for an engineering firm. We get the survey information from one of
three places: The surveyor, the landscape architect or, God forbid, the
Architect (depending on where we are in the chain of command of any given
project). When we get the survey, 99.9% of the time we only get a DWG with
maybe AEC contours but mostly PLINES with a Z elevation. Getting the point
files or a DTM is next to impossible.

So, given everything that I've read to date regarding the no-no's of
creating a surface from contours only (point groups are better), what's the
BEST way to get a surface that represents the contours in the drawing?? My
first few attempts resulted in the contours crossing boundary lines and I
even had a few contours that crossed other contours!

Any input that anyone can give will be greatly appreciated.

Thanks in advance!


Matt W
"What am I gonna do with 40 subscriptions to Vibe?"

[Anonymous]

Thanks Laurie!

So what would be the BEST thing to obtain? The DTM folder from LDT?? A DWG
with the TIN?? The point groups (if any) that were used to create the
surface??

I don't think any of the surveyors or landscape architects that we deal with
have C3D. If they do, they're not using it. Most of the
engineers/architects/surveyors are still running 2000.

--
Matt W
"What am I gonna do with 40 subscriptions to Vibe?"


"Laurie Comerford" wrote in message
news:5049342@discussion.autodesk.com...
Hi,

Try harder to get the original surface. If you have AEC contours, then you
know someone has an electonic surface model.

The time you spend on administrative effort in doing this will reduce over
time as your clients come to realise your needs. Also you cannot guarantee
your work without the model.

Also you do not need to spend any engineering time trying to make a
reasonable model from the contours.
--

Laurie Comerford
CADApps
www.cadapps.com.au
"Matt W" wrote in message
news:5049176@discussion.autodesk.com...
I'm having one heck of a time with this one...

I work for an engineering firm. We get the survey information from one of
three places: The surveyor, the landscape architect or, God forbid, the
Architect (depending on where we are in the chain of command of any given
project). When we get the survey, 99.9% of the time we only get a DWG with
maybe AEC contours but mostly PLINES with a Z elevation. Getting the point
files or a DTM is next to impossible.

So, given everything that I've read to date regarding the no-no's of
creating a surface from contours only (point groups are better), what's the
BEST way to get a surface that represents the contours in the drawing?? My
first few attempts resulted in the contours crossing boundary lines and I
even had a few contours that crossed other contours!

Any input that anyone can give will be greatly appreciated.

Thanks in advance!


Matt W
"What am I gonna do with 40 subscriptions to Vibe?"

[Anonymous]

If you're getting contours crossing contours, I think you most likely have
some bad elevations, etc., in the objects.

For most projects, creating a surface from contours should be 'good enough'
to get the job done, just make a 'no display' style and use the contours you
received for display/plotting. It's far less than ideal of course, and as
Laurie suggested, it would be *best* to get the DTM or at least the DTM data
(breaklines and points) used to create the original surface.

"Matt W" wrote in message
news:5049176@discussion.autodesk.com...
I'm having one heck of a time with this one...

I work for an engineering firm. We get the survey information from one of
three places: The surveyor, the landscape architect or, God forbid, the
Architect (depending on where we are in the chain of command of any given
project). When we get the survey, 99.9% of the time we only get a DWG with
maybe AEC contours but mostly PLINES with a Z elevation. Getting the point
files or a DTM is next to impossible.

So, given everything that I've read to date regarding the no-no's of
creating a surface from contours only (point groups are better), what's the
BEST way to get a surface that represents the contours in the drawing?? My
first few attempts resulted in the contours crossing boundary lines and I
even had a few contours that crossed other contours!

Any input that anyone can give will be greatly appreciated.

Thanks in advance!


Matt W
"What am I gonna do with 40 subscriptions to Vibe?"

[Anonymous]

Or even an XML file.


"Matt W" wrote in message
news:5049176@discussion.autodesk.com...
I'm having one heck of a time with this one...

I work for an engineering firm. We get the survey information from one of
three places: The surveyor, the landscape architect or, God forbid, the
Architect (depending on where we are in the chain of command of any given
project). When we get the survey, 99.9% of the time we only get a DWG with
maybe AEC contours but mostly PLINES with a Z elevation. Getting the point
files or a DTM is next to impossible.

So, given everything that I've read to date regarding the no-no's of
creating a surface from contours only (point groups are better), what's the
BEST way to get a surface that represents the contours in the drawing?? My
first few attempts resulted in the contours crossing boundary lines and I
even had a few contours that crossed other contours!

Any input that anyone can give will be greatly appreciated.

Thanks in advance!


Matt W
"What am I gonna do with 40 subscriptions to Vibe?"

[Anonymous]

Hi Matt,
Most survey packages can create 3d triangles to represent the dtm. If you
import these 3d polylines into c3d as breaklines you will get a true
representation of the model.
I suspect the main problem is that the contours are design (by the Landscape
Architect or, heaven forbid, the architect) and are being drawn manually as
2d polylines. If that is the case, I would place the 2d polylines at
elevation and create points along them using the c3d point creation tools. I
would suggest a quick trip to the local pub prior to this.

regards,

Jon
"Matt W" wrote in message
news:5049176@discussion.autodesk.com...
I'm having one heck of a time with this one...

I work for an engineering firm. We get the survey information from one of
three places: The surveyor, the landscape architect or, God forbid, the
Architect (depending on where we are in the chain of command of any given
project). When we get the survey, 99.9% of the time we only get a DWG with
maybe AEC contours but mostly PLINES with a Z elevation. Getting the point
files or a DTM is next to impossible.

So, given everything that I've read to date regarding the no-no's of
creating a surface from contours only (point groups are better), what's the
BEST way to get a surface that represents the contours in the drawing?? My
first few attempts resulted in the contours crossing boundary lines and I
even had a few contours that crossed other contours!

Any input that anyone can give will be greatly appreciated.

Thanks in advance!


Matt W
"What am I gonna do with 40 subscriptions to Vibe?"

[Anonymous]

Thanks for all of your feedback. This helps a lot!!

Unfortunately not all pubs serve my beverage of choice: Irish Car Bomb.

Mmmmmm...... beer!

Matt W
"What am I gonna do with 40 subscriptions to Vibe?"

[Anonymous]

Hi Matt,

Now that Civil 3D can properly interpret 3D faces in a drawing file when
building a DTM from them, they would be my first choice. All Civil/Survey
software of which I have experience can output its DTM as 3D faces and so
you have only one working process at your end.

If you are working with Land Desktop to Land Desktop the DTM folder is the
best option. Points and breaklines (unless the breaklines are correctly
prepared are too risky and leave you with work to do).

If you surveryor has Civil 3D get a drawing with the DTM in the drawing.

--

Laurie Comerford
CADApps
www.cadapps.com.au
"Matt W" wrote in message
news:5049371@discussion.autodesk.com...
Thanks Laurie!

So what would be the BEST thing to obtain? The DTM folder from LDT?? A DWG
with the TIN?? The point groups (if any) that were used to create the
surface??

I don't think any of the surveyors or landscape architects that we deal with
have C3D. If they do, they're not using it. Most of the
engineers/architects/surveyors are still running 2000.

--
Matt W
"What am I gonna do with 40 subscriptions to Vibe?"


"Laurie Comerford" wrote in message
news:5049342@discussion.autodesk.com...
Hi,

Try harder to get the original surface. If you have AEC contours, then you
know someone has an electonic surface model.

The time you spend on administrative effort in doing this will reduce over
time as your clients come to realise your needs. Also you cannot guarantee
your work without the model.

Also you do not need to spend any engineering time trying to make a
reasonable model from the contours.
--

Laurie Comerford
CADApps
www.cadapps.com.au
"Matt W" wrote in message
news:5049176@discussion.autodesk.com...
I'm having one heck of a time with this one...

I work for an engineering firm. We get the survey information from one of
three places: The surveyor, the landscape architect or, God forbid, the
Architect (depending on where we are in the chain of command of any given
project). When we get the survey, 99.9% of the time we only get a DWG with
maybe AEC contours but mostly PLINES with a Z elevation. Getting the point
files or a DTM is next to impossible.

So, given everything that I've read to date regarding the no-no's of
creating a surface from contours only (point groups are better), what's the
BEST way to get a surface that represents the contours in the drawing?? My
first few attempts resulted in the contours crossing boundary lines and I
even had a few contours that crossed other contours!

Any input that anyone can give will be greatly appreciated.

Thanks in advance!


Matt W
"What am I gonna do with 40 subscriptions to Vibe?"

[Anonymous]

Laurie:
Thanks for all of your help regarding this matter.

--
Matt W


"Laurie Comerford" wrote in message
news:5050366@discussion.autodesk.com...
Hi Matt,

Now that Civil 3D can properly interpret 3D faces in a drawing file when
building a DTM from them, they would be my first choice. All Civil/Survey
software of which I have experience can output its DTM as 3D faces and so
you have only one working process at your end.

If you are working with Land Desktop to Land Desktop the DTM folder is the
best option. Points and breaklines (unless the breaklines are correctly
prepared are too risky and leave you with work to do).

If you surveryor has Civil 3D get a drawing with the DTM in the drawing.

--

Laurie Comerford
CADApps
www.cadapps.com.au
"Matt W" wrote in message
news:5049371@discussion.autodesk.com...
Thanks Laurie!

So what would be the BEST thing to obtain? The DTM folder from LDT?? A DWG
with the TIN?? The point groups (if any) that were used to create the
surface??

I don't think any of the surveyors or landscape architects that we deal with
have C3D. If they do, they're not using it. Most of the
engineers/architects/surveyors are still running 2000.

--
Matt W
"What am I gonna do with 40 subscriptions to Vibe?"


"Laurie Comerford" wrote in message
news:5049342@discussion.autodesk.com...
Hi,

Try harder to get the original surface. If you have AEC contours, then you
know someone has an electonic surface model.

The time you spend on administrative effort in doing this will reduce over
time as your clients come to realise your needs. Also you cannot guarantee
your work without the model.

Also you do not need to spend any engineering time trying to make a
reasonable model from the contours.
--

Laurie Comerford
CADApps
www.cadapps.com.au
"Matt W" wrote in message
news:5049176@discussion.autodesk.com...
I'm having one heck of a time with this one...

I work for an engineering firm. We get the survey information from one of
three places: The surveyor, the landscape architect or, God forbid, the
Architect (depending on where we are in the chain of command of any given
project). When we get the survey, 99.9% of the time we only get a DWG with
maybe AEC contours but mostly PLINES with a Z elevation. Getting the point
files or a DTM is next to impossible.

So, given everything that I've read to date regarding the no-no's of
creating a surface from contours only (point groups are better), what's the
BEST way to get a surface that represents the contours in the drawing?? My
first few attempts resulted in the contours crossing boundary lines and I
even had a few contours that crossed other contours!

Any input that anyone can give will be greatly appreciated.

Thanks in advance!


Matt W
"What am I gonna do with 40 subscriptions to Vibe?"

[Anonymous]

I agree with this 100%. We were having a hard time getting an accurate surface built with the contours given by the Survey firm. SO finally myself and our owner sat down with the firm and told them if we didn't get the information required to do our design accurately we would put a note in the drawing holding them legally and financially responsible for any major in process design changes that would be needed.

The next day we had every TIN we had ever asked for.