"The client is an engineer working in microstation who is looking for a "DTM" file."
This is describing a Digital Terrain Model from Bentley InRoads products. InRoads is a third party app running within the CAD engine of Microstation, just as LDD or Carlson are a third party running within the CAD engine of AutoCAD.
Therefore none of the suggestions on here have completely satisfied the required deliverable, as per the engineers request. Though with instruction the Engineer could try to create the InRoads DTM from the 3d faces, fault lines (breaklines) and spot points, or LandXML file as suggested here. But, I suggest you create a separate 3d cad file of only the breaklines and spot points to be used in the surface model. Then you can create your own test model from the same exact data to be verified with contours, profiles and sections. The 3d faces/triangles are useless in Engineering design. Engineeris need the breaklines to help with the design process. 3d faces, contours, profiles, and sections are end products of the original survey data, the breaklines and spot elevations. So always give them the original data with instruction as of what is to be excluded or included in the surface model.
FYI: I use Miscrostion and InRoads, along with Carlson products. If you want to consult with me on creating the InRoads DTM, please contact me lee@leegreen.com
LeeGreen.com
> The 3d faces/triangles are useless in Engineering design. Engineeris need the breaklines to help with the design process.
No. That isn't really right...
As long as the EG/OG surface is built correctly (which it is, by any competent surveying effort), the 3D faces are what you SHOULD be using. And this should be easy to transfer between any decent CAD package, be it C3D or Land Desktop or Carlson or the various Microstation flavors.
Correct breaklines are necessary to create the DTM. But once you have a correct surface built, you don't really need the breaklines anymore, in most cases.
There are times where it DOES get annoying. For example, in C3D, you can paste Surfaces together. And for a Surface designed using breaklines + points, the breaklines get "lost" in the pastes. This gets noticeable when you paste Design Surface 2 into Design Surface 1 which is pasted into the OG Surface. And that's actually been annoying for me in some projects, but only in maybe two projects in the last three years. So while I think this should be fixed in C3D, it's not as important as some other problems.
Sinc,
I don't know if you have ever worked in highway design or if you have ever used Microstation with InRoads, but it sounds like you have not. So I have to disagree with you as an instructor of InRoads products for over 15 years for NYSDOT, NJDOT and VTDOT. First off InRoads does NOT have an import surface from triangles or 3d faces as many of the Acad products may have. Also since InRoads is essentially a highway design application it is important for the designer to have original breaklines to perform analysis. For example: On a mill and pave project the designer may create a profile along the centerline of highway alignment. Then InRoads can show the top face of curb lines projected to the profile to compare the curb reveals. Also if the design is creating a detention pond around an existing basin, they will need to top and bottom of bank breaklines to start the design from.
Triangles, contours, cross sections, and profiles are by-products of the original surface data, which are breaklines and spot elevations.
Put it this way. If the engineer were to give the surveyor a proposed highway to layout, would you want 3d faces or 3d breaklines?
Lee Green
If you were to send the Engineer 3d faces or triangles it is best to use LandXML format. InRoads can import surface via LandXML.
Our guys are running Geopack on V8 and claim they cannot use XML files. (Don't really lnow if they "can't" or if they "do not know how". Anygraph users are not the sharpest crayons in the box. ;o) )
"The client is an engineer working in microstation who is looking for a "DTM" file."
This is describing a Digital Terrain Model from Bentley InRoads products. InRoads is a third party app running within the CAD engine of Microstation, just as LDD or Carlson are a third party running within the CAD engine of AutoCAD.
Therefore none of the suggestions on here have completely satisfied the required deliverable, as per the engineers request. Though with instruction the Engineer could try to create the InRoads DTM from the 3d faces, fault lines (breaklines) and spot points, or LandXML file as suggested here. But, I suggest you create a separate 3d cad file of only the breaklines and spot points to be used in the surface model. Then you can create your own test model from the same exact data to be verified with contours, profiles and sections. The 3d faces/triangles are useless in Engineering design. Engineeris need the breaklines to help with the design process. 3d faces, contours, profiles, and sections are end products of the original survey data, the breaklines and spot elevations. So always give them the original data with instruction as of what is to be excluded or included in the surface model.
FYI: I use Miscrostion and InRoads, along with Carlson products."
No, we cannot send then a DTM directly, but we can provide them with the data from Carlson to REBUILD that surface accurately. If given the 3D breaklines, tin triangles and a coordinate text file, they can indeed recreate the DTM files in Microstation. Our guys are doing it everyday with just that data.
Matter of fact, in areas with no real breaklines (bottom of sludge ponds, etc.) they can take just the Carlson triangyulation data (tin triangles)and recreate the surfaces and contours. Again, our people are doing this on a daily basis.
Staked many a Dtm Excavations Very Strange Shapes
with Carlson Survey CE On carlson Survey + DC
I would build the surface from 3D polylines to make the tin edit the
tin IE flip faces and other small subject eye adjustments. Then Explode the surface to 3d faces.
THis is done to make the edits history from C3D the surface removed, surface is still corerct and unchanged just what you see is what you get edits history are in but cannot be undone.
Then next DXF to Carlson DC import 3Dfaces and stake away with the gps to control excavators. The DXF inport is way quicker than XML or dwg import and the files much smaller.
THe XML import in CARLSON DC does not support the edit history in C3D XML out and the surface that is import to via DC is missing edita like holes punched in a surface
done in C3D Yikes. So I found it better to explode in C3D the surface to dumb down the surface so for example the hole mentioned above would import via DXF to Carlson DC would be there.
If i requested a dtm from the engineer i would ask for CAD with fault lines (3d POLYS) and MOSTLY dumb 3d Faces for that is what CARLSON DC uses best and i guess most machine control systems.
Peter K
Are we using the surface to design on top of or for dtm stake/machine control
Design = every thing 3D polys + Tin (DTM) and planimetry ie everything..
Construction = 3D Faces may a few critical 3 polys and alignments each job
might use templates then and a few DTMs a odd area to make the finished shape.
Peter K
3d faces are fine to design from for they are from Breaklines.
Even with breaklines after the surface is built i still flip a few faces in 30 thousand faces to fine tune the surface so the TIN ( 3d faces "TIN" is the finished product) then i send it to the engineer with C3D DTM CAD with Planimetry plus PDF and nice border the works.
I would say that 100% of Design cad could import 3 D faces on import and the DTM would agree with the original 3 d poly breaklines the faces where built from.
XML is a mine field for some cad imports do not supoort edit historys well and the imported tin is missing some things like etc etc.
Fault lines and planimetry should appear on the plan that define the DTM = 3D FACE
topo plan if the end use program cannot support XML or other DTM imports
Just send them 3D FACES and a plan with fault lines and contour the usual planimetry etc Plus PDF.
PK
3d Faces per surface
maybe a alignment or two