Create a DTM

I am quite sure I will miss a step or three since I am attempting to do this from what memory I have left (and not actively creating a dtm as I type), but here goes:

Create a border (with a polyline) connecting all the points at the outside of the area.

Tell AutoCAD the point numbers to be included (and perhaps excluded if any fall within the dtm area) in the DTM area

create breaklines for features

create surface

(Let me guess, you are looking for the specific commands instead of a general overview :'( )

> I am quite sure I will miss a step or three since I am attempting to do this from what memory I have left (and not actively creating a dtm as I type), but here goes:
>
> Create a border (with a polyline) connecting all the points at the outside of the area.
>
> Tell AutoCAD the point numbers to be included (and perhaps excluded if any fall within the dtm area) in the DTM area
>
> create breaklines for features
>
> create surface
>
> (Let me guess, you are looking for the specific commands instead of a general overview :'( )

Thank you for the response. You've described building the surface correctly, which I understand well.

The client is an engineer working in microstation who is looking for a "DTM" file. ACAD creates a DTM folder with separate files like *.tin, *.pnt, etc. But I get the feeling this guy is looking for a single file that he can import - I don't have much experience with microstation so I'm trying to figure out what he needs from me exactly.

I am assuming that you alreadt know how to build your project surface and do the contours and all. If so, when you finish the surface, simply send then the DTM folder from your AutoCad project folder. All the info he needs is there. The client can then open your surface and proceed from there.

For a Microstation user....

Export as "3D Faces"

That's what he is looking for.

For a Microstation user....

> Export as "3D Faces"
>
>
> That's what he is looking for.

Thank you, that is helpful. But, I'm working in LDD3, and not Civil 3d. Any idea what command I can use to do this in LDD3?

For a Microstation user....

If the engineer is using Geopak or Inroads, a LandXML can be imported quite easily as a working surface.

Do you know what the surface is going to be used for? Quantities or maybe machine control?

He needs your SRF-FAULT, SRF-VIEW layers and your coordinate file to recreate the surface in Microstation. That's what I have to give the Anygraph guys in my office.

Mr. Apple,

My clients ask me to export an XML file, which includes points, breaklines and other information they can use to import my surfaces into the drawing files I send them.

I did not see this mentioned in the other responses.

JA, PLS SoCal

If you create the 3D faces when you create the tin file, save out to another drawing that has only the surface with 3D faces. Give him that dwg and associated surface files; he can open that directly in Microstation.

Hope you are charging accordingly.

I'm thinking he wants a landXML file. You should be able to export your surface data to a LandXML file.

I do not think Land XML files are compatable with Microstation. (At least our guys don't think so. They say they have never done it that way in V8.) My Microstation guys want the SRF-FAULT, SRF-VIEW Layer data and a txt coordinate file from the AutoCad types. That gives them everything they need to build the surface.
Best bet=Ask your Client.

Thank you everyone for all the responses.

I agree on asking the client - I would just rather look foolish on this site before looking foolish in front of the client. 🙂

xml files in MicroStation

I have a client that uses MicroStation exclusively. We supply them with a 2d dgn and xml surface file. I don't know what they do with it (what sort of MS module they use), but they like them...as long as they were exported in U.S. Survey Foot and not International Foot...

Go to the terrain pull down and chose 3D Face. It should walk you through generating the TIN.

For a Microstation user....

If Geopak is being used, all they really need is a 3D file of the DTM triangles. They can extract the data they need to build a DTM from that. I do it all of the time.

Was it even possible to export LandXML in LDD3? If so, it must be a pre-v1.0 version of LandXML. I actually can't remember back that far, it's been so many years since I used that old a version.

You can import LandXML into v8i, but I think you may need Inroads/GeoPak/PowerCivil, as opposed to straight Microstation. (Not completely sure about that, though...)