TIN files and .pnts File

[darrell_kennedy]

Hi All,

I have seen similar posts to the question I am about to ask, but it developed into an ongoing discussion about contours and triangles, which I hope will not occur on this one. I digress. 

Background: I have the CAD drawing with the ACAD points in it. I also have the tin file. The drawing appears to have been exploded therefore all the contours are polylines. 

Initial action: I converted all the ACAD points to cogo points and created a surface from those cogo points. Did some edge swapping until the surface contours matched up with the polyline contours that came with the drawing. Its about 95% accurate. 

Problem and/or question: First question, can I bring in this tin file to compare the surface to the one I created, and just to see the surveyors surface as well? I do not have the pnts file therefore I attempted to export the points as a pnts file format into the same directory as the tin file, but this did not work.

Second thing, the surface I created using the points and matching to the polyline "contours", is not at the same elevations as the points. They are in the they are relative to 0 datum not whatever datum the surveyor used.

Main thing I am asking is about exporting these points somehow to bring in the tin file.... Im not sure if its PENZD, PNEZD, EZD, etc. And follow up if you wish (just for discussion) is about the datum problem.

Cheers,

dk

[BrianHailey]

Hi Darrell,

When you say, "I also have the tin file", what is this file? Is it an actual surface? Is it a point file from the surveyor? Is it something else completely? 

[doni49]

Since you asked that this not turn into a discussion about triangles and contours, I'll avoid that topic EXCEPT to say to anyone else who happens upon this thread in search of solutions to their own issue(s):  there are valid reasons why such threads turn into discussions on the merits of importing contours and "making the contours match" -- please be sure to read those other threads too.

Now having said that, if you import the tin as a surface, it SHOULD give you contours that look similar to what you've got from importing your converted cogo points.  But if you've got a TIN file, why do you need/want to import points to make a new surface?

I'm not sure I understand the last paragraph of your query.

[darrell_kennedy]

Brian,

The surveyor stated " I have attached attached the tin file we generated with the final contours."

Ultimately I will have to reach out and ask for the .pnt file along with the .tin file, but I am starting this discussion just to see if it is possible without the .pnt file.

[darrell_kennedy]

Don,

When creating surface from TIN, I go to import the TIN and I get the error;

"File(s) not found. Be sure both .tin and .pnt files are present."

Thanks,

Darrell

[rl_jackson]

If you survey has the TIN lines used to create the surface you can use them to recreate the surface, and that would be your best bet IMO.

You can also use the .tin file as well, but both the lines in the drawing and the .tin should produce the same results.

[darrell_kennedy]

rl_jackson

Understood, it is simple enough to just isolate the contours, create a surface, then select all the contours and add them to surface as breaklines. Each of the contours are actually polylines and they have the correct elevation associated with them, but when I bring them into the surface, the surface changes the elevation of the contours to to something incorrect... datum issue possibly.

[rl_jackson]

Most likely the surveyor that did the surface is using LDD hence the TIN and PNT files. So there should also be a layer called SURF VIEW or something along those lines with TIN Triangles, those should be used for the C3D surface not the contours. You'll get better resulsts and a smaller overall file size. Contour lines are a last resort.

Now if the TIN lines are not in the drawing the surveyor provided use the TIN & PNT file these will again provide a better overall surface

[darrell_kennedy]

Understood, but as stated in the previous threads, the .pnt file was not provided.

[rl_jackson]

I believe you will only need the TIN, been a while since I have import a TIN to C3D. Again you should have a layer of the TIN lines in the surveyors drawing that would be frozen. But the tin file should do the trick.

[jmayo-EE · Accepted solution]

If the tin file was produced by LDD you need both tin and pts file to get the import to work.

You may have a microstation tin file.....Which is not the same. If this is what you have open it in MS and export as xml. If it was sent to you ask those who sent it to export it.

The xml would have been a better delivery from the get go.

[darrell_kennedy · Accepted solution]

I attempted to use the Convert AutoCAD points to Cogo Points feature but for some reason during the manipulation the datum was busting and the points were being converted with incorrect elevations. My final work around was to use DATAEXTRACT to extract the points into a csv file. I then opened a new file, set the datum(NAD83) to the site, then brought those points in. I created a surface from those points. I then brought in the contours from the original file as a block, and did some line swapping to get the surface to match up with the contours. As not all contours were perfect, it was better that I could manipulate the surface this was way because some of the triangulation the surveyor had produced resulted wonky contours.  I then exported this surface to Land XML so that no one had this problem in the future when the surface was needed.

There are many ways to have done this, but this is what I found to be the best. The battle between surveyors and design engineers still remains.

Thanks all,

dk