Help needed with Contour Lines both imported and exported :)

Hi, I would love some guidance using Sketchup Pro for mapping the terrain of our 20-acre land :smiley: Apologies for the lengthy post but all these issues are related and I truly need help ASAP with this.

I got contour lines 1ft apart (our land is quite complex and I need as much detail as possible) generated by LiDAR imaging. I got them in a DWG file, which I could easily import to Sketchup Pro, but I have lots of issues I hope someone here can help me with. :slightly_smiling_face:

  1. Once the DWG is imported, I see the number of edges are huge more than 200K. So I cannot explode it and much less use the From Contour tool. :rofl:
    But my newbie workaround (I just got Sketchup :wink: ) has been to “Edit Component” and delete edges in sections, so I get a section of 10K edges or less, then I can explode that and use the From Contours to generate my precise Terrain. I imagine that in order for me to do this with all the edges, I would have to create a layer for each section of 10K edges and this would be a HUGE job, and I would need them all to be later be grouped.
    Any suggestions on how to work with this kind of file in a more simplified way? Please note, I do not have access to AutoCad, or other software only Sketchup.

  2. The other major problem I have not found a workaround to, is that the imported DWG file, which is ALSO Geo-located, shows up not at the same scale as and hovering 54 feet above the Geo-located terrain that I created with Sketchup (I did this at the highest zoom possible 18). - See images attached please.
    2a. Why is this happening?
    2b. How can I fix this?

  3. Also I need to export the contour lines to Google Earth Pro, which I can do easily, even the humongous original component without changing it :), but again, when I do that it has it floating up high from the land. I guess if I fix number 2 above this will get fixed too, but I am asking just in case there is a different thing I need to do. - See images attached please.

  4. Now, from the TOP view, the LiDAR contour lines match “almost” perfect (once I scale manually the whole component uniformly with the Scale Tool) to the Terrain generated by Sketchup. Almost! But, when I try to correct manually the fact that my imported lines are hovering 54 feet above the terrain Sketchup generated, by moving the contour lines with the Move tool to the Red Axis, which in the Geo-located Terrain seems to be right at the middle of the terrain horizontally and vertically, the LiDAR generated contour lines do not seem to match at all to the terrain generated by Sketchup. Why?

  5. So, I thought I would generate the Contour Lines from the Geo-Located terrain generated by Sketchup (soft mesh) and they are quite different to the ones from LiDAR. This makes me question, please remember I I’m a newbie with Sketchup :sweat_smile:, will the work I do on Sketchup NOT match our land? I need to know if I can rely on Sketchup to design our land. I need to identify slope, aspect, how the water runs in the land and where we can establish ponds, and dams and how to re-route water to where we will need it and more! At the moment the land is just wilderness and I will be using Permaculture principles to design it. :smiley: - See images attached please.

  6. And last, when I export the contour lines I generate from the Geo-Located terrain in Sketchup into Google Earth Pro, it is as if the contour lines are intersecting in SOME areas below the Google Earth graphics and in other areas the contours just float above too; and in a section, no lines where imported but a full polygon! The Geolocation is perfect though. How can I fix this? Again, won’t the models I create in Sketchup be precise? Am I missing something in the way I export the 3D Models (at the moment just contour lines)? - See images attached please.

I hope someone can help me with these issues. :slight_smile: mile: . Again apologies for the lengthy post. (my first) I hope it is Okay, if not, should I post each question separately?

Thank you!!! :pray: :heart_decoration:

Helena

First off I would recommend checking out this course on Sketchup Campus - 3 Ways to Boost Your CAD to 3D Workflow

Especially Section 3 about cleaning up a CAD model without CAD in SketchUp.
There is a lot of detail about really powerful extensions that help clean up that linework.

If you are a newbie, I would recommend checking out more of the courses on SketchUp Campus or SketchUp’s Youtube since your workflow is somewhat intense for a new user!

Adding your files to this thread will also help folks address your questions.

Thank you, Kyle :smiley: :pray: I will check out the Boost your CAD to 3D workflow WITHOUT access to CAD software. :slight_smile: but extensions.

Before posting here, I did watch, for the last week, lots of YouTube videos from Sketchup (great tutorials!) and also a few from other people; but I gave up today and decided to ask here :sweat_smile: . In none of those videos and articles my issues were mentioned or addressed.

I did originally add 6 different files, but because I am a “newbie” in the forum I was not allowed and I had to group them all in the one file that I was allowed to upload. I will add new ones here to the thread as you mention, if my troubles persist. Thank you!

In the attached image here, you can see how vastly different are the LiDAR countours compared to the Fine Mesh and to the contours produced using Sketchup (left side of the terrain). Do you know why is that?

And also, why the contours generated by Sketchup intersect so low with the Google Earth Pro?

I’ll jump onto that course now… hopefully my answers regarding the CAD file will be there.

Thanks again! :pray:

Helena

How did you generate the “geo-located DWG file”?
What did you use to get the LiDAR?

While SketchUp and Google Earth can show terrain, they are by no means as accurate as a survey done by professionals.

Most often surveys use an xy-type map coordinate system used by local maps that differs from the lat/long system used in the SketchUp geolocation and Google Maps/earth.

Hi Kyle, :smiley:

I got it from USGS LiDAR. This is the information I found regarding the file I have:
“…produced exclusively from high resolution light detection and ranging (lidar) source data of one-meter or higher resolution. The spatial reference used for tiles of the one-meter DEM within the conterminous United States (CONUS) is Universal Transverse Mercator (UTM) in units of meters, and in conformance with the North American Datum of 1983 (NAD83). All bare earth elevation values are in meters and are referenced to the North American Vertical Datum of 1988 (NAVD88).”

The good news, as described earlier, is that I can open the file in Google Earth after I export the Model from Sketchup. But I don’t know how to bring the model “down” to ground zero. That option is not available for files imported from Sketchup. Maybe, just bring the whole component down on the Z axis and export to see if it works.

Now, with my other issue, trying to form the terrain in Sketchup from the LiDAR countours I have. I took the course you recommended but sadly, that didn’t offer solutions to me. It was very interesting and good but does not apply to terrain. I downloaded the extensions recommended but they don’t work on my contour lines.
That said, I was lead to other potential solutions. I found that TopoShaper allows me to “explode” the gigantic file (1750000 edges) without crashing. Now I am trying to generate the terrain in sections. I hope that works LOL

If you have any more inspiration, please let me know. :slight_smile:

I appreciate your support!

Thanks! :pray:

Hi Anssi, thanks for your reply, apologies for forgetting to address it. The file I got with the contour lines uses Universal Transverse Mercator ( UTM) in units of meters , and in conformance with the North American Datum of 1983 (NAD83).
I didn’t get it from a survey, just what is available from ESRI. :slight_smile:

If you can get a 2’ interval map, I"d use that. Simplification via Toposhaper might help. I usually simplify beforehand in CAD.

You haven’t said what sort of project you are doing this for, and I don’t know your purpose of using the data in Google Earth, so keeping that in mind, my experience with modeling building projects in SketchUp terrain models:
I doubt the higher resolution (getting every point) of the LIDAR contours is valuable, even IF it is that accurate. In the end it is still an approximation. The surface you make will be a greater (less accurate) approximation of reality (that’s why it creates different contours). Still it should be more than sufficient for your model. I think people worry about details of contours when they are only a computer generated expression from points, and not reality.
There’s no use in creating overly detailed and complex topographies (of approximate measurements) and overly heavy SketchUp files that you can’t manage. Unless perhaps you have truly accurate data and are doing archeology or some scientific work. In such a case you shouldn’t be using SketchUp.
Keep in mind that whatever you are building, the contractor will have bulldozed the site out of recognition in no time.

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You need a survey to be accurate. All those GPS resources are not detailed enough for building design. Some are +- 10 feet or more.

Thanks for your reply. I didn’t get an alert about your message.
I need this to create a Permaculture Design in 3D for our 20 acres land. The land is very complex, it has 3 hills in it with some cliffs. It also has two large lakes.
I don’t have access to autoCAD or to edit the autocad files I got. I am still trying to find ways to simplify the contours somehow before bringing the files into sketchup pro 2022.

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Thanks. :slight_smile: I am not designing buildings :slight_smile: But our land. Using Permaculture.