Creating a terrain with the real elevation values

Dear all,
I have imported 3D contour lines and I want to create the terrain from them. Here there are:

Curve_5m_smooth.DXF (8.5 MB)
They are seen as 3D and have the right positions while imported, however the elevation that they show are not correct. For example, a line that has a Z=700m, is shown as 300m. I need each line to show the real Z value since I have the rest of the model created based on the real elevations.
I did not select ‘Preserve drawing origin’ check box while importing because I cannot find the where the lines are if I check it. Is this option related to changing the elevation values automatically? Thanks

Is the Z dimensions the only one out of scale? Are the X and Y not proportionally out of scale too? Is this not a case of scaling the imported geometry. I cannot find elevation numbers on the imported lines, is that information elsewhere?

Set meters on Import > Options (after you select the dwg/dxf file)
meters

If the scale is still incorrect after import with the proper units set, you can resize the geometry from a known dimensions. Import the topography, explode it and make a component of it. Then measure a known distance with the tape measure, like between two elevation lines, then type the desired distance into the VCB. You will be asked if you want to resize the model, say yes.

I have selected meters @mihai.s.
@endlessfix no the X and Y correct show the correct area. I do not know how to show the numbers in Sketchup. but if you open it in Autocad, it shows the elevation values. For example the last line on lower left corner has 615m altitude:

But here it is shown in:

So the scale of the imported geometry is correct, but the z location is incorrect? Grab the topography by a known elevation line, and move it in the z direction down until the line is at 0 elevation. Then move it again in the z up to the desired elevation by starting a move and typing the z value.

This may place your geometry very far from the origin which can make the model operate poorly. Distance from origin is not the same as real world elevation data.

It makes sense to be like that, because you didn’t check "Preserve drawing origin’.

Do as endlessfix wrote, because you can’t work with the terrain positioned far from origin in SketchUp.

2 Likes

As @mihai.s says this option will bring in the geometry relative to the origin, you probably cant find it because it’s very far above the origin. Hitting zoom extents would reveal the location of the imported topography. I’m not sure this is the best option, as you would needlessly be working so far away. I guess I don’t quite understand what you are trying to match. Are you saying the rest of your model is 700m away from the origin?

1 Like

Thanks @mihai.s and @endlessfix . I selected the ‘185m’ line and moved the whole model up based on the difference between the real elevation and the Z that sketchup showed 615-185=430. So now all are correctly placed next to origin.

2 Likes