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I'm modeling a specific hill. I have a topographical map of the hill and wish to plot the 1 meter height contour lines accurately. What's the best way to do this?

I cannot find a tutorial like this on Blender, but found one for 3ds Max: https://www.youtube.com/watch?v=EVuY3dBYQfk (from 1:55).

The image below shows a model I made in sketchup; I created a plane, drew in the squiggly lines with its freehand line tool, then extrude.

enter image description here

enter image description here

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3 Answers 3

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Assuming your landscape is a mesh, you may try the following:

  1. add a plane a little bigger than your landscape, and at the base (or lower than) of landscape
  2. with plane selected, and under "modifier tab", you add an "array" modifier. You set to constant offset, X and Y to 0, Z to a distance that suits your needs, and you should increase the count to get as much planes as you need to cover the top (or pass a bit) of your landscape). If your landscape is in "real" scale, you can set the Z to 10m, to get the 10m isocontours.
  3. with plane selected, under "boolean" you set to "intersect" with the landscape
  4. apply your modifiers to the plane (you will have horizontal planes by choosen iso Z value)
  5. press "space", write "convert to" and select "curve from mesh/text" (you will convert the planes to lines, to get their perimeter - if you need, you can then increase thickness of lines, etc)
  6. optional step if you want to control the material (colours, etc) of your contours: you again "convert to" "mesh from curve/text"

Following the exact steps mentioned above you get the following result:

enter image description here enter image description here

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  • $\begingroup$ Thanks for your help. I'm new to Blender; I followed your instructions up to 3 and am a bit lost. How did you get the contour lines in? Is there a tool where I can draw them in? Because I need to trace them off an image file (jpg, png, etc). I added another image above to show how I did that big model in Sketchup; not sure if Blender has the same modeling process though. $\endgroup$
    – Silk
    Mar 28, 2020 at 7:27
  • $\begingroup$ considering your new information you can add "curves" than draw them along the isocontours. Then press "G", then "Z", to grab and move on Z axis, then you type how much you want to move (example: G then Z then 10m). When all iscontours are drawn, you select them all, and join them into a single object. Then you triangulate the surface. This way, in my opinion is not the most suitable. You should trace the isocontours on QGIS, assign a Z value for each, then export to obj, or directly in QGIS build the DTM. Follow the next instructions: makoj.com/blog/2018/april/contours-dem $\endgroup$
    – MCunha
    Mar 28, 2020 at 9:34
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In case you can't use GIS data directly and really want to create a model from image - draw lines ... you can use Trace Tool ...

  • drag&drop your image into Viewport (it appears as Empty Image)

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  • search for Trace Image to Greace Pencil operator, in edit mode selection vertex each outer side of line and hit L (Linked), X (Delete)

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  • with greace pencil object selected press W (Object Context Menu) > Convert to Polygon Curve and in edit mode select highest loop with L and move one level G, Z, 1, confirm ... with cursor close to second loop press again L, G, Z, 1 and repeat this process for all loops ...

enter image description here

  • search Convert to Mesh, go to Edit mode and with all selected, search Merge (M) from Distance, than search for Bridge Tool to generate surface

enter image description here

... or just extrude if you are looking for step elevation result.

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  • $\begingroup$ Thank you! I managed to figure out how to import the contours from GIS data for my previous project. But I will give this method a go next time. Cheers! $\endgroup$
    – Silk
    Dec 10, 2021 at 22:26
  • $\begingroup$ Sure ... Using GIS data is right efficient way (•‿•) $\endgroup$
    – vklidu
    Dec 11, 2021 at 6:52
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I am not expert, but seeing your detailed layers of planes extruding little by little like that, and they are not connecting to each other, I think you can use Bezier Curve, and add extrude to the Geometry tab. Or you can convert the curve into mesh and extrude them. For exact dimension of 1m, by default Blender is using meter, so 1 unit of Blender is 1 meter, check Scene Properties > Units.

So, this is simplified example from what I understand to what you want: Example terrain layers with extruded bezier curve The dimension is accessed from 3D View, press N to toggle show/hide it.

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