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I need to make a model of different water body types in a valley. Therefore, I wanna use a standard valley model from the landscape add on and put three objects in this valley. Sadly, I did not find how to fit these objects within the valley mesh (bad drawing of how it should kinda look like are included).

Maybe one has an idea, or maybe there's an easier way than with the standard valley thing?

valley rendered but with stripes

blender standard valley

drawing

drawing 2

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  • $\begingroup$ Could you provide your Blender file using blend-exchange.com, including an example of "the three objects" you would like to put ? I could not figure out of your drawing what these look like. Could you also explain what do you expect as "fitting" ? Is it about position, orientation, position, ... ? $\endgroup$ Commented Jan 17 at 6:04
  • $\begingroup$ Hey, thanks for your answer, I will upload the blender file - here another drawing maybe more clear? I want to fit the objects to the landscape valley so that the objects follow the natural edges of the valley and dont have sharp corners. $\endgroup$
    – Mirai
    Commented Jan 17 at 9:56
  • $\begingroup$ <img src="https://blend-exchange.com/embedImage.png?bid=WAGbQxK2" /> $\endgroup$
    – Mirai
    Commented Jan 17 at 9:59
  • $\begingroup$ @Mirai This text is supposed to be edited into your question. I took the freedom to do that. $\endgroup$ Commented Jan 17 at 11:26
  • $\begingroup$ @GordonBrinkmann , sry, thank you :) $\endgroup$
    – Mirai
    Commented Jan 17 at 12:09

1 Answer 1

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(Using Blender 3.6.5)

Objective

To model the water surface of a stream flowing downhill, coloured by types of flow. Results with colors

Approach

Extrude a Bezier curve following the bottom of the stream, after a slight vertical shift, to generate a surface larger than the valley.

Procedure

Step 1: Visualise the slope

Shading 1. In the Shader Editor:
1.1. The vertical coordinate Z of the landscape is recovered by combining Texture Coordinate and Separate XYZ nodes.
1.2. Z is input in a Wave Texture node which Scale parameter is adjusted to sample the valley of interest.
1.3. The result is iso-elevation contour lines.

Step 2: Draw the curve following the valley

Bezier curve first edition 2. In Edit Mode/Top view:
2.1. Add a Curve/Bezier object above the landscape.
2.2. Add more control points above the landscape also. Move these in (X,Y) directions and adjust tangents to follow the valley floor, using the contours as guideline.
2.3. To put these control points on the landscape mesh, add a Shrinkwrap modifier. Set Wrap Method to Project along Negative Z Axis. Select the landscape as Target. Check the Apply on Spline icon to project the control points rather than the curve.
2.4. Duplicate this Bezier curve, to keep a copy before destructive actions, and Apply the modifier to the copy.

Step 3: Extrude the duplicated curve to model water surface

Edit copy 3. In Edit Mode, using the Curve Context Menu:
3.1. Select Set Handle Type/Aligned if the projection at step 2 misaligned left and right handles, to keep a smooth water surface whatever the underlying landscape slope variations are.
3.2. Set the Tilt of all control points to 90 degrees.
3. In the Object Data Properties panel:
3.3. Set Twist Method to Z-Up to keep extruded segments horizontal.
3.4. Adjust the Geometry/Extrude value, avoiding overlap of extruded faces in regions of small radius of curvature. Otherwise, stairs are generated instead of a smooth surface.
Adjust control points Z coordinate 3. In Edit Mode:
3.5. Move each control point in Z direction, or perpendicularly to the landscape mesh, to adjust the width of the apparent water surface.
3.6. Adjust tangents to keep the surface aligned with the underlying landscape slope, or to create horizontal lakes.
3.7. Using the Curve Context Menu, adjust the Radius at control points where the extruded distance is too small/too large according to the local stream width.

Step 4: Specify different materials/colours

Material selection 4. In Object Mode:
4.1. Convert the extruded curve from step 3 to Mesh, keeping the original.
4. In Edit Mode, using the Material Properties panel:
4.2. Select faces sharing the same type of flow.
4.3. Select a material and Assign it to the selected faces.
4.4. If a mesh per type of flow is required, from the Face Context Menu choose Separate/By Material.

Resources

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  • $\begingroup$ Thank you very much! I will try this - and is it possilble to divide this area (with coulours f.e.) into three different sections? $\endgroup$
    – Mirai
    Commented Jan 19 at 7:54
  • $\begingroup$ @Mirai: Would you like to apply different materials to the same mesh, or would you like to split this surface into three distinct objects ? In any case, do you have a criteria (elevation ?) to position the cut ? $\endgroup$ Commented Jan 19 at 11:19
  • $\begingroup$ good question - I now tried to reproduce all your steps - and it worked - I dont know what makes more sense, maybe three dif. objects? This is for a project in ecology to showcase specific types of flow through wetlands in a valley - I want to have them in different colours. $\endgroup$
    – Mirai
    Commented Jan 19 at 11:50
  • $\begingroup$ thanks a lot - one more question, if I render the thing as it is, weird stripes appear in the colored areas. $\endgroup$
    – Mirai
    Commented Jan 21 at 10:21
  • $\begingroup$ Could you check that in the Outliner, only the last mesh is enabled in Render mode, and that the shrinkwrap and extruded objects are disabled in Render mode, before rendering the scene ? In the provided Blender file, I forgot to disabled both, so these are invisible in the 3D Viewport but show in rendering. Sorry about that. $\endgroup$ Commented Jan 21 at 15:40

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