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I haven't thought of it before, but is there a way to map a terrain evenly? What I would do is subdivide a plane, asign to it a texture and then sculpt it to make it uniform. But, from the sculpting process the texture suffers as a result because it stretches as I sculpt. Here's what I mean (These are low poly examples just for demonstration, but with high poly count they can be made to look the same, but the texture suffers) - What I do -

enter image description here

How I think should be done -

enter image description here

As I do it (image 3) if the terrain was flat, the texture will be evenly mapped along the mesh.

enter image description here

But on a bumpy terrain the texture will stretch (Image 4)

enter image description here

That wouldn't happen on an even topology (image 2).

Is this a topology issue or a mapping issue? Is there a solution for this?

Note - I want to map a terrain without squishing and stretching at all. Is it possible?

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  • $\begingroup$ that would still happen even on an even topomogy, because you are using the undistorted UVmap for the sculpted plain $\endgroup$ – Chebhou Jul 27 '15 at 12:29
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That wouldn't happen on an even topology (image 2).

Yes it would.

Sculpted surface has a larger area than the flat one, stretching is inevitable.

What you wanna do is to sculpt the surface first, then texture it with Clone Texture brush and bake the texture. That way it won't be stretched on the model but instead as a result it will be stretched/squashed in UV editor (which is fine).

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  • $\begingroup$ I kinda thought of that at first, but I thought there would be difficulties with other maps if they have to be equally mapped. I guess its not as hard as I thought. Thanks :) $\endgroup$ – Vladimir Jul 27 '15 at 12:38
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Another way to get a nice texture without stretching is to use box mapping. It basically projects the texture onto your geometry from the sides of a box with the option to add some blending where the texture's edges meet. It often works well with organic textures. There's an option for it in the image texture node. You don't need to create a UV map for this. enter image description here

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  • $\begingroup$ Projecting a texture means stretching it. Box mapping DOES stretch images. $\endgroup$ – Jaroslav Jerryno Novotny Jul 28 '15 at 10:48
  • $\begingroup$ That's correct a little bit of stretching is unavoidable. Not particularly noticeable stretching would be more appropriate. $\endgroup$ – user40079 Jul 28 '15 at 11:45
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Unfortunately, the distortion which occurs when 2D textures are applied to 3D geometry is unavoidable. When the changes in elevation in the terrain are gentle—about 40 degrees from the horizontal, or less—the distortion is usually small enough that it can be overlooked. When the slope is greater, I find it necessary to add additional geometry to deal with the distortion. This illustration shows how I dealt with an extreme case

dealing with stretched geometry

The left half of the image shows the feature as originally modeled; the blue and yellow is a preliminary texture and will be replaced with a suitable rock texture. The right side shows the feature with the additional geometry which will be fit into the bit on the left. More information is in my answer to a related question.

In some cases in addition to modifying the geometry, it may be necessary to modify the texture, or choose a different one.

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