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Thread: Issues with 3d terrains

  1. #21

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    This camera angle is probably a bit too low, but it shows the type of effect I woud want on a larger map.
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  2. #22
    Software Dev/Rep Hai-Etlik's Avatar
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    Quote Originally Posted by Jykke View Post
    Hai-Etlik, I'm not sure if the application I'm using (vue) enables me to do the type of projections etc you have mentioned. :S
    You could simulate it with an orthographic projection and then using a height map as a displacement map.

    Here's an example. Orthographic on the left, simulated oblique on the right.

    Click image for larger version. 

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    It'd probably just wreck your pretty picture, but it's worth a try. Getting proper oblique projection would work far better if you can convince the software to do it, or if you can export data into some other software that can.

    PS:

    Re: RobA's method. Just use the orthographic image as is, with lighting and all. Then use only ambient lighting in POV-Ray.
    Last edited by Hai-Etlik; 08-21-2009 at 07:57 AM.

  3. #23
    Administrator waldronate's Avatar
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    You can pseudo-project an image back from a 3D view to get a 2D view using the perspective and scale tools in Photoshop. The attached images show a trivial example in Wilbur.

    The first one is a basic 2D image generated from a height field.

    The next one is the height field and image from the first step in Wilbur's 3D viewer. The 2D distortion will eat a lot of resolution in the squished part of the image so I stretched the window to get it as large as possible. With a real 3D app you can render to a large resolution. (I overdid the 3D angle a bit so it's a little overtall for the mountains.)

    The final one is the middle image pulled into Photoshop and some basic processing done to it. I applied the perspective filter to pull the top of the image out until the sides were vertical. Then I used the scale operation to stretch the perspective-distorted image back to its original square proportions.

    This process gives you something like plan oblique relief from a generic 3D app with no need for special projections. It works better if you can put a bit of a horizontal barrel gradient into the height field before you render it. These techniques are from Tom Patterson's discussion at his web site (the http://www.shadedrelief.com site and http://www.shadedrelief.com/dem/dem.html ).
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  4. #24

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    Ok, I'll have to take some time and test these techniques out. Thanks for the advice

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