I try to give you 1:1 instructions ... as I skipped
a few steps for a good setup:
1. Get you PoV
2. Last shader should be an image map shader with a bright coloured bitmap (i.e. pure Pink)
3. keep the image map to camera projection and use your render camera (the whole field of view (FOV) turns pinkish ... good
)
4. Create a new camera turn it 90° down and place it over your area of interest with use 'Orthographic'
5. plug the orthographic camera into your render node and change the image width and height to i.e. 800 / 800.
6. Move the orthographic camera around and adjust its width until you get the most of the pinkish area into the view.
7. Write down the width of the ortho-camera and its position, these will be the values of your new heightfield.
8. Plug your render camera back into the render node and delete that ugly image map shader of Step 2
9. Create a heightfield shader and add a 'Heightfield generate' to its 'Heightfield'-input
10. Disable the 'Flatten surface first' in the heightfield shader (I am not sure!?!?!)
11. Disable the 'Fractal detail' in the heightfield shader
13. In the Heightfield generate do the following:
13.a. The size in metres is the width of the ortho camera
13.b. The numbers top if these are the resolution of the heightfield use i.e. 4096 and 4096
13.c. I do not know if this is necessary, but I always set the 'Feature scale' to 0 ... same with the variation in the Tweak-tab
13.d. in the 'Use shader' tab ... plug in your terrain .... insert the location of that ortho-camera
13.e. I am not sure, but I would set the Position to center.
13.f. Press the generate now button
13.g. After the build process do a right click on the Heightfield generate-node and do a 'Save file as ...'
13.h. Save both Ter and Exr ... keep an eye on the file-extensions.
14. Delete the heightfield-generate and add a heightfield-load, load the Ter file of 13.h.
15. You might need to set the position of the heightfield in the heightfieldshader.
16. Into the blending shader of the heightfield plug in a new imagemap shader, use camera projection and the ortho camera.
17. Load the .Exr-image (or converted to BMP, etc.)
18. I hope that I did not forget anything
Volker