Problems with egdes when making landscapes

[jasonsmith4]

Hi!

 

I am learning to create landscapes from DEM data and satelite images. I use 3ds max.

 

Problem 1:

 

I create plane with 1 miliion polygons, use diplacement modifier, add height map then scale gizmo a bit to correct edge distortions. Then I select edges of the plane and move them down and make them planar along z axis.

 

The result is looking bad as seen at next image, ugly lines, it should render normally, what can i do?

 

https://ibb.co/jNLmB6

 

Problem 2:

 

Plane has 1 million polygons and the height map is 8k pixel. How could i rid of the steps as seen in the following image? Should height map be higher resolution to eliminate distortions?

 

https://ibb.co/f1XcJm

 

 

Thank you !

[Nicolai Bongard]

Problem 1: Add a smooth modifier and perhaps the edges will render better.

 

Problem 2: The resolution of the image will have an impact of how large an area is considered "the same" - as in if you have a 2x2 pixel size image covering an area of 10x10 meters, there will be 5x5 meters areas that will be the same height (if all the pixels in the 2x2 image have a different value)

However what you are experiencing looks like a problem with the range of colors in your heightmap. If you height map is a jpeg it has 255 levels of height, as each pixel goes from 0-255. You could smooth out the problem with a turbosmooth modifier and add a noise modifier to add some randomness to the heights to make the steps less obvious.

[jasonsmith4]

Hi!

 

I managed to solve problem 1 - selected edge polygons and then deselected smoothing groups, that solved it.

 

I use .png height maps. The source sites are: Opentopography and USGS explorer. Both sites give source files, that are in 8 bit. I use high resolution maps. If I convert 8 bit source displacement map to 32 bit in Photoshop,scale it up, add some blur, will that help? I tested it and it looked the same.

[Nicolai Bongard]

The resolution is only relevant with regards to how large of an area will a pixel cover on your terrain - one pixel has one height value based on its colour, thus the area that pixel covers on your terrain will make all the verteces/faces/edges it covers that corresponding height. As i tried to illustrate in the previous post, even if your terrain is really big and has lots of verteces, if you apply a 2x2 pixel heightmap to it, all the verteces that a pixel of that map covers will be the same height.

 

From the looks of your posted pictures, the steps are visible, but the steps do not show clearly the individual pixels, so the resolution of your map is not the problem.

 

The problem you are having is that a heightmap uses 255 different values, from black to white. An 8bit image has that information, as it is just colors. Higher bit images will allow you to include information about the pixels other than color (transparency/alpha and whatnot), but the displacement will not take that information into account.

 

If your heightmap is generated from a high mountain, and you imagine viewing that from a sectional view/the side, you can divide that image from top to bottomn in 255 equal parts (those represent the 255 values of the pixels, from black to white). Mountains as a kid would draw them are usually pretty flat at the bottomn, then arches up to a peak, and goes down again on the other side. Allthough there may be some variaton on the flat/low parts, if the variation is not enough to cross from one value to another, it will get the same value as the other next to it.

If the mountain is not so high, the 255 areas (values) will be smaller and you may get more variation of values on the lower/flatter areas of the mountain.

 

As you can see, the problem you are having will not be solved with altering your map. You can however add a noise modifier to add noise in the areas that appear to be stepped, you can smooth out the areas, you can paint deformations and whatnot.

[maxryhan]

Try to add just a bit of blur inside displacement mod to smooth things would help I guess

[jasonsmith4]

Ok, thank yor for advice. Yeah,I understand it. 8 bit height map is limited to 255 step info, what is not a lot if I want more details, 16 bit would give me 65535 info, what is a bigger span for height map. I have to find high resolution map source with at least 16 bit data.

 

I thought if I converted 8 bit map into 16 in Photoshop, Photoshop would automatically fill in the gaps between pixel values, some average value between pixels and would give more data to my dem map, made surface more smooth. But I can achive same thing by adding turbosmooth or decay, blur in displacement modifier.

Edited February 7, 2018 by jasonsmith4

[Francisco Penaloza]

Ok, thank yor for advice. Yeah,I understand it. 8 bit height map is limited to 255 step info, what is not a lot if I want more details, 16 bit would give me 65535 info, what is a bigger span for height map. I have to find high resolution map source with at least 16 bit data.

 

I thought if I converted 8 bitmap into 16 in Photoshop, Photoshop would automatically fill in the gaps between pixel values, some average value between pixels and would give more data to my dem map, made surface more smooth. But I can achive same thing by adding turbosmooth or decay, blur in displacement modifier.

 

No, changing the bit depth inside of Photoshop won't give you more light/color information. If that information is not there from the beginning, there is no way for photoshop to fill those gaps. This effect is called clamping because it hits a limit and it stops there.

 

Having said that if you change the mode from 8 Bits to 16 Bits and then pain at 16 Bits, that will create more light information, but it won't be in the same scale/range of the original image, in other words, it will be a big mess.

 

The same thing happened time ago when people tried to transform regular Panoramas to HDR Panoramas. It never worked.