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Unreal Engine 4 Mosaic import issue: gap between terrains

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Unreal Engine 4 Mosaic import issue: gap between terrains

Postby Hank Feez » Sat Aug 09, 2014 7:50 am

Hello,

I purchased a professional L3DT license last week in order to use it in conjunction with Unreal Engine 4 for a game I am making. My basic workflow is to make large maps in L3DT and then export them as mosaics and stitch them together as separate levels in the world composition tool. I ran into a couple issues on import, like what tile size to make, that I managed to fix, but one issue remains.

There is a vertical (purely vertical meaning no x or y offset only z as in altitude in UE4) gap between height map tiles in my imported mosaic. The gap appears to vary by the rate of change in the height map (meaning that the vertical distance between the height maps is not continuous along the edge of the tile). Initially, I was not using "duplicate tile borders" and the gap was larger. Now I do use it and there is still a gap but it is smaller. I have tried everything I could think of to no avail (I have created over twenty different mosaics to test different theories). My best guess is that the PNG file format (I tried both PNG and RAW format properly setup according to the UE4 documentation) somehow is not capturing the vertical range of each tile correctly, and as a result tiles differ in their vertical edge matching as a function of their difference in height range, but of course I know very little on the topic.

I took numerous screenshots of the issue (attached) and I have sample PNG files, but of course you would need UE4 to see the issue there.
corner of tile 2 - 1.JPG
Screenshot of a 4-tile intersection
corner of tile 2 - 1.JPG (23.12 KiB) Viewed 27186 times

corner of tile 2 - 2.JPG
2nd corner with same tile highlighted
corner of tile 2 - 2.JPG (40.32 KiB) Viewed 27186 times

front view - gap 3.JPG
front view of intersection of tiles (orthogonal view)
front view - gap 3.JPG (102.9 KiB) Viewed 27186 times


(I've never posted on here and that's all the files I'm allowed to attach I guess so yeah...)

Can anyone offer any advice as to how to get the tiles to match up?
Hank Feez
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Re: Unreal Engine 4 Mosaic import issue: gap between terrain

Postby Aaron » Wed Aug 13, 2014 9:49 am

Hi Hank,

I'm sorry for the delay in my reply. If the displacement is small relative to the horizontal vertex spacing, then this might be due to the compression in the HFZ file format, which allows a small height encoding error (by default, plus or minus 1% of the horizontal scaling).

The clearest way to test this hypothesis is to:
  1. go to the 'File->Format preferences' option in the L3DT menu,
  2. select the 'Project maps->Heightfield->HFF (L3DT)' tree option,
  3. Press the 'options' button, and set 'DataSize' to 4 and 'FloatFlag' to true (double-click to edit these values), then press OK to clear the options window,
  4. press the 'Make default' and 'Use format' buttons, and 'OK' to clear the format preferences window,
  5. re-generate the heightmap, and;
  6. duplicate the tile borders again.
Using the old HFF format in floating point mode means there is no possibility of compression-related quantisation errors.

Please let me know how this goes.

Best regards,
Aaron.
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Re: Unreal Engine 4 Mosaic import issue: gap between terrain

Postby Telarus » Sat Aug 16, 2014 10:50 pm

Hm, haven't jumped into mosaic maps with UE4 yet, very interested as well.

Nice to see another UE4 user on the forums, welcome aboard. :)
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Re: Unreal Engine 4 Mosaic import issue: gap between terrain

Postby Onkelpoe » Thu Sep 18, 2014 6:42 am

got similar problem with .raw in Unity 3D...
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Re: Unreal Engine 4 Mosaic import issue: gap between terrain

Postby Aaron » Sat Sep 20, 2014 4:17 pm

Argh! I just noticed that "duplicate tile borders" is partly broken. Some time ago I changed the coordinate mapping in the linear interpolation function in the map class to fix a bug elsewhere, and it seems to have had the unexpected side-effect of preventing "duplicate tile borders" from working fully. Fix on the way...
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Re: Unreal Engine 4 Mosaic import issue: gap between terrain

Postby Aaron » Wed Sep 24, 2014 2:23 pm

Hi All,

The 'Duplicate tile borders' function has been fixed in L3DT Professional v14.09 beta 5 (24th of Sept 2014), which is on the Pro downloads page now. Please let me know if you find and problems with the new build. Please accept my apologies for not finding and fixing this bug earlier.

Best regards,
Aaron.
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Re: Unreal Engine 4 Mosaic import issue: gap between terrain

Postby blacknibolion » Tue Nov 01, 2016 4:45 am

Please how do I import my tiled normal maps to ue4?
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Re: Unreal Engine 4 Mosaic import issue: gap between terrain

Postby Dude » Sat Mar 03, 2018 6:15 pm

Aaron wrote:Hi Hank,

The clearest way to test this hypothesis is to:
  1. go to the 'File->Format preferences' option in the L3DT menu,
  2. select the 'Project maps->Heightfield->HFF (L3DT)' tree option,
  3. Press the 'options' button, and set 'DataSize' to 4 and 'FloatFlag' to true (double-click to edit these values), then press OK to clear the options window,
  4. press the 'Make default' and 'Use format' buttons, and 'OK' to clear the format preferences window,
  5. re-generate the heightmap, and;
  6. duplicate the tile borders again.
Using the old HFF format in floating point mode means there is no possibility of compression-related quantisation errors.


Hello, my first post!

I use L3DT in Unreal Engine 4.18.3. With single terrain no issues, works great. But I need tiled world and here goes problems.
When I import tiles (after changed names x0_y0) it imports correctly, however levels are not adjusted with gaps.

Here correctly imported tiles, but with gaps:
Image

So I did quoted changes in L3DT. Firstly, I recreated old terrain project, then trying new smaller just with 4 tiles.
Now I can't import terrain to Unreal Engine, message here:
Image

here is x0y0 tile, maybe original image can help, however this is uploaded to imgur, I hope no changes in file format:
Image

here my settings:
Image

I have more questions, but other kind, so I will post it in new thread.

Thank you!
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Re: Unreal Engine 4 Mosaic import issue: gap between terrain

Postby Dude » Sun Mar 04, 2018 12:18 am

Update to my question.

I ask in few places and did own research.

Gaps:
Because few reasons, gaps can be created even with tiles adjustment and for now, only and working solution is to use smooth tool for terrain. It not only smoothing terrain but also sewed parts together. Some additional manual work, but less than looking for perfect automatic solution.

Not imported tiles:
Tile size must be in sizes recommended by epic, only this works. Following this guide https://docs.unrealengine.com/latest/INT/Engine/Landscape/TechnicalGuide/index.html#recommendedlandscapesizes it can be only:
127x127, 253x253, 505x505 etc.
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