Terrain Mesh Blending

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Mistahtokyo
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Terrain Mesh Blending

Post by Mistahtokyo » 17 Jun 2016, 14:05

A picture's worth a thousand words.
Image

Image

How feasible would this be? I always found that, regardless of the other effects and eye candy the one thing that always stood out to me (in a bad way) with Bethesda games was their meshes, particularly their borders. They can be so jarring at times, makes it look like the world is made out of mismatched Lego pieces cobbled on top of one another.

Edit: In game example of how jarring it can be. Take a look at the rock edges.
Image

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Ravenwing
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Re: Terrain Mesh Blending

Post by Ravenwing » 17 Jun 2016, 20:42

OHMYGOD yes please! That's one of the things I can't stand. But these look gorgeous, although I think we would want a way of turning it off on some statics. A mesh blending toggle would probably be trivial in comparison to the actual mesh blending effect. Do other games use this? Do we know how it affects performance?

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Ace (SWE)
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Re: Terrain Mesh Blending

Post by Ace (SWE) » 17 Jun 2016, 21:58

So basically, the ground texture applies onto any geometry intersecting the ground - like a decal?

Got any more information about such a thing, a link to a paper about implementation possibilities for instance?

ezze
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Re: Terrain Mesh Blending

Post by ezze » 18 Jun 2016, 15:40

... what's so jarring about the screenshot?

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Ravenwing
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Re: Terrain Mesh Blending

Post by Ravenwing » 18 Jun 2016, 17:16

You have to scroll over to the right on the screenshot to see the rocks. But see how the material of the rock and the terrain don't really look like they fit together? It just makes pretty much everything in the game world look slightly out of place. It's to Morrowind's fault, it just doesn't look very good.

Chris
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Re: Terrain Mesh Blending

Post by Chris » 19 Jun 2016, 00:16

Ace (SWE) wrote:So basically, the ground texture applies onto any geometry intersecting the ground - like a decal?
It looks like the geometry itself also connects with the intersecting object, rather than just cutting through.

This looks like a really nice idea, though I imagine more data would be required (i.e. it needs to be modded in, once the engine can do it). There's a number of models that cut into the terrain but are specifically not part of it, like buildings and stairways. So specific object instances would need to be marked to blend with the terrain. I can't help but wonder what this would mean for the terrain texture layers too, since AFAIK terrain texturing can already push the limits of the number of simultaneous textures for rendering. Having to bring in more textures or do separate passes for the blended intersections could end up being pretty costly.

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Atahualpa
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Re: Terrain Mesh Blending

Post by Atahualpa » 19 Jun 2016, 10:46

I agree with Chris and Ravenwing: We wouldn't want that kind of blending on every static. Also, like Chris stated, this process would require someone to manually (or somehow semi-automatically) modify existing data -- making it a tremendous task (although it might be feasible, if you want to build terrain from scratch, e.g. for a new game).

A quick search returned some results about that topic:

- Unity Extension: Terrain Mesh Blending
[Video] https://www.youtube.com/watch?v=pv8wjMGGGDM
[Store] https://www.assetstore.unity3d.com/en/#!/content/38742
[Discussion] http://forum.unity3d.com/threads/terrai ... is.150922/

- Vertex Blending in Unreal Engine 4
[Video] https://vimeo.com/108989270
[Discussion] http://polycount.com/discussion/comment/2169732

- other stuff
http://isiforums.net/f/showthread.php/6 ... olouration
http://www.stobierski.pl/unity/RTP.pdf
(Go to section 7, p. 63.)

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Mistahtokyo
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Re: Terrain Mesh Blending

Post by Mistahtokyo » 19 Jun 2016, 20:21

I think texture blending using some sort of decal method would would best for an automatic method. There could be some way to create exceptions so certain meshes are left out. I'm no programmer so I can't say for certain. Actual mesh blending is more of a distant dream sort of thing, since it'd be more manual and would generally be done on terrain-related meshes like rocks/etc.

Edit: Another thing that was discussed lightly a while ago that relates a bit to this is the poly count of the terrain mesh itself. Right now you need to spam meshes to create any decent amount of detail (Red Mountain overhaul mods come into mind) and the terrain experiences obvious stretching with cliffs/slopes. Could the terrain mesh not be improved, i.e. made higher-poly, then the old one subdivided with some sort of fancy algorithm to take advantage of the new poly count? Any minor clipping issues from the new positions could be addressed via .esp.

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Mistahtokyo
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Re: Terrain Mesh Blending

Post by Mistahtokyo » 23 Apr 2018, 21:55

Figured I'd resurrect this to bring it back to light and show some more recent examples:

https://www.youtube.com/watch?v=cOBApMeeJEc

https://www.youtube.com/watch?v=tyLSH5zF-rI

Regarding the issue of existing assets, can objects be assigned some sort of Blend tag that, if enabled, allows blending? Each object could then be assigned a default value of n units from the intersection of the object and terrain mesh, with the value being customizable per object to fine-tune blending amount. This way objects can be set not to blend by default unless the tag is enabled. Then one can easily go through and enable it for multiple meshes, then fine tune the intensity later. I'm no programmer, though, so it's likely this method can't work like this at all, but it would be nice if possible.

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xirsoi
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Re: Terrain Mesh Blending

Post by xirsoi » 02 May 2018, 18:44

Or, better yet, the "blend" value is an integer (still measuring "units").

< 0 = static blends into terrain
0 = no blend at all
> 0 = terrain blends into static

It could default to 0 to maintain current behavior.

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