Spline Decals?

[Haoris]

This topic became an interesting quest.

Yes, this picture you posted 2 years ago (****) explain why spline decals is a must have feature for a modern game engine
https://i.imgur.com/yPC873B.jpg

[Whammy]

As another user frustrated by the lack of spline decals for road and path building, I have to ask why has this not been given any attention by Unreal? Trying to integrate road/path/trail spline meshes with landscapes is extremely time consuming and difficult. The results are often disappointing with issues including z-fighting and rough edges that don't match the terrain. This needs to move up the priority list especially since this feature is already standard in other engines.

[roughdominator]

Guys I guess we may be onto something with the new RVT in 4.23. Here is a snippet from Runtime Virtual Texturing doc:

"A Runtime Virtual Texture (RVT) creates its texel data on-demand using the GPU at runtime and works similarly to traditional texture mapping. The RVT caches shading data over large areas making them a good fit for Landscape shading that uses decal-like materials and splines that are well-suited to conform to the terrain."

My simple mind cannot connect the dots exactly but maybe someone with more brain power can shed some light?!

Here is the link to the whole page:
https://docs.unrealengine.com/en-US/...ime/index.html


EDIT:
Can somebody please explain what exactly are we seeing in this video?!

https://youtu.be/HaQ2uTdH1yQ

It's here in the docs:
https://docs.unrealengine.com/en-US/...ing/index.html

[jonimake]

EDIT:
Can somebody please explain what exactly are we seeing in this video?!

https://youtu.be/HaQ2uTdH1yQ

It's here in the docs:
https://docs.unrealengine.com/en-US/...ing/index.html

It's rendering the landscape spline into the landscape virtual texture during runtime. It does it by projecting it top-down. Basically we got spline decals now.

[Haoris]

It's rendering the landscape spline into the landscape virtual texture during runtime. It does it by projecting it top-down. Basically we got spline decals now.

That's cool but does somebody knows how to do this? There's nothing in the doc except a "you can do this" but without any explanation

[Tim Hobson]

That's cool but does somebody knows how to do this? There's nothing in the doc except a "you can do this" but without any explanation

Apologies, it looks like the Quick Start Gude for Runtime VT and the settings reference page didn't publish. I'll check on this tomorrow and we can get these out to you.

RVT requires some specific setup that the doc doesn't go into super amounts of detail about.

[Haoris]

Apologies, it looks like the Quick Start Gude for Runtime VT and the settings reference page didn't publish. I'll check on this tomorrow and we can get these out to you.

RVT requires some specific setup that the doc doesn't go into super amounts of detail about.

Thanks, I tryied to recreate the material of this doc (with runtime virtual texture volume set with a runtime virtual texture asset, etc) and the result is a full black material https://docs.unrealengine.com/en-US/...ime/index.html
When switching to shader model 4 (which I guess doesn't support virtual texture) the material works, as intended by the feature switch node but as soon as I switch back to shader model 5, the material is full black.

[Tim Hobson]

Haoris

Here's a temporary link to the Runtime VIrtual Texture Quick Start guide until the page is published. This guide walks through using an existing Landscape material setup and converting it to use RVT. I specifically chose to use the simple Landscape material from Content Examples as a starting point, but if you have a properly setup landscape material that is already painted onto your terrain, you should be good to jump in and follow this guide to convert it to RVT. The "full black material" is pointed out in this guide and is part of the setup process.

[Haoris]

Haoris

Here's a temporary link to the Runtime VIrtual Texture Quick Start guide until the page is published. This guide walks through using an existing Landscape material setup and converting it to use RVT. I specifically chose to use the simple Landscape material from Content Examples as a starting point, but if you have a properly setup landscape material that is already painted onto your terrain, you should be good to jump in and follow this guide to convert it to RVT. The "full black material" is pointed out in this guide and is part of the setup process.

It works but is it possible to used a mask like decals so we can make path like this?


Also quality drop extremely low with this. I tryied increasing settings in the runtime virtual texture asset but landscape textures are still blurried like using a very low mipmap.

[Tim Hobson]

Masked, no. Just use Translucent and then drive the blending with Translucent blend mode and an alpha mask plugged into Opacity input.

There's no complex setup to achieve this. Just set up like you would any masked/translucent material except that it should use the Virtual Texture Domain.

For the quality issue, it doesn't update every frame. I've typically reset it by using simulate or PIE for a refresh. there may be another way that I'm not aware of. I've only used VT for a short time while documenting the majority of it and doing some simple set up during this time.

[Haoris]

Ok so after some tests, it looks like the quality of the virtual texture is relative to the size of the RuntimeVirtualTextureVolume which make this unusable on landscape for almost every project, even while setting the size of the virtual texture in the RVT asset to 8 (max value), unless you work on a landscape smaller than a RuntimeVirtualTextureVolume with scale of 10000*10000 max.
While using it on a 8km² lanscape it goes from this :
To this :

In fact, to get the same quality than in the first screenshot, I have to set the scale of the RuntimeVirtualTextureVolume to 5000*5000 which is not really usable

[roughdominator]

Ok so after some tests, it looks like the quality of the virtual texture is relative to the size of the RuntimeVirtualTextureVolume which make this unusable on landscape for almost every project, even while setting the size of the virtual texture in the RVT asset to 8 (max value), unless you work on a landscape smaller than a RuntimeVirtualTextureVolume with scale of 10000*10000 max.
While using it on a 8km² lanscape it goes from this :
To this :

In fact, to get the same quality than in the first screenshot, I have to set the scale of the RuntimeVirtualTextureVolume to 5000*5000 which is not really usable

So this is why they used a micro landscape in the video demonstration?

[Haoris]

So this is why they used a micro landscape in the video demonstration?

Maybe they forgot to do large scale test because a demo with landscape spline roads is obviously made with large maps in mind.

I tryied it with world composition and 25200*25200 tiles. I have to assign the runtime virtual texture asset to each landscape streaming proxy but:
- If I assign the RVT volume to the landscape component (in the persistant level) I get the same low quality than in previous screenshot
- If I assign one RVT volume per landscape streaming proxy (ie tiles) the quality is higher (not as good as original landscape material but at least usable) but only one tile look and other tiles has a lot of glitches

[BulleTime]

So just to be clear, with virtual textures its now possible to make spline decals?

[Deathrey]

So just to be clear, with virtual textures its now possible to make spline decals?

Yes, that would be so.