Spline Decals?


I’m rewrote the OP to reflect what this thread has been through. 5.9.2017

How many people need Spline Decals?
Almost everyone. It’s the most wanted feature by the UE4 community. Check out the link below!

Why people need spline decals:
It saves everyone tremendous amount of manual work and tweaking, it can also be used for many different purposes. We’ve also done a comparison between Spline Decals and the current Landscape Spline Tool.

Example of Spline Decal in Cryengine: And documentation

What features would it benefit from:
1. Blocking Grass Tool from distributing meshes within the spline width.
**2. **Remove painted foliage that are within the spline width.
3. Displacement. With spline decals supporting displacement mapping (overriding landscape’s displacement map) we can make non-destructive changes to landscape if/when landscape uses tessellation and displacement mapping. If displacement mapping on spline decals come true, it opens the doors for many more uses on landscape besides projecting a material on a surface. (This is more important than the other 2). Spline Displacement should support collision (or better say landscape collision should update to cover the deformation caused by spline displacement) otherwise we’d go through the raised/lowered areas.

Thanks! :slight_smile:


where is the original news ?
and btw +10000 for this feature .

I’d love spline decals as well.

It was on the road map ages ago, on the backlog. I can’t find it now…

Ok I second the question then :slight_smile:

Mesh decals work with the spline the SplineMeshComponent.

But mesh decals don’t “project” flatly onto a surface the way normal decals do, so decal splines would still fill a purpose that is missing currently. I desperately want spline decals as well.

Any Epic words on this massively important feature request?

Agreed, the lack of spline decals in UE4 is beyond frustrating, notably for creation of roads & paths. The current spline mesh system is great for procedural walls and such but it is an inefficient solution for roads because of the gridded terrain/landscape system. Cryengine and even Torque3D have had this feature for years now so I do not understand why it is such a low priority with this engine. Every time this subject is brought up in a new thread on these boards, there is absolutely zero feedback from an Epic representative, which is depressing:(.

Did anyone from Epic have a look at this thread?

Bump, this is a feature I really want. There’s currently no viable way to achieve this as far as I know

It’d be super awesome to get this feature but I know it won’t be easy. I know someone that tried to modify the engine for this and well, the problem was non-trivial beyond all expectations

How many people should cast their voice as interested in a feature in order for Epic to implement it? or there are other factors i.e the requested feature should align with what Epic is working on? Because there is an ocean of feature requests that are never answered, regardless of how useful they are and I’m not sure if we should continue expressing the necessity of a requested feature, i.e spline decal. :confused:

sadly it’s been years that their own goals and interests seem to be the main driving factor of their focus, and not so much will to create a good, robust and complete (ie. features A, B and C working together) multi-purpose engine anymore
Usually there’s the needs of their main game project (i.e. the numerous improvements and optimizations made as Paragon needed them), some part of “keeping up with the latest and greatest” (i.e. all the focus on VR including the full editor VR mode and forward rendering only justified by VR), and then the more sporadic focus on “some feature to showcase” which happens at specific timelines (i.e. open world features developed for the Kite Demo for GDC 2015, Vulkan for mobile for the Protostar demo running on a samsung phone at the MWC 2016) after which said features seem to go back to a state of minimal maintenance

Isn’t this something that can already be done with Mesh Decals that was added in 4.11?


This is using just the BP_Spline asset form Content Examples and duplicating the mesh. One is the original base, the second is using DBuffer Decal with a simple brick material with a mask of the UE4 logo. These materials can even work with Landscape Splines.

how would you use that to project into a landscape though? without using a landscape spline to flatten the landscape, that is. just respecting the topology.

also mesh decals cause some bad artifacts at great view distances, since based on distance they push themselves towards the camera to avoid z-fighting. yes I’ve seen the code, it’s MeshDecals.usf line 104 (on UE4 4.15), which is this:

this results in mesh decals ending up wrongly being drawn on top of more and more stuff, the more you zoom out

[MENTION=4894]Tim Hobson[/MENTION], Spline decals are intended to “project” a material on the surface. Without projection it’s only like a masked mesh overlayed on other surface with lots of clipping specially on the landscape surface.

Hey guys. Woud love an update on this. Our game needs good roads. :frowning:

A ticket has been in for a while. It’s backlogged and marked as minor at the moment. This could change in the future, but if the feature is direly important to your project you may want to implement it yourself or hire a programmer to do so. There is also no guarantee that any feature request in our system will be implemented. That’s the unfortunate reality of things. :confused:

It would improve working with landscape quite a bit tbh, shame that’s it’s not a priority for you :\