Mesh deform along curve

[TheDuckCow]

For various applications, it is becoming increasingly apparent that having a way to deform pre-provided meshes to follow along a curve in Godot will be incredibly helpful.

The applications of such a feature:

• Allow users to create hand crafted roads exactly matching the style and theme of their game, but still have the flexibility of defining the shape of their roads via curves (vs static lego-dropped blocks).
• Allow users to use more complex geometry to be instantiated along the edges of the road, once we also have the ability to generate curves on the outside rim of roads (for sidewalks, barriers, etc).

One person did create a C++ native project here, but has been untouched in over 4 years: https://github.com/TheFamousRat/MeshCurver/tree/master

It does seem likely that it would be a bit slow to implement in gdscript, but this could also be greatly mitigated by caching placements to meshes in pre-defined scenes (#109)

This seems like it would be useful enough it would actually warrant being its own plugin. But, we could see about implementing a lightweight version of it first here.

[TheDuckCow]

Seems that someone has made a good stride towards this! But for Godot 4, would be interesting to see if they post more about this:
https://twitter.com/KasperArnklit/status/1708824724808069506

(reddit post: https://www.reddit.com/r/godot/comments/16xvoxm/made_a_little_tool_to_make_meshes_repeat_along_a/)

[TheDuckCow]

When we get to this stage, here's a video of an equivalent road generator tool for Unreal Engine (https://www.youtube.com/watch?v=ndXxlOlRRk0) which looks pretty impressive. They essentially have stacks of arrays or rather checkbox rows which define which kind of feature to be added and arrayed along a road. Their materials are pretty impressive too. A few things that are nice about this tutorial:

• Drag and drop material replacements for arrayed elements
• Different options for how the road conforms tot he terrain including blending to below materials for things like dirt roads
• Lots of different road-side elements which each individually can have their own modifications.
• Tick boxes to simply enable common features like sidewalks, railings, gutters, etc. And a feature such that you can just visualize one or more of them, in case you don't want the base road mesh. This is interesting, as indeed you might have a custom road mesh but then want to use the other procedural elements for instance.
• Tools that actually drive input into the shape of the terrain (instead of the other way around)
• And goes without saying, PBR materials out of the box
• Impressive demo with procedural placement of things like leaves along the floor and roadside trees, part of unreals broader mechanism for procedural generation that I'm very jealous of.