CityEngine to Unreal Engine - export CE streets (lines) as UE4 editable splines

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02-07-2021 05:46 AM
Status: Open
BrianWamsley
Occasional Contributor II

I think it would be nice if we could export CE streets (lines) as UE4 editable splines.   The use case(s) for this feature would be to mix the mesh/modeling creation abilities of CityEngine with the landscape spline capabilities of UE4.    I think it could be the next step for Vitruvio of being able to generate streets in-engine.  In my limited experience with Vitruvio, what I saw was the ability to use a spline generated "fill mesh" by filling the spline circle, good for buildings, but useless for streets.   I don't see the streets codes being able to harness that but maybe someone has (I'd love to know how).  I've theorized that I could design everything to a standardized mesh size, say 32 by 32 mesh grid (more or less for desired detail) in CE, that maybe I could then use Vitruvio for streets in UE4 right now by attaching the mesh to the spline (with a blueprint that replicates it down the path) and running Vitruvio off the mesh.

The stream restoration project/model I did used  CE for modeling the stream with a UE4 spline mesh for creating the water, another use case for spline export from CE.   

The other use case idea I had in mind, I discussed using the fence code to make a monorail model in the CE board, I want to take it from CityEngine and ride the monorail in UE4,  but to do so I would need a connected spline so that I could attach the model and camera to a UE4 camera rig attached to the spline path.  If I could export a spline I could point to it and save the manual spline creation time. 

Last and least,  a lot of procedural assets in UE4 are based on the spline mesh system.  If users could take GIS data imported into CE or "get map data" to generate real world splines- that could be a powerful workflow for real-world real-time enterprise users.    

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1 Comment
BenjaminNeukom

Hi @BrianWamsley 🙂

Thanks again for your great input!

 

I think it would be nice if we could export CE streets (lines) as UE4 editable splines.   The use case(s) for this feature would be to mix the mesh/modeling creation abilities of CityEngine with the landscape spline capabilities of UE4.    I think it could be the next step for Vitruvio of being able to generate streets in-engine.  In my limited experience with Vitruvio, what I saw was the ability to use a spline generated "fill mesh" by filling the spline circle, good for buildings, but useless for streets.

One issue is that Datasmith does not support Splines right now, so getting them into Unreal requires some Python scripting on CE side and custom importers for Unreal as well. Hopefully Datasmith will support Splines in the future to make this easier. But you are completely right that it would be very convenient for normal "static" Datasmith exports as well as for Vitruvio.

 

The stream restoration project/model I did used  CE for modeling the stream with a UE4 spline mesh for creating the water, another use case for spline export from CE.   

The other use case idea I had in mind, I discussed using the fence code to make a monorail model in the CE board, I want to take it from CityEngine and ride the monorail in UE4

Sounds like great use cases! We were actually doing some testing internally as well with cars which use the spline system from Unreal to drive along streets which were exported from CityEngine.

Hopefully we can get some more work done and make that workflow available to users in the future (again would most likely require spline support for Datasmith so it can be exported easily).

 

Best,

Benjamin