So lets assume I want to make a Houdini Engine procedure that works with both Unreal Engine and Unity.
As fas as I understand, I have to mark collision geometry for both engines in different ways (though I could be wrong about this). Therefore I would like to add a switch that will create different collision based on what game engine I'm running in. Obviously I could just make a manual parameter for this, but I guess there is a bit of script that will do it for the user. Any idea what such a script might look like?

Both engines should expect the same collision mesh group names so there's no need for a special switch to distinguish between them.

Both Unreal and Unity expect “collision_group” or “rendered_collision_group” primitive group name prefixes as collision meshes.

Thanks! Well, there goes my example.^^
- Still curious whether it's possible. For no practical reason right now.

It's not possible yet to tell between plugins inside your asset but we are looking at adding some kind of check in future releases.

It is still recommended that asset be made to run the same on all plugins and we do strive to achieve some level of consistency across our plugins.

But…we also know there will always be some differences.

Thanks! - Always awesome to hear from the devs!

Out of curiosity, are there any news on this?

Actually, yes! You can check the HAPI_ENV_CLIENT_NAME env var for “unity”, “unreal”, “maya”, or “c4d”. Here's an example asset.