SU4 beta: Fallbacks for custom biomes not working anymore

[Sasa]

Version: 1.6.7.0

Frequency: Consistently

Severity: Blocker

Marketplace package name: Jurassic World: Archipelago

Bug description:

Above product heavily relies in biome fallbacks to be working properly so there is a proper mix between various grass types - without having to place performance heavy polygons for each patch of grass. See the following snippet from the individual biomes.xml (bottom of the file) we set up:

<BiomeRule name="JW_Fallback">
	<TreeSpecies spawnPerHectare="1" artificialSurfacesScaleFactor="1.0">
		<TreeSpecie name="InvisibleScrub" spawnRatioMin="1.0" spawnRatioMax="1.0"/>
	</TreeSpecies>
	<PlantTypes>
		<PlantType name="PLANTS_MEADOW_Savanna" surfaceType="ML_LOW_VEGETATION"/>
		<PlantType name="PLANTS_WATER_Temperate" surfaceType="ML_DIRT_AND_MUD"/>
		<PlantType name="PLANTS_MEADOW_Tropical" surfaceType="ML_SAND" />
	</PlantTypes>
	<GrassTypes>
		<GrassType name="GRASS_WATER_Temperate" surfaceType="ML_DIRT_AND_MUD" useColorMask="false" />
		<GrassType name="GRASS_MEADOW_Savanna" surfaceType="ML_LOW_VEGETATION" />
		<GrassType name="GRASS_Cities" surfaceType="ML_ROCK_SURFACE" />
		<GrassType name="GRASS_Cities" surfaceType="ML_ASPHALT" />
		<GrassType name="GRASS_MEADOW_Tropical" surfaceType="ML_SAND" />
	</GrassTypes>
</BiomeRule>

For surface type ML_SAND this brought in some nice grass variation in SU3:

Now the same spot looks like this in SU4:

Only the surface types to the left and right (ML_LOW_VEGETATION) still show grass.

It now seems to be the case that not the packages individual biome fallbacks are used anymore, but the engine is falling back all the way to the default biomes again, making individual biomes impossible.
This is a huge issue to us as it affects all islands, not only small spots.

Repro steps: Check out area between taxiways at JWN1. Everything that’s surface type ML_SAND doesn’t display grass anymore.

[Sasa]

Package that shows the issue has been uploaded in private content.

[Boris]

Hello,

In SU4 we modified the behavior to enable more support for third parties biomes.
That means that in SU4, you now need to check “Is Default” in the biome editor to have the expected behavior.
The last read biome with this parameter will be the biome fallback.

Let me know if it’s working with the “is default” parameter.

Regards,
Boris

[Sasa]

Wow, that’s a very good improvement as previously it was not entirely clear what is being used as fallback except through experiments. Adding this tag indeed solved the issue, thank you!

Only small issue I found is that the DevMode GUI doesn’t yet reflect the change. No matter if it’s being reloaded or not:

I assume the name mentioned here should be the one that’s the actual fallback of the project, in this instance “JW_Fallback”.

[Boris]

@Sasa

Only small issue I found is that the DevMode GUI doesn’t yet reflect the change. No matter if it’s being reloaded or not:

You’re right, the UI string only refreshes after a “Build All”, a “Reload” in the Biome Editor, or when “Auto Reload” is enabled. It should also refresh on “Save”. I’ve logged an issue for this and added the bug_logged tag to the topic.

Regards,
Boris

[Melvin]

Just to be extra clear, using the default parameter is not the recommended way to do local biome overrides because it can have unwanted side effects. If you define your biome as default, people that own your package will see the effect of your biome on any place that uses the default biome, so they might have unexpected grass on sand soil for example.

The recommended way is to define a biome without any eco region (just like you did) and isDefault left unchecked, and then use polygons to apply that biome locally where you want it to be. That way you can more easily control the vegetation in your scene and make sure it doesn’t have any side effect anywhere else in the world.

Also, you mentioned that polygons are “performance heavy”, we don’t observe the same impact on our side, if that is indeed the case for you please share with us any data regarding this so we can investigate on our end.

Regards,
Melvin

[Sasa]

Thank you for the detailed input @Melvin !
We’re talking about a whole set of large islands here (see product mentioned above). Since we won’t have access to vegetation masking through the SDK there are huge amounts of polygons needed for the forests already. We simplified those as much as possible. But believe me - they do have an impact once we’re talking about larger numbers (for Isla Nublar alone there are 383k vertices for vegetation polys - after simplifying them to simple shapes and a bare minimum).
So adding polygons just to have a close to similar variation in grass types as the default scenery is not a viable option here. Particularly with xbox in mind here.

Is was working great in SU3. It’s still working in SU4 with the isDefault=TRUE parameter and doesn’t seem to have any global impact.

Checking Costa Rica beaches with surface type ML_SAND with new biome active: No grass, so at the moment the package doesn’t seem to impact default scenery, which would be highly preferred for the future. This follows the same logic as previously in SU3 with the difference that the isDefault tag has been added:

Examples of variations in grass in our package:

[Melvin]

Ok, I did not expect that many vertices indeed, that can explain the performance impact for sure. Then I guess this is fine if that works for you as it is with the new isDefault option.

The place that you are showing has an eco region set (Southern mesoamerican pacific mangroves) so it won’t use the default biome so that’s why you don’t see the impact of your biome here, but it may happen at other places.
This is acceptable, as not many areas are without eco region, nonetheless I would advise you to include a notice in your package description to ensure people using it are aware of such potential side-effects.

Please also note that, if there is another package that defines a biome as the default biome and that package is mounted after yours, it will replace your default biome and thus may break your vegetation setup.

Have a nice day
Melvin

[Sasa]

Thank you for the explanation!

So, in summary this would mean the following?

No ecoregion defined in custom biomes xml:
= Applies only for areas that have no ecoregion

isDefault with no ecoregion defined in custom biomes xml:
= Applies only for areas that have no ecoregion, but still gets overwritten if a higher priority custom biomes.xml contains “isDefault”? Even if that one has the “isDefault” only defined for a specific ecoregion?

I assume it’s not possible anymore in MSFS2024 to set up new ecoregions? I recall this was possible in MSFS2020 with GIS data / shapefiles but I couldn’t get this to work in MSFS2024.