Create a basic mesh in Unreal 5.3

[redsigma]

It seems some of the RHI commands got changed and now the plugin throws a lot of compile errors.

Will this plugin be updated for Unreal 5.3.2 ?

[FynniX]

I use the plugin in unreal 5.3.2 without any issues

[Distantz]

using it as well for 5.3.2 without issue.

[Koderz]

Hey @redsigma What errors are you getting? This definitely works for 5.0.0 - 5.3.2, and it's working locally for me for 5.4 (Current master)

Are you trying to use the last release, or master?

[redsigma]

@Koderz I am sorry, I havent updated to 5.1 release version. I was still using the 5.0.5 version of this plugin.

I can confirm the plugin compiles properly now with the 5.1 release

---

However now that I updated, it broke a section of my code and I am not sure how I can replace it because the official documentation from the below site seems to point to missing functions https://runtimemesh.koderz.io/usage.html

The functions are CreateMeshSection and UpdateSectionMesh which seem to not be available anymore.

I checked this file as it mentions some redirectors for the CreateMeshSection but that function doesnt seem to be available either https://github.com/TriAxis-Games/RealtimeMeshComponent/blob/v5.1.0/Config/DefaultRealtimeMeshComponent.ini

Below is the code that I was using with version 5.0.5 and it was working.

            FRealtimeMeshSimpleMeshData MeshSimpleData;
            MeshSimpleData.Triangles = MeshData.RawTriangles;
            MeshSimpleData.Positions = MeshData.RawVertices;
            MeshSimpleData.Normals = MeshData.RawNormals;
            MeshSimpleData.Tangents = MeshData.RawTangents;
            MeshSimpleData.UV0 = MeshData.RawChannelUV0;

            const auto& MeshPart = NewObject<URealtimeMeshSimple>(ActorOwner);

            constexpr auto ShouldCreateCollision = false;
            FRealtimeMeshSectionKey StaticSectionKey = MeshPart->CreateMeshSection(
                0,
                FRealtimeMeshSectionConfig(ERealtimeMeshSectionDrawType::Static, 0),
                MeshSimpleData,
                ShouldCreateCollision
            );

            MeshPart->UpdateSectionMesh(StaticSectionKey, MeshSimpleData);

I looked a bit in the code and there is a function called CreateSectionGroupFromSimple which seems to have a similar signature like CreateMeshSection but it uses a FRealtimeMeshStreamRange instead of the FRealtimeMeshSimpleMeshData that is shown on the website documentation.

Could you give me an example on how to use the URealtimeMeshSimple ? Or at least if you can point me to the commit that made these functions changes.

[FynniX]

@Koderz I am sorry, I havent updated to 5.1 release version. I was still using the 5.0.5 version of this plugin.

I can confirm the plugin compiles properly now with the 5.1 release

However now that I updated, it broke a section of my code and I am not sure how I can replace it because the official documentation from the below site seems to point to missing functions https://runtimemesh.koderz.io/usage.html

The functions are CreateMeshSection and UpdateSectionMesh which seem to not be available anymore.

I checked this file as it mentions some redirectors for the CreateMeshSection but that function doesnt seem to be available either https://github.com/TriAxis-Games/RealtimeMeshComponent/blob/v5.1.0/Config/DefaultRealtimeMeshComponent.ini

Below is the code that I was using with version 5.0.5 and it was working.

            FRealtimeMeshSimpleMeshData MeshSimpleData;
            MeshSimpleData.Triangles = MeshData.RawTriangles;
            MeshSimpleData.Positions = MeshData.RawVertices;
            MeshSimpleData.Normals = MeshData.RawNormals;
            MeshSimpleData.Tangents = MeshData.RawTangents;
            MeshSimpleData.UV0 = MeshData.RawChannelUV0;

            const auto& MeshPart = NewObject<URealtimeMeshSimple>(ActorOwner);

            constexpr auto ShouldCreateCollision = false;
            FRealtimeMeshSectionKey StaticSectionKey = MeshPart->CreateMeshSection(
                0,
                FRealtimeMeshSectionConfig(ERealtimeMeshSectionDrawType::Static, 0),
                MeshSimpleData,
                ShouldCreateCollision
            );

            MeshPart->UpdateSectionMesh(StaticSectionKey, MeshSimpleData);

I looked a bit in the code and there is a function called CreateSectionGroupFromSimple which seems to have a similar signature like CreateMeshSection but it uses a FRealtimeMeshStreamRange instead of the FRealtimeMeshSimpleMeshData that is shown on the website documentation.

Could you give me an example on how to use the URealtimeMeshSimple ? Or at least if you can point me to the commit that made these functions changes.

Look into "YourProject\Plugins\RealtimeMeshComponent\Source\RealtimeMeshTests\Private\FunctionalTests\RealtimeMeshBasicUsageActor.cpp" for a example how this component works. Also took me few days to find out that there is a example.

[redsigma]

Thank you @FynniX . I kinda got something to work but it's not fully functional. I'll close this issue and come back with a reply after I found a working alternative.

[redsigma]

Also changed the title so it's more precise to the issue I have.

[redsigma]

UPDATE:

This is the new version that is working but there is a big caveat that it crashes the game sometimes. I Posted at the bottom more context

 for (const auto& MeshData : MeshParts)
        {
            FRealtimeMeshSimpleMeshData MeshSimpleData;
            MeshSimpleData.Triangles = MeshData.RawTriangles;
            MeshSimpleData.Positions = MeshData.RawVertices;
            MeshSimpleData.Normals = MeshData.RawNormals;
            MeshSimpleData.Tangents = MeshData.RawTangents;
            MeshSimpleData.UV0 = MeshData.RawChannelUV0;

            const auto& NumIndices = MeshData.RawIndices.Num();
            const auto& NumVertices = MeshData.RawVertices.Num();

            const auto& MeshPart = NewObject<URealtimeMeshSimple>(ActorOwner);

            FRealtimeMeshSectionGroupKey GroupKey = FRealtimeMeshSectionGroupKey::CreateUnique(0);
            MeshPart->CreateSectionGroup(GroupKey, MeshSimpleData);

            FRealtimeMeshSectionKey SectionGroup = FRealtimeMeshSectionKey::CreateUnique(GroupKey);
            MeshPart->CreateSection(
                SectionGroup,
                FRealtimeMeshSectionConfig(ERealtimeMeshSectionDrawType::Static, 0),
                FRealtimeMeshStreamRange(0, NumVertices, 0, NumIndices),
                false
            );
            const auto& MeshComponent = NewObject<URealtimeMeshComponent>(ActorOwner);
            MeshComponent->SetRelativeTransform(MeshTransform);
            MeshComponent->SetRealtimeMesh(MeshPart);
            MeshComponent->AttachToComponent(CustomParentAttachment, FAttachmentTransformRules::KeepRelativeTransform);
            MeshComponent->RegisterComponent();

---

The caveat is that this plugin (at least from what I have checked), doesnt seem to be safe to create URealtimeMeshSimple meshes in a for loop, for example if you plan to use it for importing a lot of parts that form a bigger mesh.

I posted the image to the crash below and it happens when calling NewObject<URealtimeMeshSimple>(ActorOwner); All the code from above is called only in the GameThread.

@Koderz Could you tell me if my assumptions above are true or is there a way to explicitly handle that locking ? Or maybe is there a way to avoid that crash from happening ?

[Koderz]

Hey @redsigma ,

This should have been fixed for a little while now, there was an issue with the internal locking mechanisms that could end up using too much thread local storage.

-Chris