Runtime Mesh Component

[FishOrBear]

There's clearly a shading issue with RMC on 4.20 right now. Comparison with ProceduralMeshComponent :

Is there any difference between using PMC and RMC now?

[Chumble]

Is there any way (in blueprint) to obtain vertex data for a given mesh section index? I want to use Update Mesh Section to update a vertex relative to its current position. So far I've been keeping all this data in a separate array of vertices but if I could simply grab it from the section it would simplify things.

[LordNelson7]

This one doesn't work for some reason: https://github.com/stefanseibert/RuntimeMeshComponent

Build it with this one, this WORKS with 4.23.1: https://github.com/Koderz/RuntimeMes...ent/tree/v4dev

I made the same mistake until I found Version 4(the second link) the older one won't compile for me for some reason, I found a link to Version 4 on the Discord for RMC.

https://discord.gg/KGvBBTv

[CharonLabs]

Has anyone successfully built the plugin for 4.23.1 ? I tried it with the sources from https://github.com/stefanseibert/RuntimeMeshComponent but get an error when i use it as an engine plugin.

[Mctittles]

Is there a way to get the vertex positions in world coordinates? Say I have a runtime mesh that has been moved and rotated and I would like to get the vertex positions so I can combine it with another mesh but keep it's location.

Ok I figured it out. Send the actor you want to merge with the transform of the actor you want to merge from. Loop through vertices and use TransformPosition on each one:

for (int32 vertCounter = 0; vertCounter < verticesSent.Num(); vertCounter++) {
                const FVector WorldSpaceVertexLocation = transformSent.TransformPosition(verticesSent[vertCounter].Position);
                vertices.Add(transformSent.TransformPosition(verticesSent[vertCounter].Position)-GetActorLocation());
            }

You might also need to subtract your current actors location (or the difference between the two actors). In my case "-GetActorLocation()".

[Mctittles]

Is there a way to get the vertex positions in world coordinates? Say I have a runtime mesh that has been moved and rotated and I would like to get the vertex positions so I can combine it with another mesh but keep it's location.

[edstoica]

I'm still wondering what the sections with DualBuffer are. Anybody any idea?

    template<typename VertexType0, typename VertexType1, typename IndexType>
    FORCEINLINE void CreateMeshSectionDualBuffer(int32 SectionIndex, TArray<VertexType0>& InVertices0, TArray<VertexType1>& InVertices1, TArray<IndexType>& InTriangles, bool bCreateCollision = false,
        EUpdateFrequency UpdateFrequency = EUpdateFrequency::Average, ESectionUpdateFlags UpdateFlags = ESectionUpdateFlags::None)

[Rumbleball]

Does it make a different in performance how many "sections" you have as long as you use the same material for all of it? Doing one mesh for discrete items and just easier splitting them into sections.

Also how does the UV maps work when you define them for each section? Does the plugin piece them altogether into one?

Each section is a different material. Each material is a Draw-Call. With 4.23 Unreal changed the rendering by batching together same things. Dunno exactly what that means and how that applies to the RMC.

As each section has its own material UV is not connected. Each section can be 0..1 without problems. You can also exceed 0..1 range for UV in Unreal.

[Mctittles]

Does it make a different in performance how many "sections" you have as long as you use the same material for all of it? Doing one mesh for discrete items and just easier splitting them into sections.

Also how does the UV maps work when you define them for each section? Does the plugin piece them altogether into one?

[Mctittles]

Oh spoke too soon. Guess I didn't know what FaceIndex was well enough. "The FaceIndex is only set when using a triangle mesh for the query.".


So is there a way to get which section was hit with a line trace?

[Mctittles]

So I'm trying to get the section where a trace hit and having problems. I noticed there is "GetSectionIdFromCollisionFaceIndex" in the mesh component, the issue I'm having is the hit returned from World->LineTraceSingleByChannel always has FaceIndex -1.

[HOUmmel]

SetMeshCollisionSection or something like that.

Thanks, i will check it out

[Rumbleball]

Hello,
is it possible to add Collision to a MeshSection which use a different VertexBuffer?
I have 2 VertexBuffers the first is for visuals and the 2nd for Collision only, so it does not need to be drawn or need Normals and Stuff.
At the Moment i create a 2nd MeshSection with that 2nd Buffer and set it to invisible. But maybe that is slower...

SetMeshCollisionSection or something like that.

[HOUmmel]

Hello,
is it possible to add Collision to a MeshSection which use a different VertexBuffer?
I have 2 VertexBuffers the first is for visuals and the 2nd for Collision only, so it does not need to be drawn or need Normals and Stuff.
At the Moment i create a 2nd MeshSection with that 2nd Buffer and set it to invisible. But maybe that is slower...

[Rumbleball]

Since UE4.20 they've added the ability to apply a render target to the landscape as displacement.. without the runtime functionality. How feasible would it be with the RMC?

Take a texture (RenderTarget is a texture), create a plane with subdivisions, read the pixel and displace the vertex Z position depending on the color value, update the vertices to the RMC. Its a bit of coding but not that problematic if you only want a texture that maps to a fixed size plane. Needs C++ tough.