Stitching together meshes, issues with Cloth.

Development Rendering
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1

Hi,

In our game, we have different uniforms per character and we can add any type of shoes to the character. To make sure that they are synchronized visually, we merge the 2 skins (shoes and body) together at runtime using USkeletalMergingLibrary. The cloth simulation works great without the merge but if I tried to merge the shoes with the rest of the body, then the cloth simulation stops working (it looks like before without cloth). I have added the same cloth asset in the shoes but it didn’t make a difference. Is it possible to merge 2 skeletal meshes with cloth? If yes, then what am I doing wrong (see the code below)? Thanks.

Laurent

`void CopyClothFromMesh(USkeletalMesh* sourceMesh, USkeletalMesh* targetMesh)
{
if (!IsValid(sourceMesh) || !IsValid(targetMesh))
return;

// Iterate over clothing assets in the source mesh.
for (UClothingAssetBase* clothingAsset : sourceMesh->GetMeshClothingAssets())
{
if (!IsValid(clothingAsset))
continue;

// Duplicate the clothing asset.
UClothingAssetBase* duplicatedAsset = DuplicateObject(clothingAsset, targetMesh);

if (IsValid(duplicatedAsset))
{
// Add to target mesh
targetMesh->AddClothingAsset(duplicatedAsset);
}
}
}

// Do the merge of shoes and body.
FSkeletalMeshMergeParams mergeParams;

mergeParams.MeshesToMerge.Add(characterMesh);
mergeParams.MeshesToMerge.Add(MotionGroupAsset->Shoes);

mergeParams.Skeleton = characterMesh->GetSkeleton();
mergeParams.StripTopLODS = 0;
mergeParams.bNeedsCpuAccess = true;
mergeParams.bSkeletonBefore = true;

USkeletalMesh* mergedMesh = USkeletalMergingLibrary::MergeMeshes(mergeParams);

UPhysicsAsset* physicsAsset = characterMesh->GetPhysicsAsset();
mergedMesh->SetPhysicsAsset(physicsAsset);

// Copy the clothes.
CopyClothFromMesh(characterMesh, mergedMesh);

// Set the final mesh.
MeshComponent->SetSkeletalMesh( mergedMesh );
MeshComponent->bDisableClothSimulation = false;
MeshComponent->ClothTickFunction.bCanEverTick = true;`

2

Hi,

Any update?

Thanks.

3

You will have to call BindToSkeletalMesh() and probably set the section data, since otherwise your SkeletalMesh won’t know about the clothing asset it’s using, and it will just add a ClothingAsset to the list but not use it.

Here’s how it’s done in the SkeletalMesh editor:

`if (UClothingAssetCommon* ClothingAsset = Cast(InNewEntry->Asset.Get()))
{
ClothingAsset->Modify();

// Look for a currently bound asset an unbind it if necessary first
if (UClothingAssetBase* CurrentAsset = Mesh->GetSectionClothingAsset(InLodIdx, InSectionIdx))
{
CurrentAsset->Modify();
CurrentAsset->UnbindFromSkeletalMesh(Mesh, InLodIdx);
ClearOriginalSectionUserData();
}

if (!ClothingAsset->BindToSkeletalMesh(Mesh, InLodIdx, InSectionIdx, InNewEntry->AssetLodIndex))
{
// We failed to bind the clothing asset, reset box selection to “None”
SClothComboBoxPtr BoxPtr = ClothComboBoxes[BoxIndex];
if (BoxPtr.IsValid())
{
BoxPtr->SetSelectedItem(ClothingNoneEntry);
}
}
else
{
//Successful bind so set the SectionUserData
int32 AssetIndex = INDEX_NONE;
check(Mesh->GetMeshClothingAssets().Find(ClothingAsset, AssetIndex));
OriginalSectionData.CorrespondClothAssetIndex = static_cast(AssetIndex);
OriginalSectionData.ClothingData.AssetGuid = ClothingAsset->GetAssetGuid();
OriginalSectionData.ClothingData.AssetLodIndex = InNewEntry->AssetLodIndex;
}
}`

4

Passed the info along.

Thank you.