Note that if you need to sample multiple things, rather than building up an uber-SampleType, you can first compute a sample with SampleType=FMeshUVSampleInfoto find the correspondence information, and then construction additional samplers of typeEMeshSurfaceSamplerQueryType::TriangleAndUV, and callCachedSampleUV(), to avoid expensive BVTree constructions and UV-to-3D recalculation.