I made a simple box in 3Dstudio max and exported it with KW X-port plugin in .X format. Now I'm loading this mesh in my Direct3D project and calculating the bounding sphere of it like this:


m = Mesh.FromFile(My.Application.Info.DirectoryPath & "\Data\Models\Box.X", MeshFlags.Managed, DEV)
Using vb As VertexBuffer = m.VertexBuffer
Dim vertexData As GraphicsStream = vb.Lock(0, 0, LockFlags.None)
objectRadius = Geometry.ComputeBoundingSphere(vertexData, m.NumberVertices, m.VertexFormat, objectCenter)
vb.Unlock()
End Using


Now the problem is that I'm getting some weird results as center and radius:


objectCenter.X : -944.5798
objectCenter.Y : 0
objectCenter.Z : 944.5798
objectRadius : 0.007336923


although box's width, height and length are about 50, and box's position is 0. What could be going wrong here?

The 3rd parameter should probably be the vertex stride, not the vertex format. I'm not sure how to get that in VB, but in C++ you'd call ID3DXBaseMesh::GetNumBytesPerVertex().

In Managed Direct3D there are 4 options to use this function. One of them is the one that I wrote above. When I changed it to what you said, like this:

objectRadius = Geometry.ComputeBoundingSphere(vertexData, m.NumberVertices, m.NumberBytesPerVertex, objectCenter)

everything worked great.
BUT, I found that only the meshes that are exported with KW X-port plugin from 3Ds max have this problem. PandaExporter plugin seems to work well with this but unfortunately it doesn't export tangets, so I can't use it.
Thanks for the help.