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DirectX bounding sphere weird results

Started by Zosimas Feb 3, 2012 at 12:52 PM 1 reply 1.5k views

Original Post

Feb 3, 2012 at 12:52 PM

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?

Evil Steve

382

Evil Steve

Feb 3, 2012 at 1:44 PM

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().

Zosimas

Author

Zosimas

Feb 3, 2012 at 1:58 PM

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.

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