Hello Teem users,

I have a question about the usage of **tenInterpDistanceTwo_d** function.

**tenInterpDistanceTwo_d** can give me a value very close to 0.

*tensors of comparable size*".

I want to calculate the orientation distance between two tensors.

Tensor A = [4, 0, 0, 4, 0, 4] i.e., perfect sphere.

Tensor B = [10, 0, 0, 1, 0, 1] i.e., linear shape tensor.

My expectation is that if a tensor is compared with a sphere tensor, the orientation should be 0.

But if I change B to [1, 0, 0, 10, 0, 1] or [1, 0, 0, 1, 0, 10], the function returns a very large orientation distance value. But B is still a linear shaped tensor. This is not what I expect.

What is the reason behind this?

Furthermore, in the paper *Geodesic-Loxodromes for Diﬀusion Tensor Interpolation and Diﬀerence Measurement*, page 6, it says '*'there is little orientation change between isotropic and anisotropic*

In this case, B is very anisotropic tensor and A is a perfect isotropic tensor and both have exactly the same trace (=12, i.e., the size in the context), why it returns a large value far from 0.

Thank you very much.

Changgong Zhang

Ph.D candidate in Computer Graphics and Visualization section

TU Delft