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Be carefull with "normalize"



Be aware that if you use the "normalize" function from wm3, it might give the result (0,0,0) if the norm of the vector is smaller than a "tolerance" value. It sounds very strange to me, as I see no reason for this check, and I was wondering if it could not cause problems in some cases, when a "normalized" vector has length 0... Janek had this problem when defining the normal of some triangular facets (of small size) by normalizing the cross product of edges vectors. I prefer not to be the only one thinking about this potential problem, which probably needs a fix.

A few ideas from a discussion with Janek :
1- possibly fix minWm3 so that the test vs. tolerance is removed
2- display a warning to the user when the tolerance is hit and the vector is "rounded" to (0,0,0)
3-  run batch tests with/without the tolerance test



Chareyre Bruno
Maitre de conference

Grenoble INP
Laboratoire 3SR - bureau E145
BP 53 - 38041, Grenoble cedex 9 - France
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