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[.net] Consequences of making M34 negative...?

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At work, we're developing a data visualization program based on the Earth. The data comes to us in a right-handed coordinate system, and we want to display the data in our Earth scene. The decision has already been made to use Managed DirectX to build our "engine." (I use the term very loosely.) However, it's kinda tough to think about plotting data from a right-handed coordinate system inside a left-handed one (at least for me, anyway!), so we have a small predicament on our hands. One idea being researched is drawing everything using the *RH functions (half of us were OpenGL programmers..). The other is converting data to a left-handed system, then plotting it (something I'm not necessarily opposed to). So we drew the Earth using a right-handed system, set the CullMode to CW, the works. However, in doing so, we ended up making M34 in the projection matrix negative. The MDX documentation says the following: In Microsoft Direct3D, the M34 element of a projection matrix cannot be a negative number. If an application needs to use a negative value in this location, it should scale the entire projection matrix by -1 instead. We didn't see any immediate consequences to doing this, but we're trying to make sure that everything is kosher before moving in that direction. Does anyone know the consequences of this? Please note that I didn't write the code, so I might have some of the facts wrong, but the question is right, this much I am sure. If I have some info wrong, please forgive my ignorance. Thanks in advance for your help.

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having a negative M34 will break on some nvidia cards. I managed to find this out the hard way. Although usually only very old ones (geforce 2 era). The driver seems to end up treating the matrix as if it was positive anyway. So things get a bit weird.

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