Howdy,

I'm working on some procedural fluid stuff, and need to be able to do some calculations on matrix fields in DOPs. But it seems that the GAS Field VOP doesn't support them. Is that a bug?

I've attached a small example. Basically it uses the Gas Analysis DOP to take the jacobian of the velocity, then uses a Gas Field VOP to put the determinant of the jacobian into density (just as a test of course). The Matrix Field visualization shows the Gas Analysis node is working, but a printf on the “jacobian” parameter in the Field VOP shows it to always be all zeros, which is strange, since it's default parameter value is the identity matrix. It's like Houdini is trying to set the parameter to the field, but setting all zero's instead of the actual values.

Or is there something I'm missing here?

Thanks

Although we answered you through Support@SideFX.com, I though that other users should know that the bug where matrix fields weren't properly being passed to VEX is fixed in build 9.5.360.

Also note that the det of a jacobian of a 2d vel field will always be zero because the 3rd row/column of the jacobian is 0 since the velocity is all 2d.