Hellyo guys

I have exported my Houdini flipfluid simulation as .prt sequence thanks to the PRT ropdriver with “Normal” attribut.

When I'm loading my particles with a Prt Loader, the Particle Data Viewer see perfectly Normal attribut.

But when I'm rendering with Phong Surface + 1 light my particles are black.

I've read from Bobo about 3DSmax : “the X axis of the particle's Orientation will be used automatically” and in Houdini it seems that the +Z axis is used for normal orientation.

Do you know how to re orient my particles Normal from +Z axis to +X axis before export ?

Thank you very much if you can help me.

You should ask which particle attributes are being used for this purpose. I tried a default flip fluid from object and those particles don't have any orientation attributes at all save for “v” (velocity).

Thank you very much for your reply Edward, I understand what you mean.

The problem was in Krakatoa, so I have add a Negative node to my Normal attributs with the Magma Flow and now the rendering is correct.