Some objects are not rendered in UV pass

I created the sea and floating object - the ship’s hull. The ship floats in the sea, using the method from this tutorial - (dinamic paint).

Then I modeled the mast with sails, flags and ropes in another scene, and also modeled there a new hull, slightly modified, but almost the same.

I had to attach the structure (the mast, etc.) to the floating object (old hull of the ship), so that the structure repeats it movement.

I used parenting.

I transferred this structure with the mast and etc. to the first scene and parent it to the old hull of the ship. Then I moved it so that the new ship hull was in the same place that the old hull. Then I made the old hull invisible.

Then I noticed that the sail is shifting towards during the animation, so I delete the old Parenting of the sail and Parent sail to the mast.

Everything was ok.

But when I export MultiLayer EXR, in UV pass the ship’s hull and sail are black, looks like they are not used in the creation of UV pass.

Why is this happening and how to fix it?
Thanks in advance!

Possibly stupid, but do the hull and the sails have any UVs? The UV pass is the just the UV coordinates on the point of the surface, so if an object doesn’t have a UV map you’ll get nothing.

Yes you are right! I just had to unwrap them. Thank you! :slight_smile: