Don't know if this is a bug, but when I use Polywire on hairs strands in Houdini and render in Mantra or Redshift I get this "sphere" added to the geometry ( bottom image ). But what I'm looking for is the same as what I see in the viewport ( top image ).

Someone from Redshift support already looked into this, but did not have a clue.

Anyone ?

Thanks.

I put the scene in Dropbox : https://www.dropbox.com/s/4o312k663bkpiqw/Polywire_HairBug_02.zip?dl=0 [www.dropbox.com]

Houdini 19.5.493

it's because Guide Groom seems to pass packed groom (which contains the skin geo) as an output during rendering (as per internal Render flag)
I don't know if this is intentional or if it's always been this way but a quick fix in you case may be

in your /obj/polywire_hair/object_merge1
type this in Object1: /obj/sphere_object1_groom/DISPLAY
instead of just /obj/sphere_object1_groom

that will force it to always bring in the geometry node named DISPLAY with is the one that currently has display flag on, that you have been seeing and working with and it will not be switched to render flag geo during rendering which hass been the case so far

Great, thanks, that seems to do the trick.

Let's hope it's not by design, would be a bit weird if one had to use a "hack" like this to get basic stuff like this working.

But I'll report it.

Just in case someone else runs into this.

It actually is by design, if you don't force Houdini to use the "DISPLAY" output it will choose "RENDER" output by default.