I'm having trouble with mantra rending hair with houdini 16 indie. I keep getting an error message.



mantra: Unable to resolve geometry op:/obj/geo1_deform/OUT_GROOM.
Please ensure the object is included for rendering.
You can turn off vm_renderable if needed.
Invalid detail specified
Invalid detail specified
Invalid detail specified

I don't know how to turn off vm_renderable or what is causing mantra to fail here. Is this a bug?



any help much appreciated



N

Does it work if you do something simple?

eg.
- brand new scene
- add sphere
- add fur
- render

Moin,

the problem is, as far as my research has gone, the misleading documentation:

One of the groom objects has to actually be set to “visible”, as it has to get evaluated. The setup you need for a deformed hair is, if using the shelf tools:

- original groom object, which defines the geometry and skin to be used (this one does not have a “display flag” set, which is what documentation refers to, by setting this to invisible you avoid seeing the groom hair)
- the deformer object, which takes the original groom object and applies deformation to it, passing it to the hairgen (this one NEEDS to be set to visible, which is the bit that the documentation leaves unclear, this does not have any “groom hair” itself, so it can and must be visible)
- the hairgen object (which takes the deformer object and creates the actual render hair), this, obviously, is only set to visible when you want to render the hair.

Also note (this is not related to your error message) that the original geometry has to be at rest state, while the deforming geometry (the “skin”) is getting deformed. If you don't want to use two instances of geometry, you can link the “rest state” geometry to your geometry node BEFORE the deformer gets applied and the “skin” link to the deformer node. That works perfectly.

I hope this helps.

Marc

I recorded a quicktip about this, I hope this is of somehelp:



Marc