Can you add a joint origin to a curved (sculpted) surface?

[banksysan]

I'm trying to add a joint origin to a sculpted surface.  I need it at a specific point, but the b-rep generated doesn't have selectable points where I want it (in this case in the centre of the flat area).

How do I control where selectable points are on my generated body?

[TrippyLighting]

Please share your model.

[banksysan]

It's just a brand new project, drawing a quad circle.

I have just worked out a possible solution though, I'll post it up.

[banksysan]

Actually, looks like I was premature in thinking I'd solved it.

[TrippyLighting]

When creating an object in Sculpt mode you always start referencing am origin plane and if the object is going to be symmetric the origin should be in the center of that symmetry.

Then you can use the origin of the component to locate your joint origin in reference to it.

This is a very good question BTW and the solution is not really very obvious.

[TrippyLighting · Accepted solution]

See screencast:

[banksysan]

I can't create one on the surface then?

When I create a body (e.g. a cylinder) in the model workspace I can put my joint origin on the end.  Is it the case that, with a sculpt, I have to create it as a component so that it has its own origin and then position joint origins at absolute positions from that origin?

That's going to get painful when dimensions change.

Perhaps I'll create a small primitive shape and join that to the sculpt and then put the joint origin on that.  (I suspect there'll be more pain going that route as well though.)

[banksysan]

OK.  I suppose it isn't actually that terrible, just some minor realigning here and there.

Thanks.

[TrippyLighting]

Sculpt models are really NURBS surfaces after you click "finish form". Fusion 360 cannot determine a snap point in the "center" of a compound curved surfaces.As such you are limited to vertices and edges.

I would not rely on the joint origin maintaining its position after changing sculpt geometry.