Won't Snap to Curves


I’ve always used Rhino for Windows and now finally downloaded it for Mac. However, I cannot for the life of me get curves to snap to another curve. It stays on the grid only. I have already turned GridSnap off and on, same with Osnaps and with Ortho. I’ve restarted Rhino too. In the Osnaps panel, On Curve, On Surface, On Polysurface and On Mesh are all greyed out D: Please help?

Thanks very much!

Hello- End and Near OSnaps are probably what you’re looking for?


What command are you using to move the first curve. The OSnaps you list are only available when a command needs a location.

Thanks for your response :slight_smile:
I’ve tried both by just dragging it and with the Move tool.

Thanks for responding :slight_smile:
Both End and Near OSnaps are already turned on!

Does Rhino for Mac have a “Snap radius” setting? In Rhino for Windows it is in Options > Rhino Options > Modeling Aids.
If the snap radius is set to a very small value such as 1 or 2 pixels it can be difficult to snap to objects.


Mmm it’s at 15.

That’s the same as my setting. It may be the default.

Does the snap problem only occur when moving curves? If you use the Point command can you snap to another object to place the point?

Good point! (No pun actually intended).

Trying to set a point on a curve does work in one file but not in another, even though they both have the same Osnaps on.

Hello - are you sure they are curves in the file where it does not work? Could you be seeing the wire frame of a mesh for example?


Oh my goodness. I think you’re bloody right. I mean, it’s working now when I try it with new forms but not on where I was trying it before, which was apparently a surface. But I’ve always been able to attach it to a surface, nay?

Hi Celeste - surfaces can show wires that are part of the surface but not free curves - these are ‘isocurves’. ExtractIocurve or ExtractWireFrame will generate actual free-standing curves at these locations. Surface edges on the other hand should behave like free curves as far as snapping goes.


Thanks very much for the explanation, Pascal. But so things cannot be snapped to mere surfaces?

have you got project checked in the snap settings? if so uncheck it.

they can, but any command has to be called up prior to activate those snap settings. if you have a curve you want to attach to a specific point on a surface, select the curve then call move for example then select the point you are moving from and only then activate on surface then select the surface you want to aim at and move the object to a point on it.

if you want to start a curve on a surface i would suggest to place a point at the exact position first. for this call the command point then activate on surface then choose the surface then click anywhere on that surface.

to draw a curve exactly along a surface you get several options. one is to use InterpCrvOnSrf

Thank you so much. That was so helpful.

Thanks everyone!