Edit Coordinates of Surface Control Points

Hi,

I am a new user to Rhino and am trying to use it for hullform design. I have a hullform composed of surfaces that I need to alter by moving the control points to predefined locations. Is there a way to edit the position of a control point by specifying its x,y,z location?

Apologies if this is a trivial question but I have had no luck in succeeding.

Thanks

Andrea

Manually, yes… Select the point, start the Move command, select the point again as the start point and then type the destination point coordinates x,y,z at the command line. You can also just start dragging the point and while holding the point, type the x,y,z coordinates - but you need to type the coordinates with the hand not holding the mouse… There are a few other ways possible I guess, but I don’t know of one that’s much easier than the above.

A small script might make it a bit easier…

–Mitch

Also remember that surfaces, other than at the corners and a few other exceptions, do not go through control points. So if you are trying to create a surface from a table of offsets you can not just position the control points at the offset locations. A different method is needed.

Thank you for your super quick help Mitch, I’ve tried it out but I must be doing something wrong as the point is going somewhere different. This is confirmed when I use the evaluatept command. Rather than it moving with reference to the point in world coordinates, it’s moving with the cplane coordinates. Is there something else I should key in to change the reference system? I have an excel sheet that uses the PIW coordinates. Have no idea how to do script in Rhino yet but I look forward to learning in the future if this work flow works in principle.

David, yes thank you pointing this out. I’m hoping that since the changes I’m making are small, the difference between the actual surface coordinate and the control point would be constant. I did this because I couldn’t find an alternative procedure. Would you recommend something else that would give me a more defined approach? I am working of a surface model that was given to me, I would have otherwise started with sections of the hullform or a table of offsets

Once again, apologies if these are trivial questions

Your help is greatly appreciated

Andrea

Rhino interprets x,y,z typed inputs at the command line as active CPlane coordinates by default. If you want world x,y,z coordinates, type a “w” first to force Rhino to use them - i.e. “w1,2,3”

–Mitch

Hi Andrea - Setpt is what I’d use - (Transform menu > Set XYZ coordinates.)

-Pascal