Projection curve for surface trimming

[tsibbs]

I have been attempting to trim a nurbs surface using a projection curve; I am able to project the curve onto th surface, but when I attempt to trim the surface, I receive the following message in the script editor: "Warning: Trim: changed to keep originals on; curves on surface have construction history with the dependency on the surface itself. //" Any help would be greatly appreciated =)

my $.02

[nefarious]

It must be because on the Trim Settings you haven't selected "Keep Original" under the Standard Options tab and have the Construction History set to On.
Try it, it should work.
You can also do it by setting the Construction History to Off BEFORE creating your COS's, then, the trim tool should present no problem.
I'm also starting in Maya, have used it around 6 times since I got it (3 weeks ago), any other question, feel free to ask, I'm also trying to learn.
Hope it helped you.

[tsibbs]

I have tried that, but I am unable to select the nurbs surface with the trim pointer when I do. I have discovered that, since the surface I am projecting the curve onto is curved, when I angle the camera to project the curve onto two parts of the surface, I am able to trim the surface, but it trims the wrong end of the surface only (ie the one with surface normals projecting away from the original curve used for projection). What settings do I have to change in order to get the correct side of the nurbs surface trimmed?

my $.02

[nefarious]

Well, I haven't had any problems using TRIM 'til now... I usually do the COS Projection on an ortographic view (ie. side, top, front, etc...), when I use the Trim tool I firt select the NURBs surface (most of the cases a sphere with 2 COS resulting from a projection), then select the trim tool, at this point you should pay attention to what the status bar says, it provides you with information about the tool, what portion must you click, to select which part will remain and which one will be trimmed away. If you're having trouble selecting the projected COS that you want, try doing a zoom and pick the one you DON'T want (before doing any trimming), erase it or hide it and next time you pick on a COS you'll be sure that you're picking the correct one.
Hope it helps.

[pringle]

As far as I have been told by my Maya-sensei, PCOS projects two curves (or rather three) of which only one is a true NURBS-curve. So if you have a circle standing vertical in the middle of a cylinder, it will project what appears to be to curves - one on each side of the cylinder. The false projection is divided in two semi-circle parts and cannot be used as an integrated NURBS curve (or for trimming). So if you want two PCOS do it one time, select the false curves and delete them, reverse the direction of your projector curve and do it again (remember deleting the last set of false curves).
As far as the error message goes, you might have some transformations of the surface that don't go well with the projecting. Try deleting the history of the surface.

Dunno if this is any help...I'm new to it myself. And I have no explanation for the "false" curves...I was told and didn't dare ask any questions!

Best Regards

Rasmus Jensen