# Adjusting curves in a 3D space ..tricky ! ..any tutorials on best practice?

Hi
V5

This is something all 3d modellers are going to face and have fun and games with !

If I am in ortho front view and draw a curve alongside the one I feel is a bit wriggly, I then look at the result in Left view and see it kicking out somewhat. So I adjust it there and notice its spoiling the shape I had in front view, then try further and improve things only maybe to discover that its not so clever in top view now !

As its a curve, and a very shallow one at that, curving out along its 125mm length by 1mm or so, not quite planar, I need to be viewing it sort of side on I guess.

I need to constrain its adjustment and movements to a planar ‘sheet’ best fitting its shape. There will also be curves in my job that wont have a planar aspect though.

There has to be best practice for working on curves in a 3D world and I need to know of those ways as I am tail chasing.

I did try for surface through points choosing either end and its middle but that surface didnt give me the right angle to set a Cplane to.

Anyway what if a curve starts off in one plane the twists to end up in another plane, no cplane would fit it.

Steve

You’re going to have to bite the bullet and create a custom CPlane to that “planar sheet” (if it’s not along one of the principal planes), then you can use Ortho, the Nudge keys (set to CPLane), and Gumball (set to CPLane) to move your points in a constrained manner along the CPlane axes.

–Mitch

Other ways to make 2D curves:

If a curve needs to lie in plane parallel to one of the construction planes or world planes then SetPt can be used to set all the world or local x, y or z coordinate values to the same value.

If the curve needs to lie in an arbitrary plane then if a surface can be created in the desired plane Pull can be used to pull the curve onto the surface and plane. I typically create a planer surface using SrfPt with 3 pts. Then I untrim the resulting surface and use ExtendSrf to extend as needed so that the surface will contain the plane.

For 3D curve creation, also check out Crv2View:
http://docs.mcneel.com/rhino/5/help/en-us/commands/crv2view.htm

Cheers Guys.

I established where the planar surface for the curve headed, they all radiated from aircraft engine thrust line, and set about making quite a few Cplanes based on surface through points ! plotting a few points along the curves and a couple on the thrust line. Then life was easy, I took the profiles and intersected them with the planar srf then was able to draw the other curves through these points. also I opted for extrude srf from crv, the line that I wanted to improve onto the surface, could have used project as well.

The fun though happens when a curve twists through space !

Any tutorials on all of this aspect of working on curves in a 3d world when they twist and are not planar or are on an arbitray plane would be most welcome.

Where are the tutorials ?

The link by the way sees a fault in the image.

Steve