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Kaare Baekgaard

Failing nurbs control points snap - please help!

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I just updated from VW2008 to 2011.

While fooling around with new functions, I discover - oh horror! - that I can no longer make 2D lines snap to the control points of a nurbs surface. Hopefully it is just because I have not yet discovered how...

This function is absolutely crucial to my work with nurbs surfaces, so I hope it did not fall out of the program. Can anyone please help me?

I include an image to illustrate the problem:


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I have submitted this as a bug - although it might just have been an oversight. I sure hope, that the guys in NNA will fix it. For those, who does not see the problem, here is an image, that should explain it.

Other than that, I am very pleased with the new features in VW20011.


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A question for you (unfortunately not an answer to your problem above):

If I want to snap one NURBS to another in 3D, it seems possible only at certain points along the curve. This is not the case in other apps (Shark, for example).

Is this the same for you? This also seems like an oversight, but it seems important.


Also, I am not quite sure I understand your dilemma above; could you elaborate a little more. I know this kind of thing is sometimes hard to explain...

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I do seem to be able to snap degree-1 NURBS to control points now. Not at any point on a curve, but on the midpoint and control points. Does that work for you?

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Thanks for the input mmyoung.

If I turn on the 'Nearest Point on Edge' option in smartcursor settings, I can get the snap, you are looking for.

Well it does seem, that I fail to explain the issue. I just got the 'its not my job' brush off from Jim at tech support. If he represents policy at NNA regarding customers concerns it would read something like:

1. Ask an irrelevant question

2. Give an answer to a question, that was not asked

3. Refer the complaint to the local dealer

4. Ignore any follow-up mail

Being a customer since MiniCad 2, its quite frustrating to be handled like a newbie, who cannot find the ins and outs of the program. If there is a moderator here, please give Jim a shake from me.

Sorry for the rant.

The dillemma is, that there are only two ways to accurately position nurbs points in VW. One is to manually enter the position of each vertex in the object info palette (which is very slow work), the other is - or was in VW 2008 - to snap the vertexes to 'help objects' like the endpoints of lines. In order to create a help object, I need to snap it to one or two of the nurbs vertexes involved, which I can no longer do.

I use this in 3 separate workflows:

1. To mirror nurbspoints over an axis in a symmetric nurbs surface (can't always use two half surfaces)

2. To acurately control a smooth transition between adjoining surfaces (can't always use the connect/Combine tool with acuracy)

3. To make nurbs surface corner vertexes form part of a curve (can't always use trimmed surfaces)

So I need to snap to the vertex points of surfaces - not just the edges and corner points and not of nurbs curves, but of surfaces. I still have not found out, if anybody else can do this - or if it is just a problem with my installation.

Can anyone make a line snap to the point represented by a blue square dot in this setup:?


If so or if not, please let me know. It's kinda important

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Hi Kaare,

THANK YOU! for that setting (Nearest Point on Edge). Don't know how I missed it. I had some tedious workarounds.


? I cannot snap to the control points of a surface or NURB Spline.

The control points are visible to me only when I'm in 3D Reshape.

I can snap the control points to existing objects (help objects), but not the other way 'round (can't snap existing objects to them, because I can't see them).

v2008 is no longer loaded on my machine. Were the control points visible in 2008 when you weren't in 3D Reshape??

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I cannot snap a control point to a surface, either a planar extruded surface (the side of an extruded rectangle) or to a NURBS surface. I CAN snap NURBSpoints to edges, vertices, and to contours I generate, but that's it.

Is this what you needed?

re/ your "rant," it does seem to me the tech support folks at NV are not deeply familiar with 3D, especially NURBS yet. I don't see many users pushing the app like you do, so I'm not sure they get much call for it, though that will need to change now that more of us are working that way.

There ought to be an option to leave the controls visible, and snapping to a surface is actually the reason NURBS surfaces were invented, I believe. Will Rhino do that? I've not worked with an app that will do it yet.

Edited by mmyoung

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Thanks for the feedback mmyoung.

Can't get my head around Rhino, but it does provide the snaps.

Just got feedback from tech, that this issue will be fixed in SP2.

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