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View Full Version : Sliding vertices along splines?

astrofish
06-15-2003, 09:40 AM
I'd like to be able to:-

1. Select an edge loop of an object,
2. create a smooth spline from the selection,
3. slide the original vertices along this spline.

1&2 are no big problem (although I found I had to manually delete the last point in the spline (duplicate of the first) and then reselect 'close' again, otherwise the curve is messed up. Also I had to set intermediate pints to adaptive, to get the spline to display properly)

3 By turning on 3D snap to spline in the snap settings I can select any single vertex, and drag it along the spline. This is almost what I want, but I'd like to be able to select several (or al) ofl the original vertices and slide them all along the spline simultaneously...

Anyone know how to do this?

Cheers - Steve

[Edit: FYI, 1 and 2 were performed by:-
Selecting one or more edges in editor.
R-click -> Edge Loop
Structure -> Edge selection to spline.
Select the spline, switch to structure panel.
Check that the first and last points have identical coords, then delete the last point.
Switch to attribs panel.
Select Close Spline, Bezier, Adaptive.
]
tcastudios
06-15-2003, 06:21 PM
Hey that was good to try out! Perfect for a "Swallowing an apple".

An idea for your problem might be to have the vertices locked to objects that are "Following A Spline"

Cheers
Lennart
tcastudios
06-15-2003, 06:39 PM
Just tried it, and it worked.

Using the objects "object" > "object in" on a PointNode. And then the Null (that AlignsToSpline) position connected to "point position" on the PointNode.


Cheers
Lennart
tcastudios
06-15-2003, 07:57 PM
Sorry if I´m going over the top. It was just fun to try.

http://homepage.mac.com/tcastudios/Cinema/MV2.gif

http://homepage.mac.com/tcastudios/Cinema/MVhow.jpg
astrofish
06-15-2003, 10:36 PM
Hi,
Thanks for the suggestion - that's an approach I hadn't thought of. I've only just started playing with XPresso really, it seems to have a lot of potential...

However, whilst the technique you suggested seems fine for doing vertex animation, it's not quite what I was looking for. I got it working, but it takes a fair amount of setting up. I'm looking for a 'modelling' type solution that will allow me to effectively 'twist' a ring of vertices whilst preserving the basic shape - without having to set up a load of rigging (otherwise it's no faster than just moving the vertices one by one).

For example, suppose you've got a vertical cylinder, and you select a horizontal edge loop (circle). Using the rotate tool you can rotate those vertices in-plane around the circle, resulting in a twist in the cylinder, whilst preserving the circular profile.

This works fine for cylinders, but suppose the cross section is not circular. Rotating will now change the basic underlying shape.

So, what I want to do is to extract the spline profile, and rotate the vertices whilst keeping them confined to the spline. It seems that I can do that for a single vertex at a time using the original technique I described, but I'd like to be able to do it for all the vertices in one go because it's quicker, but also it will be easier to preserve the spacings.

Doing it one vertex at a time isn't too much of a hardship, but I was just wondering if there was some devious trick that would let me do it all in one.

Cheers - Steve
tcastudios
06-15-2003, 11:47 PM
I realize it was more of a modelling issue. I just got a little carried away there...

I have no other idea.

Cheers
Lennart
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