Path constraint : flipping problem

[erilaz]

So the general gist is you're trying make a different form of max's spline-IK? I got a bit lost in the middle there.

[Nham]

you're trying make a different form of max's spline-IK?

In a way, yes.

Actually my problem could be reduced at a path constraint flipping problem. I have several objects path-constrained to the curve (without any animation, to make them stick at a particular path percentage).

These objects have to be skinned to the body to form vertebraes. But as exposed in my original post, I can't avoid the flipping problem when passing the world Z-axis.

Try it if you don't know this problem :D .

[PEN]

Well I do spine rigs like this all the time. You need to use lookat constraints and orientation contraints in there as well. The spline IK in Max isn't very good and I never use it. My second DVD covers how I deal with it in detail if you are interested.

[Gravey]

Firstly, for a total solution I recommend Paul's DVD.

Beyond that, I've been playing with your idea of directly controlling verts on a spline for several hours now - mainly getting it all to come together in maxscript. It was quite hard to figure out and I end up getting there in a less than desireable way but the code is still fairly short and the main part is it works! Here's what I've come up with:
if selection.count == 1 AND $.category == #Splines do
(
animateVertex $ #all --give all verts animation controllers
--access to the controllers is by newly created properties
--so we get all properties and filter for the ones we want
props = getPropNames $
pat = "Spline_1___Vertex_*"
for g in props do
(
temp = g as string
if (matchPattern g pattern:pat) do
(
--get the vertex number of the each vert
num = (replace temp 1 18 "") as integer
--create a point at each vert
p = point pos:(getKnotPoint $ 1 num)
--create a script controller for each vert
setPropertyController $ g (point3_script())
--add some variables and the new script
c = getPropertyController $ g
c.addTarget "pos" p.pos.controller
c.addNode "par" $
c.script = "pos * inverse par.transform"
)
)
)
Hopefully the commenting is descriptive enough for you. Any questions be sure to ask.

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