grouping first/last points on sweep

[barad_dur]

Hello all,

I have a circle sweeping down a resampled curve. I need to be able to group the first set of points and the last set of points. I would like to run a mountain SOP on all the points BUT the first and last point sets so the ends of the tube will be unaffected by the mountain SOP. At least 3 variables will change at any given time:

• The divisions of the circle (../circle1/divs)
  
• The segments of the resample (../resample1/segs)
  
• The length and shape of the curve
  

I am hoping there is a way to use a Group SOP to do this and need some help. I tried the following in the "pattern":

0-`ch("../circle1/divs")-1`

This does work for the very first set of points and updates when I change the detail of circle1. However, doing the following seems to break the Group SOP:

0-`ch("../circle1/divs")-1` `ch(../circle1/divs) * ch(../resample1/segs)`-$N

I was hoping this would evaluate to:

0-19 1420-$N (when there are 20 divs on the circle and 71 segments in resample)

It is not doing so and I think it's because I am pushing the group SOP's Pattern to hard.

Does anyone have an idea how to get this done? Any help would be appreciated. Thank you

David

Edited August 14, 2013 by barad_dur

[CtrlLoki]

Instead of 'pattern' on the GroupSop you could instead use 'bounding' and place one over each end of your curve?

[magneto]

You can just group the first and last primitive using:

0 $N[/CODE]

and then convert it to a point group within the same Group node.

[barad_dur]

I tried it a bit but I forgot to mention that this curve will also be changing as I generate different tubes of varying radius, length and postions of the end points of the sweep curve.

[Adam T]

I tried it a bit but I forgot to mention that this curve will also be changing as I generate different tubes of varying radius, length and postions of the end points of the sweep curve.

Add Caps to your Sweep and $N `$N-1` in a primitive group pattern will get your caps primitives, from which you can get the points (fuse first), and then blast the caps, as attached. Not pretty, but it works. Example attached.

SweepEndpointsGrouping.hipnc

[Adam T]

Or, if you've not had too much coffee like me, you can avoid being complicated and just group Unshared Edges -> Convert to Points (although the above method is fair enough if you want to group the ends seperately I guess).

Edited August 14, 2013 by Adam T

[barad_dur]

Adam,

Thank you. This totally works. It's perfect.

David