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Author Topic: Unexpected Compose operator results at both ends of a spline  (Read 431 times)

antmarch

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Unexpected Compose operator results at both ends of a spline
« on: December 13, 2016, 03:50:04 PM »
Could you explain why it is that a compose operator trio of segments is acting differently at the start and end of a spline than it does as an evenly (or corner?).



The posts are composed of three segments, 1-post,2-base and 3-cap.  I've chosen to do it as a compose operator, as the height is wired to an arithmetic that also controls the height of the top bar.

All segments have the pivot aligned and set to the X-& Y centre of the object.  The following screen grab shows the left hand piece is moved along the X to the right, and the right hand piece, is moved to the left by way of the preceding segment's right hand padding.



I thought the compose operator aligned to the centre or pivot of the middle segment (the base of the post).  You can see that on th end it is aligned, but on the start it is slightly off. Can't work out why the segments are behaving this way.  If I set the values back to zero, you'd expect the composed objects to all look the same, but they don't.    The clamps (cylinders aligned to the bars) are from a separate linear generator and this is what I hope to align the posts too.

My model is using the adaptive ordering method and I'm wondering if this is something to do with it.

Michal Karmazín

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Re: Unexpected Compose operator results at both ends of a spline
« Reply #1 on: December 13, 2016, 05:37:32 PM »
Hi,

To avoid similar kind of troubles with the Evenly input (as the placement of these are calculated in a slightly different way), using Transform - Translation (not Padding) for both Segments should fix it. Attaching a sample scene showing this set-up. Hope that'll help.

Best regadrs,
« Last Edit: December 13, 2016, 05:46:54 PM by Michal Karmazín »

antmarch

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Re: Unexpected Compose operator results at both ends of a spline
« Reply #2 on: December 13, 2016, 06:04:26 PM »
Unfortunately that approach doesn't make any difference.  The evenly are aligned, but both the ends are still the same as before.

I've found a work around, by just not using the posts at the end of the array, which isn't really ideal.  I'd have to create a separate compose for each end, with separate values to the others.
It doesn't help me move forward in understanding why it's doing it, or being able to utilise the compose operator more in the future.  IT seems like a handy op to combine geometry, but also brings it's own headache.  Surely with the pivots aligned, the compose objects should sit neatly.

Hard to understand.