How to model/animate a bellow cover

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  11 November 2013
You can add a helper (an ExposeTM) to read the distance in real time (inside the reaction manager).
Or add the distance as a formula in the same place with this sentence:
HTML Code:
distance $Object01.pos $Object02.pos
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Fernando Ferro
www.reconstruccionvirtual.com
 
  11 November 2013
Perfect, thanks! I guess I have to read up on the reaction manager a bit
 
  11 November 2013
You may be able to set this up more easily without the reaction manager by simply using a linear spline segment that you path constrain all your objects to at different percentages (remove animation). Then scale the line itself with an XForm.

See this test:

LineContract.max

Also, if you path constrain your first object and then delete its animation, then you shift drag the object along the spline you can copy (or instance) multiples along the spline with the correct spacing and path constraint setup automagically.
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--Pel
 
  11 November 2013
It is amazing what you can do with splines. I try to use them whenever possible due to their flexibility (pun intended).

I think that your parts, with the spline technique in the above LineContract.max scene would work quite well. You could possibly bend it as well.
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--Pel
 
  11 November 2013
Originally Posted by PelDaddy: You may be able to set this up more easily without the reaction manager by simply using a linear spline segment that you path constrain all your objects to at different percentages (remove animation). Then scale the line itself with an XForm.

Also, if you path constrain your first object and then delete its animation, then you shift drag the object along the spline you can copy (or instance) multiples along the spline with the correct spacing and path constraint setup automagically.

I actually did ALL of that in my scene, but thanks anyway

Linking the spline to the dummies is just for convenience though (in the end I will have two of these bellows with a dolly inbetween them, and I only want to animate the dolly to make the two inner ends of the bellows follow it). And as I explained, I used the reaction manager to make the fabric parts fold and stretch correctly, so I still need the reaction manager.

Also I just got the idea that instead of using the distance between the dummies to determine the folding and chamfering, I should better use the length of the spline between them. That way I can set the two vertices of the spline to bezier and get some bending in the spline by rotating the dummies.

The only thing I still have to figure out is a bit of "wobble" I want to get along the squeezing axis when the dolly stops, so that the bellow appears more flexible. I guess it can be done with a soft selection and the Flex modifier on the bellow geometry, although it would be better to have the wobble already appear in the animation of the underlying rectangles.
 
  11 November 2013
Originally Posted by Laserschwert: I actually did ALL of that in my scene, but thanks anyway


Haha! I did not look closely enough... Yeah, the spline thing works great.

I don't have Quad Chamfer installed; so I could not see your Reaction working. I saw the settings though.

I need to get Quad Chamfer

Anyway, nice job.

For the flex I would see if there was a way to add some smooth points to the spline and put flex on those or something (which may be what you said you are doing, but I thought you were going to try it on the finished mesh).
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--Pel
 
  11 November 2013
So I made a quick test and putting the flex on the bellow geometry works good enough for this (since the wobble will only be very subtle). I've put a map based VolumeSelect on top of the SkinWrap, using a black-white-black gradient ramp so that only the middle part of the bellow wobbles, not the fixed ends. The UVW modifier for this map is put under the SkinWrap, so that it scales with the expanding and contracting geometry.

And now I have to do it all again for the second bellow

Edit: Ah well, it looks like I were able to copy the whole thing without problems. Even the reaction manager setup was copied correctly. Nice

Last edited by Laserschwert : 11 November 2013 at 12:28 PM.
 
  11 November 2013
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