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kiryha

Can`t modify constraint strength

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I made a setup based on this topic. In my DOP net, I create a sopsolver1 where I modify constraints as I need. It's working but when I try to reduce the strength of selected constraints (group DEL) it does not affect the simulation (while deleting primitives works, see commented line in sopsolver1/str wrangle). Attribute spreadsheet also shows the necessary value... What do I miss?

I need to overwrite the strength value (set in dopnet1/glueconrel1) for particular parts of constraints (selected in group DEL) to fix left hand.

reduceStrength_001.hipnc

BRK_01.gif.8f0784df88999579ac58ca10a54727f5.gif

Edited by kiryha

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Maybe I am doing something wrong but the scene does not work... Constraints do not break. 
 

Also, I have setup in place and its working for all tasks but this case and I keen to get this way to work, rather then recreate everything in a different way, if its possible.

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Does not work in 16.5 (which I am using) but works in 17...

But this setup breaks constraints, I need to modify strength... Anyway, thanks Hernan, I will try to get some thoughts to fix my setup.

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Gotcha, Well I'm confused about exactly what you want to achieve. Anyway good luck!

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If all constraints have strength 10 000. I want to select several of them (via group SOP) and reduce strength to 100.

Wired that such a simple thing does not work in previous Houdini version.

const_16.5.thumb.PNG.e52f7c65b39bdbf7c412f840790c0431.PNG

Edited by kiryha

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8 hours ago, kiryha said:

If all constraints have strength 10 000. I want to select several of them (via group SOP) and reduce strength to 100.

Wired that such a simple thing does not work in previous Houdini version.

Hi, I've looked your file from first post and it work as it should. It doesn't affect because or two things. First you set @strength in SOP to 100 000 but actually it 10 000 000. The parameter strength of glue constraint is behaving as multiplayer and it has value 100 now. For don't get confused it is good to set it to 1 if you are setting this attribute in SOP as in your case. And second main thing - for now impact don't propagate to constraints in group DEL, so you sould increase parameter Propagation Iteration in glue constraint DOP like 5 or bigger.

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Hi, Victor,

I reduce strength in SOP to 1 and rise Propagation Iteration and it still does not work... Since I try to multiply by zero I did not think it does matter what initial value to set cos it should be zero anyway.

Here is the scene file: reduceStrength_002.hipnc

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It does not work in Houdini 16.5 but works in 17. Or maybe works but opening the same file in 16.5 and 17 gives different results.

I ended up by creating another constraint for the part which required different behavior.

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Yes, glue constraint parameter Propagation Iteration appeared since H17.0 thus to get the same result in H16.5 you should set detail attribute i@propagate_iteration in SOP and i increase value of @strength some more in wrangle from 1000 000 to 1 500 000.

reduceStrength_002_fix_h16.5.hipnc

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Great, thanks, Victor! So @propagate_iteration was the trick.

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