Cineversity

Hello

I’m having some issues with Spline Dynamics and collisions.  See the attached file, I have 4 cylinders that the spline is supposed to collide with, but I’m getting a lot of “pass through” effect, as if the spline ignored the cylinder after a while.  I doubled the steps and iterations on the spline dynamics tag, but no luck…

https://www.dropbox.com/s/5huhsgol4087org/CrissCrossTension_CollisionProblem.c4d?dl=0

How can I make the sure the spline does not pass through the cylinders?

Thanks!

Hi Alex,

Please have a look at the clip. I think it explains it very clearly. Just one minute. For Hair set ups I avoid suggesting this, as with thousands of hairs that collision becomes perhaps quite slow. But for a set up like this, I guess that will work.

Scree-capture:
https://www.amazon.com/clouddrive/share/7soqjvHsDaq8bg3oLofrAbbU411EGWPYDmqIhk3JeAq?ref_=cd_ph_share_link_copy

All the best

P.S:

This seems to be a good starting point, with 6 times the points. It changes the appearance. So, why not optimize it more? As I have no idea if that is an example file or the final. The small cylinder has problems with 24 times the points. So, it is a little bit of trial and error.

The file below has a Cache file in the folder, you can load it in the Spline Dynamics:
https://www.amazon.com/clouddrive/share/3s74exD92asfhiBW4OKzg6cFtmxsekjNRq4t1BGm3WY?ref_=cd_ph_share_link_copy

Chris Schmidt has a more complex/advanced idea how to create such flexible dynamics:
https://www.cineversity.com/vidplaytut/siggraph_2016_rewind_-_chris_schmidt_creating_advanced_controllable_dynamic

The idea of Soft Bodies for this is used in this file:
https://www.amazon.com/clouddrive/share/MXsCDGo5gJfwCSsjevtUQlhIqzHesqqan5VJeHyGjMp?ref_=cd_ph_share_link_copy
Note that I have cached it, if you change it un-cache it.

My best wishes for the project

Thanks Sassi!
I’ll look at the Chris Schmidt video.  For the file you sent, you are essentially just adding points?  That’s what I understood from your video, i.e that the vertices of the spline are the places where dynamics get calculated.

One question though…Do you have to disable spline dynamics and constraints every time you want to subdivide?  I haven’t found a way around that…Would be great to parametrically add points to the spline, check the behavior, reduce the point count to optimize and change the look etc…

Thanks!

Hi Alex,

There is a second option, to use Dynamics (instead of Spline Dynamics), the Soft Body option.

Yes, the subdivision will not work while anything is active, mostly based on the point number and its “anchors”.

The Soft Body might work as Chris mentions it with the point number 0 and -1, but the change of points will alter the entry “Set Initial State”, which is not simple in this file. I played a few frames from 0-5 for example, then set the Initial State. Went back to frame zero and played 0-5, set state, etc, etc. To get the least heavy change from frame zero. If drawn closely from the start to a plausible shape, it might work faster.

All the best