RBD Fracture Transforms

[Jesper Rahlff]

Hey ODFORCE!

Quick question here.

I have a low res box which I fractured and added some velocity to
I have a plate for this, that is in slowmotion, so what I have done is simming it to a normal speed plate, and then I want to slow it down post sim.

So here is what I have planned for it, but I might need some help to execute this.

PLAN:

I take my cached simulation, and in a foreach node create a centroid on each piece, and then create and ID attribute on each point.

Then I use a timewarp and timeblend to slow the centroid points down to the appropriate speed for the plate. I have then timeshiftet my cache on a second branch to frame one, and what I want to do now is transfer the transform information from my centroid points back to my pieces, giving them the slowed down transformation.

This sounds simple in theory (maybe it really is), but I cannot seem to figure out how to do this?
 

if anybody have a quick solution for this I would appreciate it. Also if you know a better way of doing this please let me know.

 

I cannot unfortunately post my scene file due to this being a shot I am working on at work.

 

 

[dchow1992]

i might be misunderstanding you but is there something stopping you from putting a timeshift with something like $FF/4 and integer frames unchecked before you write to disk?

[Jordan Walsh]

When fracturing just use packed fragments. This will give you exactly what you are looking for, centroids, transform matrix pre piece etc. You may want to have a look at the Transform Pieces sop too if you need to re apply the transforms to different geo.

If you are using a timeblend and packed geo make sure you turn on "Shortest Path Transform Blending" to get correctly blended matrix transforms.

[Jesper Rahlff]

On 8/13/2016 at 9:51 PM, dchow1992 said:

i might be misunderstanding you but is there something stopping you from putting a timeshift with something like $FF/4 and integer frames unchecked before you write to disk?

You are absolutely right, that approach works. I did not think of that. This ended up being the method I used for the shot

14 hours ago, Jordan Walsh said:

When fracturing just use packed fragments. This will give you exactly what you are looking for, centroids, transform matrix pre piece etc. You may want to have a look at the Transform Pieces sop too if you need to re apply the transforms to different geo.

If you are using a timeblend and packed geo make sure you turn on "Shortest Path Transform Blending" to get correctly blended matrix transforms.

Nice approach. I was not familiar with the Transform pieces sop. That sop actually does what I tried to do manually in vops . I will definately have this approach in mind for something a bit more complex than what I am during now. For now DcHow1992 approach worked smoothly for what I needed.

 

Overall thanks for your feedback guys.