houdini dop inherit velocity

[ahmedsheeraz]

Hi all

have a question. I am using voronoi fracture for chunks and inheriting velocity and active attributes in dopnet, active attribute is working fine but velocity is not working, i want the chunks on active to explode rather than simply go down. i tried sop solver in dops to bring in velocity manually using attribute wrangle and its working fine but the problem is it is continuous and pieces affected by velocity always but i want as long as active attribute is 1 on any piece it gets velocity to explode rather than continue with velocity. any help? i have attached hip file and image.

thanks in advance

chkbox.hip

[mestela]

Here's one way, there's no doubt many ways to achieve this effect.

As you say, if you set @v in sops and enable 'inherit from points' in rbd, it only works on the first frame. if you enable 'overwrite attributes from sops' and specify v, then it clashes with the rbd solver which is also trying to set @v, and your pieces fly away.

One way around this is to detect the first frame a piece is made active, and only add @v for that frame. Here I use a timeshift to move the geometry back by 1 frame, and I copy active from the shifted geo to the normal geo with a new attib name @active_prev.

In dops, I added a wrangle that just tests if @active != @active_prev. The only time they won't be different is on the first frame the piece is made active. As such, I add @v by pulling it directly from sops. The rest of the time, rbd will set @v by itself.

chkbox_fix.hipnc

[6ril]

Useful trick, thank you Matt !

 

[ahmedsheeraz]

On 5/5/2016 at 7:43 PM, mestela said:

Here's one way, there's no doubt many ways to achieve this effect.

As you say, if you set @v in sops and enable 'inherit from points' in rbd, it only works on the first frame. if you enable 'overwrite attributes from sops' and specify v, then it clashes with the rbd solver which is also trying to set @v, and your pieces fly away.

One way around this is to detect the first frame a piece is made active, and only add @v for that frame. Here I use a timeshift to move the geometry back by 1 frame, and I copy active from the shifted geo to the normal geo with a new attib name @active_prev.

In dops, I added a wrangle that just tests if @active != @active_prev. The only time they won't be different is on the first frame the piece is made active. As such, I add @v by pulling it directly from sops. The rest of the time, rbd will set @v by itself.

chkbox_fix.hipnc

Oh yes!! that's gr8 although i got late to watch this. i don't know why od forum didn't send me notification about this reply. thanks a lot

[pseudopod7]

Matt, you just saved my weekend!

thank you!!!!

[freko12]

On 5/5/2016 at 9:13 PM, mestela said:

Here's one way, there's no doubt many ways to achieve this effect.

As you say, if you set @v in sops and enable 'inherit from points' in rbd, it only works on the first frame. if you enable 'overwrite attributes from sops' and specify v, then it clashes with the rbd solver which is also trying to set @v, and your pieces fly away.

One way around this is to detect the first frame a piece is made active, and only add @v for that frame. Here I use a timeshift to move the geometry back by 1 frame, and I copy active from the shifted geo to the normal geo with a new attib name @active_prev.

In dops, I added a wrangle that just tests if @active != @active_prev. The only time they won't be different is on the first frame the piece is made active. As such, I add @v by pulling it directly from sops. The rest of the time, rbd will set @v by itself.

chkbox_fix.hipnc

This is amazing!! but any way to get this in the rbdbulletsolver sop?

Edited May 26, 2022 by freko12

[mestela]

Yeah, needs some adjusting, but it works.

rbd_animated_force.hip

[matEvil]

thanks, Matt for sharing your knowledge, but if I want to be moved up/down the pieces are on the edge like a line across it and open like a crack it, how can I do that?

 

I attached an Image for a better description

 

Thanks a lot

Matteo